SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

simjeb-bracket-fea-mass-prediction-real

claude-code claude-opus-4-8 ✗ failed GOOD_FAILURE ↑ View task
Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.
Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.
Classification , post-hoc; cannot change the reward
GOOD_FAILUREHonest miss, the agent ran correctly but couldn't solve it. Expected for a hard task; the task is sound.
SubtypeComplexity Overwhelm
EvidenceAgent achieved raw_score=0.41 (exactly at baseline), which produces reward=0.0 because score < 0.5 pass threshold. The task requires relative L2 error ≤ 0.204 to pass (50% improvement over baseline). Reference solution in solve.sh shows this is achievable with proper training. Agent's model checkpoint was created successfully with all required keys (feat_mean, feat_std, label_mean, label_std, state_dict), indicating the agent completed the training workflow but the trained model failed to generalize well to the hidden test set.
Root causeThe agent attempted a machine learning training task but the resulting model's predictions on the hidden test set achieved only baseline-level performance (rel_L2=0.41), indicating insufficient training convergence or optimization. This is a genuinely difficult task requiring proper understanding of deep learning, hyperparameter tuning, data augmentation, regularization, and normalization strategies.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
276 tool calls · 3 tool types · 276 steps
You are given point-cloud samples of 3D jet-engine bracket designs along with each bracket's FEA-derived mass (kg). Each point cloud is an unordered set of 2048 surface points in R^3; coordinates are pre-centered and rescaled so the axis-aligned bounding box of each bracket fits inside the unit cube. The mapping from geometry to mass is not given to you - you have to learn it from the data. Train a model that takes a `[2048, 3]` point cloud and predicts the scalar mass value. Your model is then applied to a held-out set of bracket geometries and the predictions are compared against the ground-truth FEA-simulated mass values. ## Files - `/app/data/{train,val,public_test}/samples.pt` - each file is a dict with keys `features` (shape `[N, 2048, 3]`) and `labels` (shape `[N, 1]`), both float16 on disk. Load with `torch.load(path, weights_only=True)`. - `/app/task_config.json` - architecture sizes and training defaults. - `/app/feature_schema.json` - input / label spec. - `/app/candidate_model.py` - the fixed PointNet-style architecture. Keep it as is; your saved checkpoint has to load back into this same architecture. - `/app/dataset.py` - a minimal loader for `samples.pt`. - `/app/train.py` - a small starter training loop you can extend or replace. ## What you must produce Write your trained checkpoint to `/app/outputs/model.pt` as a dict with the following required keys: - `state_dict` - your model's `state_dict()` mapping. - `feat_mean`, `feat_std` - length-3 tensors used to standardize the input coordinates before the forward pass. The same normalization is applied at inference time, so these are required. - `label_mean`, `label_std` - length-1 tensors used to standardize the target during training and de-standardize the model output at inference. The model's output is mapped back to physical units using these, so they are required too. The model must consume a `[B, 2048, 3]` tensor and produce a `[B, 1]` output. ## What you are optimizing Your predictions are measured against the true FEA-simulated mass labels with three error numbers, all lower is better: the relative L2 over the full set (the primary one), the mean absolute error, and the worst-case per-sample absolute error. A strong model needs to do well on all three, so do not trade one off against the others.
Let me start by exploring the environment to understand what I'm working with.
I'll start by exploring the environment to understand the task, the provided files, and the data.
bash
cd /app && ls -la && echo "---TASK CONFIG---" && cat task_config.json && echo "---FEATURE SCHEMA---" && cat feature_schema.json
output
total 14
drwxrws--- 3 h2tagent h2tagent  138 Jun 20 18:13 .
drwxr-xr-x 1 root     root     4096 Jun 20 20:59 ..
-rw-rw---- 1 h2tagent h2tagent 1639 Jun 20 18:10 candidate_model.py
drwxrws--- 5 h2tagent h2tagent   58 Jun 20 18:10 data
-rw-rw---- 1 h2tagent h2tagent 1183 Jun 20 18:10 dataset.py
-rw-rw---- 1 h2tagent h2tagent  499 Jun 20 18:10 feature_schema.json
-rw-rw---- 1 h2tagent h2tagent  581 Jun 20 18:10 task_config.json
-rw-rw---- 1 h2tagent h2tagent 3117 Jun 20 18:10 train.py
---TASK CONFIG---
{
  "task_id": "simjeb-bracket-fea-mass-prediction-real",
  "dataset_name": "simjeb-bracket-fea-mass-pilot",
  "n_points": 2048,
  "point_dim": 3,
  "label_dim": 1,
  "label_per_point": false,
  "seed": 20260518,
  "model": {
    "feature_width": 64,
    "global_width": 256,
    "head_width": 128
  },
  "training": {
    "epochs": 1,
    "batch_size": 16,
    "lr": 0.001,
    "weight_decay": 0.0001,
    "loss": "MSE"
  },
  "evaluation": {
    "primary_metric": "mass_rel_l2_score",
    "secondary_metrics": [
      "mass_mae_score",
      "mass_max_abs_err_score"
    ]
  }
}
---FEATURE SCHEMA---
{
  "version": "simjeb-bracket-fea-mass-pilot-v1",
  "input": {
    "type": "point_cloud",
    "n_points": 2048,
    "dim": 3,
    "coord_range": [
      -0.5,
      0.5
    ],
    "description": "Unordered surface point sample of a jet-engine bracket; each bracket mesh is centered at its bounding-box centroid and rescaled so the axis-aligned bounding box fits inside the unit cube."
  },
  "label": {
    "type": "scalar",
    "dim": 1,
    "description": "FEA-derived bracket mass in kg."
  }
}
Let me look at the model architecture, dataset loader, and training script.
Let me look at the provided model architecture, dataset loader, and training script.
bash
cd /app && echo "===== candidate_model.py =====" && cat candidate_model.py && echo "===== dataset.py =====" && cat dataset.py && echo "===== train.py =====" && cat train.py
output
===== candidate_model.py =====
from __future__ import annotations

from typing import Mapping

import torch
import torch.nn as nn


class SharedPointMLP(nn.Module):
    def __init__(self, in_dim: int, widths: tuple[int, ...]) -> None:
        super().__init__()
        layers: list[nn.Module] = []
        prev = in_dim
        for w in widths:
            layers.append(nn.Conv1d(prev, w, kernel_size=1))
            layers.append(nn.BatchNorm1d(w))
            layers.append(nn.GELU())
            prev = w
        self.net = nn.Sequential(*layers)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        return self.net(x)


class PointNetRegressor(nn.Module):
    def __init__(self, feature_width: int, global_width: int, head_width: int) -> None:
        super().__init__()
        self.feature = SharedPointMLP(3, (feature_width, feature_width, feature_width))
        self.lift = SharedPointMLP(feature_width, (feature_width * 2, global_width))
        self.head = nn.Sequential(
            nn.Linear(global_width, head_width),
            nn.GELU(),
            nn.Linear(head_width, head_width // 2),
            nn.GELU(),
            nn.Linear(head_width // 2, 1),
        )

    def forward(self, points: torch.Tensor) -> torch.Tensor:
        x = points.transpose(1, 2).contiguous()
        x = self.feature(x)
        x = self.lift(x)
        x = x.max(dim=2).values
        return self.head(x)


def build_model(config: Mapping) -> PointNetRegressor:
    m = config["model"]
    return PointNetRegressor(
        feature_width=int(m["feature_width"]),
        global_width=int(m["global_width"]),
        head_width=int(m["head_width"]),
    )
===== dataset.py =====
from __future__ import annotations

from pathlib import Path
from typing import Iterable

import torch
from torch.utils.data import Dataset


class SampleStore(Dataset):
    def __init__(self, split_dir: str | Path) -> None:
        self.dir = Path(split_dir)
        payload = torch.load(self.dir / "samples.pt", map_location="cpu", weights_only=True)
        self.features: torch.Tensor = payload["features"].float()
        self.labels: torch.Tensor = payload["labels"].float()
        if self.features.shape[0] != self.labels.shape[0]:
            raise ValueError("features and labels must have the same number of rows")

    def __len__(self) -> int:
        return self.features.shape[0]

    def __getitem__(self, idx: int) -> tuple[torch.Tensor, torch.Tensor]:
        return self.features[idx], self.labels[idx]


def iter_batches(
    x: torch.Tensor,
    y: torch.Tensor,
    batch_size: int,
    shuffle: bool = True,
) -> Iterable[tuple[torch.Tensor, torch.Tensor]]:
    n = x.shape[0]
    idx = torch.randperm(n) if shuffle else torch.arange(n)
    for start in range(0, n, batch_size):
        chunk = idx[start : start + batch_size]
        yield x[chunk], y[chunk]
===== train.py =====
from __future__ import annotations

import json
import os
import sys
from pathlib import Path

import torch
import torch.nn.functional as F

APP_DIR = Path(os.environ.get("APP_DIR", "/app"))
sys.path.insert(0, str(APP_DIR))

from candidate_model import build_model  # noqa: E402
from dataset import SampleStore, iter_batches  # noqa: E402


def _device() -> torch.device:
    if torch.cuda.is_available():
        return torch.device("cuda")
    if torch.backends.mps.is_available():
        return torch.device("mps")
    return torch.device("cpu")


def _load_config() -> dict:
    with (APP_DIR / "task_config.json").open() as fh:
        return json.load(fh)


def main() -> None:
    cfg = _load_config()
    device = _device()
    torch.manual_seed(int(cfg["seed"]))

    train = SampleStore(APP_DIR / "data" / "train")
    val = SampleStore(APP_DIR / "data" / "val")

    feat_mean = train.features.mean(dim=(0, 1), keepdim=True)
    feat_std = train.features.std(dim=(0, 1), keepdim=True).clamp_min(1e-6)
    label_mean = train.labels.mean(dim=(0,), keepdim=True)
    label_std = train.labels.st
…[truncated]
Now let me look at the data. Let me understand the shapes, sizes, and statistics.
Now let me inspect the data itself , shapes, sizes, and label statistics.
bash
cd /app && ls -la data && echo "---" && for split in train val public_test; do echo "=== $split ==="; ls -la data/$split; done
output
total 3
drwxrws--- 5 h2tagent h2tagent  58 Jun 20 18:10 .
drwxrws--- 3 h2tagent h2tagent 138 Jun 20 18:13 ..
drwxrws--- 2 h2tagent h2tagent  55 Jun 20 18:10 public_test
drwxrws--- 2 h2tagent h2tagent  55 Jun 20 18:10 train
drwxrws--- 2 h2tagent h2tagent  55 Jun 20 18:10 val
---
=== train ===
total 1210
drwxrws--- 2 h2tagent h2tagent      55 Jun 20 18:10 .
drwxrws--- 5 h2tagent h2tagent      58 Jun 20 18:10 ..
-rw-rw---- 1 h2tagent h2tagent    6483 Jun 20 18:10 manifest.jsonl
-rw-rw---- 1 h2tagent h2tagent 1230821 Jun 20 18:10 samples.pt
=== val ===
total 389
drwxrws--- 2 h2tagent h2tagent     55 Jun 20 18:10 .
drwxrws--- 5 h2tagent h2tagent     58 Jun 20 18:10 ..
-rw-rw---- 1 h2tagent h2tagent   2011 Jun 20 18:10 manifest.jsonl
-rw-rw---- 1 h2tagent h2tagent 395109 Jun 20 18:10 samples.pt
=== public_test ===
total 197
drwxrws--- 2 h2tagent h2tagent     55 Jun 20 18:10 .
drwxrws--- 5 h2tagent h2tagent     58 Jun 20 18:10 ..
-rw-rw---- 1 h2tagent h2tagent   1134 Jun 20 18:10 manifest.jsonl
-rw-rw---- 1 h2tagent h2tagent 198437 Jun 20 18:10 samples.pt
bash
cd /app && python3 -c "
import torch
for split in ['train','val','public_test']:
    d = torch.load(f'data/{split}/samples.pt', weights_only=True)
    f = d['features']; l = d['labels']
    print(f'=== {split} ===')
    print(' features', tuple(f.shape), f.dtype, ' labels', tuple(l.shape), l.dtype)
    ff = f.float(); ll = l.float()
    print(' label min/max/mean/std: %.4f %.4f %.4f %.4f' % (ll.min(), ll.max(), ll.mean(), ll.std()))
    print(' coord min/max: %.4f %.4f' % (ff.min(), ff.max()))
    print(' coord per-axis mean:', ff.mean(dim=(0,1)).tolist())
    print(' coord per-axis std :', ff.std(dim=(0,1)).tolist())
"
output
=== train ===
 features (100, 2048, 3) torch.float16  labels (100, 1) torch.float16
 label min/max/mean/std: 0.2078 2.2188 0.7476 0.3895
 coord min/max: -0.5000 0.5000
 coord per-axis mean: [-0.013504491187632084, 0.007462748326361179, -0.0709712877869606]
 coord per-axis std : [0.14211857318878174, 0.2701786458492279, 0.0871192067861557]
=== val ===
 features (32, 2048, 3) torch.float16  labels (32, 1) torch.float16
 label min/max/mean/std: 0.2937 2.0723 0.7622 0.4126
 coord min/max: -0.5000 0.5000
 coord per-axis mean: [-0.005372888408601284, 0.005196526646614075, -0.07424016296863556]
 coord per-axis std : [0.1418035924434662, 0.2656756639480591, 0.08837021142244339]
=== public_test ===
 features (16, 2048, 3) torch.float16  labels (16, 1) torch.float16
 label min/max/mean/std: 0.1984 1.4492 0.7296 0.3278
 coord min/max: -0.5000 0.5000
 coord per-axis mean: [-0.013821225613355637, 0.011655600741505623, -0.07381976395845413]
 coord per-axis std : [0.14321814477443695, 0.27090150117874146, 0.08569176495075226]
So we have a small dataset: - train: 100 samples - val: 32 samples - public_test: 16 samples Each is a point cloud of [2048, 3] and a scalar mass label. The labels range roughly from 0.2 to 2.2 kg. This is a small-data regression problem. Only 100 training samples. The challenge is overfitting. Let me look at the manifests. Let me check the manifest files for more context.
The dataset is small: 100 train, 32 val, 16 public_test. Let me check the manifests for additional context.
bash
cd /app && echo "=== train manifest (first 3) ===" && head -n 3 data/train/manifest.jsonl && echo "=== val manifest (first 2) ===" && head -n 2 data/val/manifest.jsonl && echo "=== public_test manifest (first 2) ===" && head -n 2 data/public_test/manifest.jsonl && echo "=== counts ===" && for s in train val public_test; do echo -n "$s: "; wc -l < data/$s/manifest.jsonl; done
output
=== train manifest (first 3) ===
{"id": "train_0000", "source_bracket_id": 214, "n_points": 2048}
{"id": "train_0001", "source_bracket_id": 538, "n_points": 2048}
{"id": "train_0002", "source_bracket_id": 546, "n_points": 2048}
=== val manifest (first 2) ===
{"id": "val_0000", "source_bracket_id": 418, "n_points": 2048}
{"id": "val_0001", "source_bracket_id": 441, "n_points": 2048}
=== public_test manifest (first 2) ===
{"id": "public_test_0000", "source_bracket_id": 461, "n_points": 2048}
{"id": "public_test_0001", "source_bracket_id": 440, "n_points": 2048}
=== counts ===
train: 100
val: 32
public_test: 16
bash
cd /app && python3 -c "
import json
ids = {}
for split in ['train','val','public_test']:
    s = set()
    with open(f'data/{split}/manifest.jsonl') as fh:
        for line in fh:
            s.add(json.loads(line)['source_bracket_id'])
    ids[split] = s
    print(split, 'unique brackets:', len(s))
print('train&val overlap:', len(ids['train']&ids['val']))
print('train&test overlap:', len(ids['train']&ids['public_test']))
print('val&test overlap:', len(ids['val']&ids['public_test']))
print('all source ids range:', min(min(v) for v in ids.values()), max(max(v) for v in ids.values()))
"
output
train unique brackets: 100
val unique brackets: 32
public_test unique brackets: 16
train&val overlap: 0
train&test overlap: 0
val&test overlap: 0
all source ids range: 0 634
So there's no overlap between train, val, and test. Each bracket is unique. This is the SimJEB dataset (Simulated Jet Engine Bracket), which has 381 brackets originally but here source ids range up to 634, so there may be augmented/generated variants. Key facts: - 100 train, 32 val, 16 test. Small data. - Goal: predict mass. Mass is physically related to volume of the bracket. Since point clouds are surface samples, mass correlates with the volume enclosed. But also the coordinates are rescaled so bounding box fits in unit cube , wait, this is important. "coordinates are pre-centered and rescaled so the axis-aligned bounding box of each bracket fits inside the unit cube." Wait , if each bracket is independently rescaled to fit in the unit cube, then scale information is lost! The mass would depend on the original physical size. But if each is rescaled independently, how can we recover absolute mass? Let me re-read: "coordinates are pre-centered and rescaled so the axis-aligned bounding box of each bracket fits inside the unit cube." Hmm, let me check the per-sample bounding boxes. If each is rescaled so that its bounding box fits inside the unit cube, the scaling might be uniform (same factor for all axes) preserving aspect ratio, or per-axis. Let me examine the per-sample bounding box extents. Actually, the key question: is the rescaling per-sample (each bracket scaled independently) or global (same scale for all)? If per-sample, then two geometrically similar brackets of different physical sizes would look identical after rescaling, making mass prediction impossible from shape alone , unless the scale factor is somehow encoded or the dataset doesn't have such degeneracy. Let me check per-sample bounding box sizes.
No overlap between splits , each bracket is unique. This is the SimJEB (Simulated Jet Engine Bracket) dataset. A crucial question: the prompt says each bracket is rescaled so its bounding box fits in the unit cube. I need to check whether that rescale is **per-sample** (which would destroy absolute-scale information needed for mass) or global, and how much bounding-box info survives.
bash
cd /app && python3 -c "
import torch
for split in ['train','val','public_test']:
    d = torch.load(f'data/{split}/samples.pt', weights_only=True)
    f = d['features'].float()
    # per-sample bounding box extents
    mn = f.min(dim=1).values  # [N,3]
    mx = f.max(dim=1).values
    ext = mx - mn             # [N,3]
    maxext = ext.max(dim=1).values  # largest axis extent per sample
    print(f'=== {split} ===')
    print(' per-axis extent mean:', ext.mean(dim=0).tolist())
    print(' max-axis extent: min=%.4f max=%.4f mean=%.4f' % (maxext.min(), maxext.max(), maxext.mean()))
    print(' centroid mean:', f.mean(dim=1).mean(dim=0).tolist())
"
output
=== train ===
 per-axis extent mean: [0.5887036323547363, 0.9991015791893005, 0.34989869594573975]
 max-axis extent: min=0.9912 max=1.0000 mean=0.9991
 centroid mean: [-0.013504491187632084, 0.007462748326361179, -0.0709712877869606]
=== val ===
 per-axis extent mean: [0.59246826171875, 0.9992523193359375, 0.35378265380859375]
 max-axis extent: min=0.9963 max=1.0000 mean=0.9993
 centroid mean: [-0.005372888874262571, 0.005196526180952787, -0.07424016296863556]
=== public_test ===
 per-axis extent mean: [0.5922698974609375, 0.9989013671875, 0.3443603515625]
 max-axis extent: min=0.9956 max=1.0000 mean=0.9989
 centroid mean: [-0.013821225613355637, 0.011655600741505623, -0.07381977140903473]
The max-axis extent is ~1.0 for all samples (the largest axis always spans the full unit cube). This confirms the rescaling is **per-sample and uniform** (isotropic): each bracket is scaled by a single factor so that its longest axis = 1.0. This means absolute scale information is lost , we only have the shape and aspect ratio. So mass must be predicted from shape alone (aspect ratios, relative proportions, how "chunky" vs "thin" the bracket is). The mass label presumably correlates with the actual material volume, but since scale is normalized away, the model learns the relationship between normalized shape and mass. Wait , but is that even a well-posed problem? If the original bracket were scaled up 2x, its mass would be 8x but its normalized point cloud identical. So there must be something that breaks this degeneracy. Possibilities: 1. The original brackets all fit in the same physical design envelope (the SimJEB brackets all share the same mounting interface / bounding constraints), so the physical scale is roughly constant across brackets. In that case, the normalization factor is roughly constant and the shape carries the mass info. 2. But the normalization removes the actual scale. Actually, in SimJEB, all brackets share the same 4 bolt holes and loading interface, fit within a common design space. Their actual physical dimensions vary though. Hmm. Regardless, the task is well-defined as a learning problem: learn f(normalized point cloud) -> mass. The correlation exists in the data. Our job is to fit it as well as possible and generalize. Let me not overthink the physics and focus on getting the best generalization. Actually, let me reconsider. The mass correlates with volume. For a surface point cloud normalized to unit cube, the "fraction of the cube filled" is the key. A bracket that's chunky/solid has more mass; a thin/hollow one less. The point cloud surface sampling density and distribution encode the shape. Let me think about what features predict mass well: - The extents (aspect ratio) , since normalized to max extent 1, the other two axes' extents tell aspect ratio. - The spatial distribution / how spread out vs concentrated. - Surface area proxies. Important: Since scale is normalized away, a pure PointNet on normalized coords can still learn shape->mass. But we lost absolute scale. The labels still have absolute values (0.2 to 2.2 kg). So the network must infer from shape proportions. Given the SimJEB brackets share design envelope, this works. Given only 100 training points, this is a very small-data regime. The fixed architecture is a PointNet regressor. Let me think about the best strategy: 1. Heavy data augmentation: random point resampling/dropout, jitter, small rotations (but rotations might change the bounding box normalization... careful). Actually the brackets have a fixed orientation (they're all aligned , y axis is the long one). Rotations would break the learned orientation-specific features. But small rotations + rescale could help generalization. However, since all brackets share orientation, augmenting with large rotations may hurt. Let me consider light augmentation: jitter, point resampling (subsample from 2048 with replacement), and maybe small scaling/rotation. Actually, a key and very effective augmentation for point clouds: random subsampling of points (dropout) and jitter. Also, since the mass is invariant to point ordering and to which 2048 points are sampled, resampling is natural. 2. The architecture uses BatchNorm1d. With batch size 16 and 100 samples, BN should be okay. 3. Normalization: The starter uses global feat_mean/feat_std over all points/samples. That's fine. But I must keep feat_mean/feat_std as length-3 and label_mean/label_std length-1. Let me think carefully about the loss. The primary metric is relative L2 over the full set: rel_l2 = ||pred - true||_2 / ||true||_2 = sqrt(sum (pred-true)^2) / sqrt(sum true^2). This is like a normalized RMSE. MAE and max …[truncated]
The max-axis extent is ~1.0 for every sample, confirming the normalization is **per-sample isotropic** (each bracket scaled so its longest axis spans the unit cube). Absolute scale is therefore removed, so mass must be inferred from shape/proportions. Since all SimJEB brackets share a common design envelope, this is learnable. Before building the model, let me run an exploratory analysis: how well do simple hand-crafted geometric features predict mass? This sets a baseline and sanity-checks learnability.
bash
cd /app && python3 -c "
import torch, numpy as np
def feats(f):
    # f: [N,2048,3]
    out=[]
    mn=f.min(1).values; mx=f.max(1).values; ext=mx-mn
    std=f.std(1)
    # pairwise-distance proxy via std magnitude; PCA eigenvalues
    N=f.shape[0]
    feat=[]
    for i in range(N):
        p=f[i]
        c=p-p.mean(0,keepdim=True)
        cov=(c.T@c)/p.shape[0]
        ev=torch.linalg.eigvalsh(cov)  # ascending
        feat.append(torch.cat([ext[i],std[i],ev]))
    return torch.stack(feat)
import numpy as np
tr=torch.load('data/train/samples.pt',weights_only=True)
va=torch.load('data/val/samples.pt',weights_only=True)
Xtr=feats(tr['features'].float()).numpy(); ytr=tr['labels'].float().numpy().ravel()
Xva=feats(va['features'].float()).numpy(); yva=va['labels'].float().numpy().ravel()
# standardize
mu=Xtr.mean(0); sd=Xtr.std(0)+1e-8
Xtr=(Xtr-mu)/sd; Xva=(Xva-mu)/sd
# linear regression closed form with ridge
import numpy as np
def ridge(X,y,lam):
    Xb=np.concatenate([X,np.ones((X.shape[0],1))],1)
    A=Xb.T@Xb+lam*np.eye(Xb.shape[1]); b=Xb.T@y
    w=np.linalg.solve(A,b); return w
def pred(X,w):
    Xb=np.concatenate([X,np.ones((X.shape[0],1))],1); return Xb@w
for lam in [0.1,1.0,10.0]:
    w=ridge(Xtr,ytr,lam)
    pv=pred(Xva,w)
    rl2=np.linalg.norm(pv-yva)/np.linalg.norm(yva)
    mae=np.mean(np.abs(pv-yva)); mx=np.max(np.abs(pv-yva))
    print(f'lam={lam}: val relL2={rl2:.4f} mae={mae:.4f} maxabs={mx:.4f}')
print('feature names: extX,extY,extZ, stdX,stdY,stdZ, ev0,ev1,ev2')
"
output
lam=0.1: val relL2=0.2877 mae=0.2074 maxabs=0.5371
lam=1.0: val relL2=0.2922 mae=0.2087 maxabs=0.5881
lam=10.0: val relL2=0.3101 mae=0.2101 maxabs=0.6806
feature names: extX,extY,extZ, stdX,stdY,stdZ, ev0,ev1,ev2
So simple 9-dim geometric features give val relL2 ~0.29. That's a baseline. A good PointNet should beat this significantly by capturing finer shape detail (how solid/chunky the bracket is). Let me think about what drives mass. Mass = density * volume. Volume of the solid bracket. From a surface point cloud (normalized to unit box), the volume fraction is key. Surface points sampled uniformly over the surface. The distribution of points encodes surface area and shape. Key insight: for a given normalized shape, mass relates to how much material. A voxel-occupancy estimate could be a strong feature. Let me test a voxel-based feature: voxelize the surface points into a grid and use occupancy counts, or estimate volume via some method. Actually, let me think about a powerful hand-crafted feature: voxelized occupancy. Divide unit cube into e.g. 16^3 voxels, mark voxels containing points. The number of occupied surface voxels ~ surface area. But volume (solid) is harder from surface points. However, for "filled" estimate we could try to fill interior. That's complex. Let me instead test richer features: a histogram of point coordinates (marginal distributions per axis), and voxel occupancy fraction at various resolutions, and see how predictive they are. If I can get a much better linear/MLP fit with voxel features, that tells me the PointNet should be able to learn it too. Actually, the PointNet architecture with max-pooling is somewhat limited at capturing density/volume (max pool loses counts). PointNet is good at detecting presence of features but max-pooling over points discards density information. For mass (volume), a sum/mean pooling or occupancy grid would be more natural. But I'm constrained to the fixed architecture which uses max pooling. Hmm. Wait, let me re-read the constraint. "candidate_model.py - the fixed PointNet-style architecture. Keep it as is; your saved checkpoint has to load back into this same architecture." So the architecture is fixed. The forward uses max pooling. I must work within this. But here's a clever trick: I can still preprocess the input coordinates any way I want BEFORE feeding to the model? No , at inference, the grader applies: normalize with feat_mean/feat_std, then forward. Let me think about exactly how inference works. The grader loads model.pt, builds the architecture, loads state_dict, then for each point cloud applies (x - feat_mean)/feat_std and runs forward, then de-standardizes output with label_mean/label_std. I don't control the inference code. So I cannot inject custom preprocessing beyond the linear normalization by feat_mean/feat_std (which is per-axis affine). So the input is essentially the raw normalized coordinates. So I must train the given PointNet (with max-pool) to map coords -> mass. Max pooling limits density info, but the network can still infer shape extent and proportions, and the head can learn correlation. Given the baseline linear on 9 features already gets 0.29, and PointNet can extract the extents and more, it should do better. Let me see how well a PointNet can do. Actually, max-pooling PointNet CAN encode a lot: each of the 256 global features is the max over points of some learned function of coordinates. This captures the spatial extent of various learned directions/regions , effectively the "support" of the shape in many projected directions, which encodes the convex-hull-like shape and aspect ratios well. Mass correlates with overall size/proportions, so this should work reasonably. But density/solidity (two shapes with same silhouette but different thickness) is hard for max-pool PointNet. However, since these are surface samples of solid brackets, the silhouette/extent in many directions likely correlates strongly with volume. Let me just build a strong training pipeline and measure. Let me first establish what the provided train.py gives as a baseline (1 epoch). Then improve. Let me check compute resources.
Simple 9-D geometric features already reach val relL2 ≈ 0.29. A PointNet should beat that. Let me check available compute, then establish the baseline from the provided starter.
bash
cd /app && python3 -c "
import torch, platform, os
print('torch', torch.__version__)
print('cuda available:', torch.cuda.is_available())
if torch.cuda.is_available():
    print('device:', torch.cuda.get_device_name(0))
print('cpu count:', os.cpu_count())
" && free -h 2>/dev/null | head -2
output
torch 2.5.1+cu124
cuda available: True
device: NVIDIA H100 80GB HBM3
cpu count: 3
               total        used        free      shared  buff/cache   available
Mem:            30Gi        64Mi        29Gi          0B        29Mi        29Gi
We have an H100 GPU. Great, training will be fast. The dataset is tiny (100 samples), so each epoch is trivial. I can train many epochs and ensembles. Let me establish a baseline metric computation function (rel L2, MAE, max abs), and a reusable training script. Let me write a helper eval function and run the starter train.py to see baseline. Let me first create an outputs dir and a metrics helper. Let me define the three metrics precisely: - mass_rel_l2: ||pred-true|| / ||true|| (L2 norms over the set) - mass_mae: mean |pred-true| - mass_max_abs_err: max |pred-true| These are "scores" in the config named mass_rel_l2_score etc. Lower is better per the prompt. Let me just compute the raw error metrics. Let me run the baseline starter training first.
We have an H100 and a tiny dataset, so I can train quickly and experiment freely. Let me run the provided starter to get a baseline, using a proper metrics helper.
bash
cd /app && mkdir -p outputs && python3 train.py 2>&1 | tail -5
output
[train] device=cuda epochs=1 samples=100 bs=16
[train] epoch=1/1 train_loss=1.20235 val_loss=1.08765
[train] wrote /app/outputs/model.pt
bash
cd /app && cat > /app/eval_ckpt.py << 'EOF'
import torch, sys, json
from pathlib import Path
sys.path.insert(0,'/app')
from candidate_model import build_model

def load_cfg():
    with open('/app/task_config.json') as fh: return json.load(fh)

def metrics(pred, true):
    pred=pred.ravel(); true=true.ravel()
    rel_l2 = (torch.linalg.norm(pred-true)/torch.linalg.norm(true)).item()
    mae = (pred-true).abs().mean().item()
    mx = (pred-true).abs().max().item()
    return rel_l2, mae, mx

def evaluate(ckpt_path='/app/outputs/model.pt', splits=('val','public_test')):
    cfg=load_cfg()
    ck=torch.load(ckpt_path, weights_only=True)
    model=build_model(cfg); model.load_state_dict(ck['state_dict']); model.eval().cuda()
    fm=ck['feat_mean'].view(1,1,3).cuda(); fs=ck['feat_std'].view(1,1,3).cuda()
    lm=ck['label_mean'].view(1,1).cuda(); ls=ck['label_std'].view(1,1).cuda()
    res={}
    for sp in splits:
        d=torch.load(f'/app/data/{sp}/samples.pt',weights_only=True)
        x=d['features'].float().cuda(); y=d['labels'].float().cuda()
        with torch.no_grad():
            xb=(x-fm)/fs
            out=[]
            for i in range(0,x.shape[0],64):
                out.append(model(xb[i:i+64]))
            p=torch.cat(out)*ls+lm
        res[sp]=metrics(p,y)
        print(f'  {sp:12s} relL2={res[sp][0]:.4f} mae={res[sp][1]:.4f} maxabs={res[sp][2]:.4f}')
    return res

if __name__=='__main__':
    ck = sys.argv[1] if len(sys.argv)>1 else '/app/outputs/model.pt'
    print(f'== {ck} ==')
    evaluate(ck)
EOF
python3 /app/eval_ckpt.py
output
== /app/outputs/model.pt ==
  val          relL2=0.4703 mae=0.3066 maxabs=1.3092
  public_test  relL2=0.4011 mae=0.2626 maxabs=0.6861
Baseline (1 epoch) gives val relL2 0.47, test 0.40. Worse than the linear feature baseline (0.29). Obviously 1 epoch is far too few. Let me now build a proper training pipeline with more epochs, augmentation, LR scheduling, and model selection. Let me design the full training approach: 1. Data loading: load train and val. Keep features in float32 on GPU. 2. Normalization: - feat_mean/feat_std: global per-axis. Actually, since each sample is already normalized to unit cube and roughly centered, I could use per-axis mean/std from train. The starter does this. Good. - label_mean/label_std: from train labels. 3. Augmentation (applied per batch on the fly): - Point resampling: randomly sample 2048 points with replacement from the 2048 (bootstrap) , mild. Or subsample a random subset and pad. Actually the cloud always has 2048 points. Resampling with replacement changes density slightly. - Random point dropout: randomly drop some points (set to a duplicate). Helps robustness. - Jitter: add small Gaussian noise to coordinates. - Random scaling: scale all coords by a factor near 1 (e.g., 0.9-1.1). But careful: scaling changes the bounding box. Since mass is about shape, uniform scaling of the normalized cloud would change apparent size but the label stays same. This could teach scale-invariance which may be GOOD because it prevents the model from relying on absolute normalized scale (which is already fixed at max-extent=1). Hmm, but actually uniform scaling would move points outside unit cube and change the max extent. Since the true data always has max extent=1, adding scale aug might hurt. Let me use very mild anisotropic scaling maybe. Actually, let me be careful and test augmentations empirically. - Random rotation: The brackets share a canonical orientation (y is long axis). Random SO(3) rotation would destroy this and likely hurt since test data is in canonical orientation too. Small rotations (few degrees) could help robustness. Let me test. Actually, I suspect small jitter + resampling/dropout are the safmost helpful. Let me test systematically. - Random flips/mirror: brackets may have symmetry. Mirroring along x (left-right) might be a valid symmetry for jet engine brackets if they're symmetric. Let me check if mirroring along some axis preserves shape distribution... risky. Let me test mirror along x and z. 4. Loss: MSE on standardized labels (primary rel L2). Maybe Huber. Test. 5. Optimizer: AdamW, cosine schedule with warmup. Weight decay for regularization (small data). 6. Regularization: dropout in head? The architecture is fixed , I can't add dropout layers (they're not in the architecture; adding would change state_dict keys, but loading would then fail? Actually state_dict would have extra/missing keys). I must keep architecture exactly. So no arch changes. Use weight decay, augmentation, early stopping, and SWA for regularization. 7. Model selection: use val relL2 for early stopping / best checkpoint. 8. SWA / weight averaging: average weights over last portion of training or over epochs with good val. Recompute BN stats. 9. Ensemble via weight averaging across multiple runs? Not valid across different inits. But SWA within a run is valid. Let me also reconsider: with only 100 training samples, a big risk is overfitting. The PointNet here has how many params? Let me count. Let me count parameters.
Baseline (1 epoch) is poor (val relL2 0.47). Let me count model parameters and then build a proper pipeline with more epochs, augmentation, scheduling, and validation-based selection.
bash
cd /app && python3 -c "
import json, torch
from candidate_model import build_model
cfg=json.load(open('task_config.json'))
m=build_model(cfg)
n=sum(p.numel() for p in m.parameters())
print('total params:', n)
for name,p in m.named_parameters():
    print(f'  {name:30s} {tuple(p.shape)}')
" | head -40
output
total params: 92289
  feature.net.0.weight           (64, 3, 1)
  feature.net.0.bias             (64,)
  feature.net.1.weight           (64,)
  feature.net.1.bias             (64,)
  feature.net.3.weight           (64, 64, 1)
  feature.net.3.bias             (64,)
  feature.net.4.weight           (64,)
  feature.net.4.bias             (64,)
  feature.net.6.weight           (64, 64, 1)
  feature.net.6.bias             (64,)
  feature.net.7.weight           (64,)
  feature.net.7.bias             (64,)
  lift.net.0.weight              (128, 64, 1)
  lift.net.0.bias                (128,)
  lift.net.1.weight              (128,)
  lift.net.1.bias                (128,)
  lift.net.3.weight              (256, 128, 1)
  lift.net.3.bias                (256,)
  lift.net.4.weight              (256,)
  lift.net.4.bias                (256,)
  head.0.weight                  (128, 256)
  head.0.bias                    (128,)
  head.2.weight                  (64, 128)
  head.2.bias                    (64,)
  head.4.weight                  (1, 64)
  head.4.bias                    (1,)
92k params, 100 training samples. Overfitting is a real risk but PointNet's weight sharing across points means the effective capacity relative to the 2048*100 point observations is okay. Still, I'll regularize. Let me build a comprehensive, configurable training script that I can experiment with. I'll make it support: - augmentation options (jitter, scale, rotation, dropout, mirror, resample) - loss options - epochs, lr, wd, scheduler - SWA - model selection on val - ensembling by weight averaging (SWA) Let me write a flexible trainer and run experiments. I'll keep data on GPU for speed. First, let me write a module with augmentation and training functions that I can import and call with different configs. I'll do a held-out evaluation on both val and public_test, but select based on val (to avoid overfitting to test). Actually, since the final grading is on a separate held-out set, I want the model that generalizes best. val (32) is my main proxy; public_test (16) is a secondary proxy. I'll look at both but be careful not to overfit to either. Let me think about cross-validation to get a more robust estimate. With 100 train samples, I could do k-fold CV to select hyperparameters more reliably, then train final model on all data. Given val is only 32 samples, CV on the combined 132 (train+val) would give more robust estimates. Let me implement a CV utility. Plan: 1. Write flexible train function. 2. Run a quick experiment: reasonable config (e.g., 200 epochs, AdamW, cosine, jitter+resample+dropout aug, MSE loss) and see val/test. 3. Tune augmentation and loss via CV. 4. Decide on SWA. 5. Train final model (possibly on train+val) and save. Let me write the training module. Actually, for robustness and to make best use of data, let me think about the final model data. The grader evaluates on a held-out set. My val and public_test are NOT the final set. So I'm free to train on train+val+public_test all combined for the final model (all 148 samples), since none of them is the final grading set. But I need some held-out signal to pick hyperparameters and decide when to stop. Approach: - Phase 1 (hyperparameter search): Use k-fold CV over train (or train+val) to select architecture-compatible hyperparameters (aug, loss, epochs, lr, wd, SWA settings). - Phase 2 (final training): Train on ALL available labeled data (train+val+public_test = 148 samples) with selected hyperparameters, using a fixed epoch count (no early stopping, since no held-out) OR use SWA which is less sensitive to exact stopping. Save that. But training without any validation risks picking a bad epoch. SWA mitigates this. Also, I can hold out a small internal validation from the combined set just to monitor, but use most data. Actually, a cleaner and very robust approach for small data: train an ensemble via cross-validation and average WEIGHTS? No, can't average across inits. Alternative: Since I must produce ONE model, I'll: 1. Use 5-fold CV to estimate generalization of a config. 2. Pick best config. 3. For the final model: train on all 148 samples for a fixed number of epochs (determined from CV, using the epoch that gave best average val), then apply SWA over the final epochs, recompute BN. Save. Let me be data-driven. Let me write the code. One concern: BatchNorm with the full-batch val forward. When doing model.eval(), BN uses running stats. During training the running stats get updated. For small data, BN running stats might be noisy. I should make sure to train enough for BN stats to stabilize, or use a larger batch. With 100 samples and bs=16, that's ~6 batches/epoch. Over many epochs running stats converge. For SWA I'll recompute BN stats by running a forward pass over training data in train mode with momentum=None (cumulative). Let me write the flexible trainer now.
The model has 92k params vs 100 training samples, so regularization and augmentation matter. Let me build a flexible, reusable training module so I can run controlled experiments and cross-validation.
bash
cd /app && cat > /app/trainer.py << 'EOF'
from __future__ import annotations
import json, math, copy
import torch, torch.nn as nn, torch.nn.functional as F
from candidate_model import build_model

CFG = json.load(open('/app/task_config.json'))
DEV = torch.device('cuda')

def load_split(sp):
    d = torch.load(f'/app/data/{sp}/samples.pt', weights_only=True)
    return d['features'].float(), d['labels'].float()

# ---------------- augmentation (operates on [B,2048,3] on GPU) -------------
def augment(x, cfg):
    B,N,C = x.shape
    out = x
    if cfg.get('resample',0)>0:
        # bootstrap resample points with replacement for a fraction of prob
        if torch.rand(())< cfg['resample']:
            idx = torch.randint(0,N,(B,N),device=x.device)
            out = torch.gather(out,1,idx.unsqueeze(-1).expand(-1,-1,C))
    if cfg.get('dropout',0)>0:
        # randomly duplicate points (drop some) : choose keep mask then resample dropped
        keep = (torch.rand(B,N,device=x.device) > cfg['dropout'])
        idxrand = torch.randint(0,N,(B,N),device=x.device)
        src = torch.where(keep, torch.arange(N,device=x.device).unsqueeze(0).expand(B,-1), idxrand)
        out = torch.gather(out,1,src.unsqueeze(-1).expand(-1,-1,C))
    if cfg.get('jitter',0)>0:
        out = out + torch.randn_like(out)*cfg['jitter']
    if cfg.get('scale',0)>0:
        s = cfg['scale']
        # anisotropic per-axis scale near 1
        fac = 1.0 + (torch.rand(B,1,3,device=x.device)*2-1)*s
        out = out*fac
    if cfg.get('aniso_iso',0)>0:
        s=cfg['aniso_iso']
        fac=1.0+(torch.rand(B,1,1,device=x.device)*2-1)*s
        out=out*fac
    if cfg.get('shift',0)>0:
        out = out + (torch.rand(B,1,3,device=x.device)*2-1)*cfg['shift']
    if cfg.get('rot_z',0)>0:
        ang=(torch.rand(B,device=x.device)*2-1)*cfg['rot_z']
        cz,sz=torch.cos(ang),torch.sin(ang)
        xx=out[...,0].clone(); yy=out[...,1].clone()
        out=out.clone()
        out[...,0]=cz.unsqueeze(1)*xx - sz.unsqueeze(1)*yy
        out[...,1]=sz.unsqueeze(1)*xx + cz.unsqueeze(1)*yy
    if cfg.get('mirror_x',0)>0:
        m=(torch.rand(B,1,1,device=x.device)<cfg['mirror_x']).float()*(-2)+1
        out=out.clone(); out[...,0]=out[...,0]*m.squeeze(-1)
    if cfg.get('mirror_z',0)>0:
        m=(torch.rand(B,1,1,device=x.device)<cfg['mirror_z']).float()*(-2)+1
        out=out.clone(); out[...,2]=out[...,2]*m.squeeze(-1)
    return out

def metrics(pred, true):
    pred=pred.ravel().float(); true=true.ravel().float()
    rel=(torch.linalg.norm(pred-true)/torch.linalg.norm(true)).item()
    mae=(pred-true).abs().mean().item()
    mx=(pred-true).abs().max().item()
    return rel,mae,mx

@torch.no_grad()
def predict(model, x, fm, fs, lm, ls, bs=128):
    model.eval()
    xb=(x-fm)/fs
    out=[]
    for i in range(0,x.shape[0],bs):
        out.append(model(xb[i:i+bs]))
    return torch.cat(out)*ls+lm

@torch.no_grad()
def recompute_bn(model, x, fm, fs, cfg, passes=20, bs=32):
    # reset BN running stats and recompute via forward passes (with aug)
    for m in model.modules():
        if isinstance(m, nn.BatchNorm1d):
            m.reset_running_stats(); m.momentum=None
    model.train()
    xb=(x-fm)/fs
    N=x.shape[0]
    for _ in range(passes):
        perm=torch.randperm(N,device=x.device)
        for i in range(0,N,bs):
            idx=perm[i:i+bs]
            model(xb[idx])
    model.eval()

def make_loss(name):
    if name=='mse': return lambda p,y: F.mse_loss(p,y)
    if name=='l1': return lambda p,y: F.l1_loss(p,y)
    if name.startswith('huber'):
        beta=float(name.split('_')[1]) if '_' in name else 0.1
        return lambda p,y: F.smooth_l1_loss(p,y,beta=beta)
    if name=='mse_l1':
        return lambda p,y: F.mse_loss(p,y)+0.3*F.l1_loss(p,y)
    raise ValueError(name)

def train_one(trX, trY, vaX, vaY, cfg, seed=0, verbose=False, return_model=False):
    torch.manual_seed(seed)
    fm = trX.mean(dim=(0,1),keepdim=True)
    fs = trX.std(dim=(0,1),keepdim=Tru
…[truncated]
output
trainer.py written
Now let me run a first experiment: train on train, validate on val, with a reasonable config. Let me try a few configs quickly. I'll also implement k-fold CV. Let me first do a single run to see behavior over epochs.
Now let me run a first real experiment: train on `train`, validate on `val`, with light augmentation and a cosine schedule, tracking validation over epochs.
bash
cd /app && python3 -c "
import torch
from trainer import load_split, train_one, metrics, predict, DEV
trX,trY=load_split('train'); vaX,vaY=load_split('val'); teX,teY=load_split('public_test')
trX,trY,vaX,vaY,teX,teY=[t.to(DEV) for t in (trX,trY,vaX,vaY,teX,teY)]
cfg=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',
         aug=dict(jitter=0.01,dropout=0.1,resample=0.5),
         eval_every=20,select_best=False)
r=train_one(trX,trY,vaX,vaY,cfg,seed=0,verbose=True)
print('final(last) val:', r['final_val'])
p=predict(r['model'],teX,r['fm'],r['fs'],r['lm'],r['ls'])
print('test:', metrics(p,teY))
"
output
ep0 val rel=0.4707 mae=0.3015 mx=1.3283
  ep20 val rel=0.2996 mae=0.2043 mx=0.7591
  ep40 val rel=0.3212 mae=0.2340 mx=0.5793
  ep60 val rel=0.2870 mae=0.2022 mx=0.6384
  ep80 val rel=0.2316 mae=0.1560 mx=0.5620
  ep100 val rel=0.1996 mae=0.1416 mx=0.3609
  ep120 val rel=0.1864 mae=0.1315 mx=0.3809
  ep140 val rel=0.2529 mae=0.1679 mx=0.4643
  ep160 val rel=0.1816 mae=0.1263 mx=0.3620
  ep180 val rel=0.2084 mae=0.1359 mx=0.4556
  ep200 val rel=0.1933 mae=0.1349 mx=0.3920
  ep220 val rel=0.2055 mae=0.1368 mx=0.4264
  ep240 val rel=0.1831 mae=0.1248 mx=0.3811
  ep260 val rel=0.1895 mae=0.1286 mx=0.3880
  ep280 val rel=0.1987 mae=0.1316 mx=0.4161
  ep299 val rel=0.1893 mae=0.1265 mx=0.3991
final(last) val: (0.18925225734710693, 0.12646417319774628, 0.3991163372993469)
test: (0.29615330696105957, 0.18812984228134155, 0.5778348445892334)
Good progress. With 300 epochs and light aug, val relL2 ~0.19, test ~0.30. The test is noticeably worse than val, which suggests either the test set is harder or there's variance (only 16 samples). Val improved a lot from baseline (0.47 -> 0.19). Let me now do proper cross-validation to select hyperparameters robustly, since val/test are small and noisy. I'll combine train+val (132 samples) and do 6-fold CV (22 per fold), measuring average relL2 across folds. This gives a more stable signal. Let me write a CV harness. To keep it fast, I'll use a moderate epoch count. Each run is fast on H100. Let me time one run first... the above run took some seconds. Let me build CV and test a few augmentation/loss configs. Actually, let me reconsider the metric aggregation. Rel L2 over the full set = sqrt(sum sq err)/sqrt(sum sq true). For CV, I can pool all fold predictions and compute rel L2 once over the pooled out-of-fold predictions. That's the cleanest estimate of the overall-set relL2. Similarly MAE over pooled, and max over pooled. Let me do pooled out-of-fold (OOF) predictions across all 132 samples. That's a great estimator. Let me implement k-fold OOF on train+val combined. I'll use SWA or last-epoch. Let me compare configs. Let me write a CV runner script.
Good , val relL2 improved from 0.47 to ~0.19. But val/test are small and noisy, so I'll use **k-fold cross-validation on the pooled train+val (132 samples)** with out-of-fold (OOF) predictions for a stable hyperparameter signal. Let me build that harness.
bash
cd /app && cat > /app/cv.py << 'EOF'
import torch, numpy as np, sys, json, time
from trainer import load_split, train_one, metrics, predict, DEV

def get_pool():
    trX,trY=load_split('train'); vaX,vaY=load_split('val')
    X=torch.cat([trX,vaX]).to(DEV); Y=torch.cat([trY,vaY]).to(DEV)
    return X,Y

def kfold_oof(cfg, k=6, seeds=(0,), foldseed=1234, verbose=False):
    X,Y=get_pool(); N=X.shape[0]
    g=torch.Generator().manual_seed(foldseed)
    perm=torch.randperm(N,generator=g)
    folds=[perm[i::k] for i in range(k)]
    oof=torch.zeros(N,1,device=DEV)
    for fi in range(k):
        va_idx=folds[fi].to(DEV)
        tr_idx=torch.cat([folds[j] for j in range(k) if j!=fi]).to(DEV)
        preds=[]
        for s in seeds:
            r=train_one(X[tr_idx],Y[tr_idx],X[va_idx],Y[va_idx],cfg,seed=s)
            p=predict(r['model'],X[va_idx],r['fm'],r['fs'],r['lm'],r['ls'])
            preds.append(p)
        oof[va_idx]=torch.stack(preds).mean(0)
    rel,mae,mx=metrics(oof,Y)
    if verbose: print(f'  OOF relL2={rel:.4f} mae={mae:.4f} maxabs={mx:.4f}')
    return rel,mae,mx

if __name__=='__main__':
    import itertools
    base=dict(epochs=250,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000)
    configs={
      'no_aug': {**base,'aug':{}},
      'jitter_only': {**base,'aug':{'jitter':0.01}},
      'drop_resample': {**base,'aug':{'jitter':0.01,'dropout':0.1,'resample':0.5}},
      'more_aug': {**base,'aug':{'jitter':0.015,'dropout':0.2,'resample':0.5,'shift':0.01}},
    }
    for name,cfg in configs.items():
        t=time.time()
        rel,mae,mx=kfold_oof(cfg,k=6,seeds=(0,))
        print(f'{name:16s} relL2={rel:.4f} mae={mae:.4f} maxabs={mx:.4f}  ({time.time()-t:.0f}s)')
EOF
python3 /app/cv.py
output
no_aug           relL2=0.2626 mae=0.1715 maxabs=0.6576  (38s)
jitter_only      relL2=0.2688 mae=0.1695 maxabs=0.7512  (32s)
drop_resample    relL2=0.2507 mae=0.1575 maxabs=0.7491  (34s)
more_aug         relL2=0.2635 mae=0.1645 maxabs=0.6798  (38s)
CV OOF relL2 ~0.25-0.27. The 'drop_resample' aug is best for relL2 and mae. These are pooled OOF over 132 samples, more reliable than the single val split. The single val run earlier gave 0.19 but that's optimistic/noisy. Interesting that the earlier single run got 0.19 on val but CV says ~0.25. The val split is just easier/luckier. Test was 0.30. So realistic generalization is ~0.25 relL2. Now let me improve. Ideas: 1. Ensemble multiple seeds per fold (average predictions) , reduces variance. Within CV I can test seeds=(0,1,2). For the FINAL model I can only save one model though. But I can use SWA to get ensemble-like benefit in one model. OR... wait, can I put multiple models' averaged predictions into one state_dict? No. Actually, reconsider the constraint. The checkpoint must load into PointNetRegressor. One state_dict. So one network. SWA (weight averaging along trajectory) is the way to get ensemble-like smoothing in one net. But here's another idea: I could train with more epochs and use SWA. Let me test SWA vs last vs best. 2. Tune lr, wd, epochs, architecture-compatible regularization. 3. Loss function: test huber, l1, mse_l1 for impact on mae and maxabs. Let me test seeds ensembling effect and SWA within CV. But note: for the final single model, I want the config that, when trained as a single model (with SWA), generalizes best. So in CV I should evaluate the SAME procedure I'll use finally: train_one with use_swa, single seed (since final is single model). Let me evaluate single-seed OOF with SWA vs without. However, averaging multiple seeds in CV tells me the benefit of ensembling, which I can't fully use. But SWA approximates it. Let me focus CV on single-model procedures. Let me test: - drop_resample + SWA (swa_start=150, epochs=250) - drop_resample + select_best (needs val inside; in CV the val is the fold, that's data leakage for model selection? No, select_best uses the fold's val to pick epoch, which in CV is legitimate per-fold but for FINAL model I won't have val... unless I hold out. Actually select_best uses validation to pick the best epoch. For the final model trained on all data, I won't have val. So select_best isn't directly reproducible for final. SWA or fixed-epoch is reproducible. So let me prefer SWA or fixed last-epoch.) Let me evaluate SWA in CV (single seed), and also test effect of epochs and lr/wd. Let me also test seeds=(0,1,2) averaging just to know the ceiling. Let me run a batch of experiments.
CV OOF relL2 is ~0.25 (more realistic than the lucky single val split). `drop_resample` aug looks best. Now let me test procedures I can actually reproduce in a single final model , **SWA (weight averaging)** and epoch/lr/wd choices , plus check the ceiling from multi-seed ensembling.
bash
cd /app && python3 -c "
import time
from cv import kfold_oof
base=dict(bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
          aug={'jitter':0.01,'dropout':0.1,'resample':0.5})
exps={
 'last_250': {**base,'epochs':250},
 'swa_150_300': {**base,'epochs':300,'swa_start':150,'use_swa':True},
 'swa_200_400': {**base,'epochs':400,'swa_start':200,'use_swa':True},
 'last_250_3seed': {**base,'epochs':250},
}
for name,cfg in exps.items():
    t=time.time()
    seeds=(0,1,2) if '3seed' in name else (0,)
    rel,mae,mx=kfold_oof(cfg,k=6,seeds=seeds)
    print(f'{name:18s} relL2={rel:.4f} mae={mae:.4f} maxabs={mx:.4f}  ({time.time()-t:.0f}s)')
"
output
last_250           relL2=0.2507 mae=0.1575 maxabs=0.7491  (46s)
swa_150_300        relL2=0.2468 mae=0.1537 maxabs=0.7387  (50s)
swa_200_400        relL2=0.2542 mae=0.1564 maxabs=0.7802  (77s)
last_250_3seed     relL2=0.2558 mae=0.1574 maxabs=0.7228  (109s)
SWA (150-300) gives a small improvement: relL2 0.2468 vs 0.2507. Multi-seed ensembling didn't help much here (0.2558), surprisingly , maybe because each fold has high variance. The maxabs is high ~0.74 though, driven by some hard samples. The bottleneck seems to be model capacity/representation rather than ensembling. Let me think about what's limiting. Key issue: maxabs error 0.74 is large (labels go up to 2.2). There are likely a few high-mass outliers that the model underpredicts (regression to mean). Let me look at the label distribution and the OOF errors per sample to understand where the model fails. Let me analyze the OOF residuals to understand error structure.
SWA gives a small, consistent gain. The max-abs error (~0.74) is the weak spot. Let me analyze the OOF residuals to understand *where* the model fails , likely high-mass outliers being under-predicted (regression to the mean).
bash
cd /app && python3 -c "
import torch, numpy as np
from cv import get_pool, kfold_oof
from trainer import load_split, train_one, predict, metrics, DEV
X,Y=get_pool()
# Replicate OOF to get residuals
import torch
cfg=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
         aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
N=X.shape[0]
g=torch.Generator().manual_seed(1234); perm=torch.randperm(N,generator=g)
k=6; folds=[perm[i::k] for i in range(k)]
oof=torch.zeros(N,1,device=DEV)
for fi in range(k):
    va=folds[fi].to(DEV); tr=torch.cat([folds[j] for j in range(k) if j!=fi]).to(DEV)
    r=train_one(X[tr],Y[tr],X[va],Y[va],cfg,seed=0)
    oof[va]=predict(r['model'],X[va],r['fm'],r['fs'],r['lm'],r['ls'])
y=Y.ravel().cpu().numpy(); p=oof.ravel().cpu().numpy()
err=p-y
order=np.argsort(-np.abs(err))
print('worst 10 samples (true, pred, err):')
for i in order[:10]:
    print(f'  true={y[i]:.3f} pred={p[i]:.3f} err={err[i]:+.3f}')
print()
print('correlation pred vs true:', np.corrcoef(p,y)[0,1])
# bin by true mass
for lo,hi in [(0,0.5),(0.5,0.8),(0.8,1.2),(1.2,3)]:
    m=(y>=lo)&(y<hi)
    if m.sum()>0:
        print(f'  mass[{lo},{hi}): n={m.sum():2d} meanAbsErr={np.abs(err[m]).mean():.3f} meanBias={err[m].mean():+.3f}')
"
output
worst 10 samples (true, pred, err):
  true=2.219 pred=1.480 err=-0.739
  true=0.521 pred=1.215 err=+0.695
  true=0.777 pred=1.383 err=+0.606
  true=1.366 pred=0.827 err=-0.540
  true=0.303 pred=0.796 err=+0.493
  true=1.584 pred=1.117 err=-0.467
  true=1.584 pred=1.126 err=-0.458
  true=1.619 pred=1.167 err=-0.453
  true=0.802 pred=1.217 err=+0.414
  true=0.828 pred=0.425 err=-0.403

correlation pred vs true: 0.8459989377096014
  mass[0,0.5): n=41 meanAbsErr=0.105 meanBias=+0.084
  mass[0.5,0.8): n=47 meanAbsErr=0.142 meanBias=+0.053
  mass[0.8,1.2): n=26 meanAbsErr=0.178 meanBias=-0.094
  mass[1.2,3): n=18 meanAbsErr=0.258 meanBias=-0.188
The structure is clear: - The model has correlation 0.85 with truth. - There's systematic bias: low-mass samples are over-predicted (+0.084 bias) and high-mass samples are under-predicted (-0.188 bias). This is classic regression-to-the-mean / shrinkage, worsened by the squared loss on standardized labels and limited model expressiveness. - The worst errors are the extreme-mass samples. To reduce both relL2 and maxabs, I need to reduce this shrinkage, especially improving prediction on high-mass (chunky) brackets. Ideas to reduce shrinkage/bias: 1. The label distribution is right-skewed (mass 0.2 to 2.2, mean 0.75). Predicting in log space might help , log-mass is more symmetric, and relative errors get more uniform treatment. But the metric is on linear mass. Still, training on log could reduce bias for large values. Let me test log-target. 2. Better shape features: the under-prediction of heavy brackets suggests the model can't capture "solidity/volume" well with max-pooling. Heavy brackets are more solid/filled. Max-pool sees extent but not fill. Hmm. Wait , but the input is SURFACE points normalized to unit cube. Two brackets with same silhouette but different thickness... Actually heavier = more material = thicker features. On the surface sampling, a thicker bracket has points distributed differently. But max-pool may not capture volume. However, the correlation is 0.85 which is decent. The main issue is calibration (shrinkage). 3. A simple but effective fix for shrinkage: post-hoc linear calibration. Fit pred_calibrated = a*pred + b on a held-out set to undo shrinkage. But the shrinkage is multiplicative toward the mean; a linear calibration with a>1 would expand predictions. However, I can't add calibration as a separate step at inference , wait, actually I CAN fold a linear calibration into the model! The final head layer is Linear(64,1), and the de-standardization is pred*ls+lm. If I want to apply pred_cal = a*pred+b, I can bake 'a' and 'b' into label_std and label_mean: since output_physical = model_out * label_std + label_mean. If I scale label_std by a and adjust label_mean, I get a*model_out*ls + (a*... ). Actually: physical = model_out * ls + lm. I want physical_new = a*physical + b = a*(model_out*ls+lm)+b = model_out*(a*ls) + (a*lm+b). So set label_std' = a*ls, label_mean' = a*lm + b. So I can apply ANY affine calibration by modifying label_mean/label_std! That's powerful and fully within the allowed checkpoint format. But wait, would the grader use my label_mean/label_std exactly? Yes: "label_mean, label_std ... The model's output is mapped back to physical units using these." So physical = out*label_std + label_mean. I can choose these freely. But careful: label_mean/label_std are also "used to standardize the target during training". The grader doesn't re-train; it only uses them for de-standardization. So I'm free to set them to calibrated values. However, this is a bit of a hack and if the grader checks that they equal the train label stats, it might be flagged , but the spec only says they're used for de-standardization at inference. I'll use the natural stats for training, but I could optionally bake calibration. Let me keep this in mind as a lever, but first try to fix shrinkage more fundamentally (log-space, loss). Actually, a cleaner approach to reduce shrinkage during training: the shrinkage comes partly from MSE + regularization + limited capacity. Training longer / less regularization reduces bias but increases variance. Let me test log-target which often helps skewed regression. Let me also reconsider: maybe the issue is that relL2 weights large-mass samples more (since it's absolute squared error, large masses dominate the numerator AND denominator). The heavy samples have large absolute errors, dominating relL2. So fixing heavy-sample prediction is key for relL2. Let me test: A) log-target training B) post-hoc linear calibration (debias) applied to OOF to see potential gain. Let m …[truncated]
The model shows classic shrinkage: low-mass over-predicted, high-mass under-predicted (correlation 0.85 but miscalibrated). The heavy brackets dominate relL2. A key realization: since physical output = `model_out * label_std + label_mean`, I can fold **any affine calibration** into `label_mean`/`label_std`. Let me first measure the ceiling from debiasing, and test log-space training which often helps skewed targets.
bash
cd /app && python3 -c "
import torch, numpy as np
from cv import get_pool
from trainer import train_one, predict, metrics, DEV
X,Y=get_pool(); N=X.shape[0]
def run_oof(cfg,seed=0,logspace=False):
    g=torch.Generator().manual_seed(1234); perm=torch.randperm(N,generator=g)
    k=6; folds=[perm[i::k] for i in range(k)]
    oof=torch.zeros(N,1,device=DEV)
    for fi in range(k):
        va=folds[fi].to(DEV); tr=torch.cat([folds[j] for j in range(k) if j!=fi]).to(DEV)
        Ytr = Y[tr].log() if logspace else Y[tr]
        r=train_one(X[tr],Ytr,X[va],(Y[va].log() if logspace else Y[va]),cfg,seed=seed)
        p=predict(r['model'],X[va],r['fm'],r['fs'],r['lm'],r['ls'])
        if logspace: p=p.exp()
        oof[va]=p
    return oof
cfg=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
         aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
oof=run_oof(cfg)
y=Y.ravel(); p=oof.ravel()
print('baseline     ', tuple(round(v,4) for v in metrics(p,y)))
# linear calibration ceiling (fit on same data = optimistic upper bound)
A=torch.stack([p,torch.ones_like(p)],1)
coef=torch.linalg.lstsq(A,y.unsqueeze(1)).solution.ravel()
pc=coef[0]*p+coef[1]
print(f'lin-calib a={coef[0]:.3f} b={coef[1]:.3f}:', tuple(round(v,4) for v in metrics(pc,y)))
# log-space training
oofl=run_oof(cfg,logspace=True)
print('logspace     ', tuple(round(v,4) for v in metrics(oofl.ravel(),y)))
"
output
baseline      (0.2468, 0.1537, 0.7387)
lin-calib a=0.987 b=0.009: (0.2468, 0.1537, 0.7493)
logspace      (0.2711, 0.1679, 0.7883)
Interesting findings: - Linear calibration globally gives a≈0.99, b≈0.009 → basically no global linear debiasing helps. The bias is nonlinear (conditional on mass level), so a single global linear fit can't fix it. The shrinkage is conditional , it's about the model not being able to distinguish heavy from light well enough, not a simple global scale. So the correlation ceiling is the limiter. - Log-space training is WORSE (0.271). So linear MSE is better for this linear metric. So the real lever is improving the model's discriminative power (correlation), especially for heavy brackets. The max-pool PointNet may be fundamentally limited at capturing "volume/solidity." Let me think about what additional signal could help within the constraints. The input is just coordinates. But I can choose feat_mean/feat_std (per-axis affine). That doesn't add features. Wait , actually, is there a way to give the network more useful information through the normalization? No, only affine per-axis. Hmm. Let me reconsider the architecture. The forward is: x = points.transpose -> [B,3,N] feature: shared MLP 3->64->64->64 lift: 64->128->256 max over N -> [B,256] head -> 1 This is a standard PointNet. Its global feature is max-pooled. Max-pooling captures, for each of 256 channels, the maximum activation across points , i.e., "is there a point that strongly activates this feature detector". This gives a silhouette/extent-like descriptor. It does NOT directly count points or measure density/volume. For mass ∝ volume, the key missing ingredient is volume/density. But on a normalized-to-unit-cube surface cloud, can volume be inferred? The heavier brackets are more "filled". With uniform surface sampling of 2048 points, a more complex/larger surface area gets... wait, all have exactly 2048 points regardless of surface area. So point density per unit area varies: a bracket with large surface area has sparser sampling. Density could encode surface area, which relates to volume. But max-pool can't measure density. However, I can't change the architecture. So I must extract as much as possible with max-pool. The max-pool can still capture the spatial EXTENT of the shape in many learned directions (essentially a support function / convex description), plus presence of geometric features. For brackets that differ mainly in thickness/filling, extent-based features partially capture it (thicker = larger extent in some direction). Given correlation 0.85 and the conditional bias, maybe I can push correlation higher with a better-tuned model. Let me explore: 1. Larger effective training (the architecture is fixed, but training schedule matters). 2. Different aug , maybe the aug is limiting. Let me test no aug vs aug on the SWA setup more carefully with multiple fold-seeds to reduce noise. 3. More importantly: the CV estimate itself is noisy (one fold split). Let me average over multiple fold seeds to get a reliable comparison. Otherwise I'm tuning to noise. Let me make the CV more robust by averaging over 2-3 fold partitions. This is crucial to avoid chasing noise. Let me re-run key configs with repeated CV. Let me also reconsider maxabs: the single worst sample (true=2.219, the heaviest) is always going to be hard since it's an extreme. relL2 is dominated by it too. Let me focus on a robust comparison with repeated CV for a few promising configs, including tuning lr/wd/epochs and aug strength. Let me write a repeated-CV function. Actually, given compute (each 6-fold run ~50s), repeated 3x = 150s per config. Manageable. Let me be selective. Let me test the impact of: - wd (regularization): 1e-4 vs 3e-4 vs 1e-3 vs 5e-5 - aug strength with repeated CV (3 fold-seeds), using the SWA procedure. Let me build repeated CV.
Key insights: a *global* linear calibration barely helps (a≈0.99) , the bias is conditional, so the real lever is the model's discriminative power. Log-space is worse. My single-partition CV is noisy, so I must average over multiple fold partitions to avoid tuning to noise. Let me build repeated CV and sweep regularization (weight decay), which most directly trades bias vs. variance here.
bash
cd /app && cat > /app/rcv.py << 'EOF'
import torch, numpy as np
from cv import get_pool
from trainer import train_one, predict, metrics, DEV
X,Y=get_pool(); N=X.shape[0]
def rep_oof(cfg, fold_seeds=(1234,99,7), k=6, seed=0):
    rels=[];maes=[];mxs=[]; allp=[];ally=[]
    for fs_ in fold_seeds:
        g=torch.Generator().manual_seed(fs_); perm=torch.randperm(N,generator=g)
        folds=[perm[i::k] for i in range(k)]
        oof=torch.zeros(N,1,device=DEV)
        for fi in range(k):
            va=folds[fi].to(DEV); tr=torch.cat([folds[j] for j in range(k) if j!=fi]).to(DEV)
            r=train_one(X[tr],Y[tr],X[va],Y[va],cfg,seed=seed)
            oof[va]=predict(r['model'],X[va],r['fm'],r['fs'],r['lm'],r['ls'])
        rel,mae,mx=metrics(oof.ravel(),Y.ravel())
        rels.append(rel);maes.append(mae);mxs.append(mx)
    return (np.mean(rels),np.std(rels)),(np.mean(maes)),(np.mean(mxs))
EOF
python3 -c "
from rcv import rep_oof
base=dict(epochs=300,bs=16,lr=1e-3,warmup=10,loss='mse',eval_every=1000,
          aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
for wd in [5e-5,1e-4,3e-4,1e-3]:
    cfg={**base,'wd':wd}
    (rel,std),mae,mx=rep_oof(cfg)
    print(f'wd={wd:.0e}: relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}')
"
output
[stderr]
Shell command timed out.
Tool interaction exceeded 300 seconds.
The repeated CV over 4 wd values * 3 fold-seeds * 6 folds * 300 epochs timed out (>300s). I need to run in background and poll, or reduce scope. Let me restart the tool and run experiments in the background, writing results to a file.
The repeated sweep exceeded the 300s limit. Let me restart and run experiments in the background, logging to files so I can poll without blocking.
bash
restart: true
output
<system>tool has been restarted.</system>
bash
cd /app && cat > /app/exp_wd.py << 'EOF'
from rcv import rep_oof
base=dict(epochs=300,bs=16,lr=1e-3,warmup=10,loss='mse',eval_every=1000,
          aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
for wd in [5e-5,1e-4,3e-4,1e-3]:
    cfg={**base,'wd':wd}
    (rel,std),mae,mx=rep_oof(cfg)
    print(f'wd={wd:.0e}: relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}',flush=True)
EOF
nohup python3 /app/exp_wd.py > /app/exp_wd.log 2>&1 &
echo "started PID $!"
output
started PID 315
Let me wait and poll. Meanwhile, let me think about other improvements while this runs. Let me poll periodically.
While that runs, let me reflect on the bigger picture. The model is limited by discriminative power on heavy brackets. Let me poll the weight-decay sweep as it progresses.
bash
cd /app && sleep 180 && cat /app/exp_wd.log
output
wd=5e-05: relL2=0.2476+-0.0034 mae=0.1546 maxabs=0.7013
Each wd value takes ~180s (3 fold-seeds * 6 folds * 300 epochs). So 4 values = ~12 min. The repeated CV gives a stable estimate: relL2=0.2476 +- 0.0034. Good, low std now. Let me wait for the rest. Meanwhile let me think more. The relL2 ~0.247 seems to be a plateau around wd variations. Let me consider more impactful changes: 1. Test-time augmentation (TTA): At inference, the grader runs model(x) once per sample with the fixed normalization. I can't control inference to do TTA. So no TTA at grading time. Unless... the model itself does internal augmentation? No. So TTA is out. 2. Since I can bake an affine into label_mean/label_std, and global linear calibration doesn't help, that lever is weak. 3. The fundamental limiter is the max-pool PointNet's ability to regress volume/mass. Let me verify the ceiling: train on ALL 132 and evaluate on the same data (train error) to see if the model even has capacity to fit. If train error is also ~0.2, it's underfitting (capacity/representation limit). If train error is near 0, it's overfitting (variance limit) and I should regularize/ensemble. Let me check train-fit capacity once the sweep frees up. Actually let me run it in parallel-ish after. Let me wait for the sweep. Let me think about the representation limit. Actually, maybe I can help the network by a better input normalization. The allowed transform is per-axis (x-mean)/std. The current global std is ~[0.14,0.27,0.087]. After dividing, all axes become comparable scale. That's fine. But what if a coordinate-based feature expansion would help? I cannot change the architecture's first layer (Conv1d(3,64)). Input must be 3-dim. So no feature expansion. Hold on , let me reconsider whether I truly cannot exploit the scale. The bounding box max-extent is always 1. But the OTHER two extents vary per sample and encode aspect ratio. The network can capture these via max-pool (max of x = half-extent if centered). So aspect ratio IS available. Good. What else correlates with mass? The "chunkiness". Consider the distribution of points: a solid chunky bracket vs a thin strut bracket. With 2048 surface points, the chunky one has points more spread through the volume's surface. Max-pool captures extent but the head sees only the 256-dim max-pooled vector. I think the representation is the limit. Let me see if a much longer training / different capacity usage helps, or if I'm at the data limit (132 samples is just few). Actually, one more idea: the labels are FEA mass. Mass = density × volume. If all brackets are the same material (same density), mass ∝ volume. Volume of a normalized-to-unit-box shape. The network should estimate normalized volume × (scale factor)³ × density. But scale factor is removed! So we rely on the design-envelope assumption. Hmm wait , actually this is the crux. If bracket A is a scaled-up version of bracket B (same normalized shape), they'd have the same normalized point cloud but different mass (by scale³). If the dataset contains such cases, mass is fundamentally unpredictable from normalized shape → irreducible error. The correlation of 0.85 and relL2 0.25 might be near the irreducible limit imposed by scale normalization. Let me test this hypothesis: find pairs of samples with very similar normalized point clouds but different mass. If they exist, that's irreducible error. Let me compute a shape-distance between samples (e.g., via sorted coordinate distributions or Chamfer approx) and see if similar shapes have similar mass. Actually, a simpler check: the simple geometric-feature regressor got relL2 0.29, PointNet gets 0.247. Let me estimate the irreducible noise by looking at nearest-neighbor mass consistency. For each sample, find its nearest neighbor in shape space; if masses differ a lot even for near-identical shapes, that's the floor. Let me do a shape-NN analysis using a permutation-invariant shape descriptor. A decent descriptor: sort each axis's coordinates and compare (captures marginal dis …[truncated]
relL2 ≈ 0.247 ± 0.003 , nicely stable now. Let me wait for the remaining weight-decay values.
bash
cd /app && sleep 200 && cat /app/exp_wd.log
output
wd=5e-05: relL2=0.2476+-0.0034 mae=0.1546 maxabs=0.7013
wd=1e-04: relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
wd=1e-4 gives 0.2421, slightly better than 5e-5. Let me wait for the remaining two (3e-4, 1e-3). Meanwhile, let me prepare the irreducible-error analysis to understand the data floor. I'll run it after the sweep finishes to avoid contention (though GPU can handle parallel, the CPU is limited to 3 cores; the training is GPU-bound so I could run the analysis now). Let me run a quick shape-neighbor analysis in parallel , it's mostly GPU too. Actually let me just wait to keep logs clean, it's only a few minutes. Let me think about the final model training strategy while waiting: Final model options: 1. Train on all 132 (train+val) , or even 148 (including public_test) since none is the grading set. Using more data generally helps. But public_test is my only "fresh" eval proxy. If I train on it too, I lose that proxy. Given CV already gives me a robust estimate, I could fold public_test into training for the final model to maximize data. But I'd want to keep CV-based hyperparameters. Actually, the cleanest: select hyperparameters via repeated CV on the 132. Then for the FINAL model, train on all 148 samples (train+val+public_test) using those hyperparameters and SWA (no early stopping needed). This maximizes training data. I'll verify the final model's sanity by checking it doesn't do something crazy, but I can't hold out from it. Alternatively train on 132 and eval on public_test(16) as a final sanity check, then optionally retrain on 148. I think the safest high-value move: final model trained on all 148 with SWA. More data = better. Let me confirm the CV hyperparameters first. 2. Ensemble via SWA is baked in. Let me wait for sweep.
wd=1e-4 is best so far (0.2421). Let me wait for the last two values.
bash
cd /app && sleep 200 && cat /app/exp_wd.log
output
wd=5e-05: relL2=0.2476+-0.0034 mae=0.1546 maxabs=0.7013
wd=1e-04: relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
wd=3e-04: relL2=0.2438+-0.0069 mae=0.1542 maxabs=0.6611
wd=3e-4: 0.2438 (similar, slightly lower maxabs 0.66). Let me wait for wd=1e-3 and then move on. wd=1e-4 and 3e-4 are both good. 3e-4 gives better maxabs. Let me consider the tradeoff , the primary metric is relL2, and 1e-4 gives 0.2421 vs 3e-4 gives 0.2438 (within noise ±0.005-0.007). 3e-4 gives notably better maxabs (0.661 vs 0.699). Since I shouldn't trade off metrics, 3e-4 might be a good balance. Let me wait for the last one. Meanwhile let me now run the irreducible-error / shape-neighbor analysis to understand the floor. Let me start it in the background now.
Let me launch the irreducible-error analysis now (to understand the data floor from scale normalization) while the last wd value finishes.
bash
cd /app && cat > /app/floor.py << 'EOF'
import torch, numpy as np
from cv import get_pool
from trainer import DEV
X,Y=get_pool()  # [132,2048,3], [132,1]
y=Y.ravel()
# Permutation-invariant shape descriptor: per-axis sorted quantiles + covariance eigenvalues + extents
def descr(f):
    outs=[]
    qs=torch.linspace(0,1,33,device=f.device)
    for i in range(f.shape[0]):
        p=f[i]
        ext=p.max(0).values-p.min(0).values
        c=p-p.mean(0,keepdim=True)
        cov=(c.T@c)/p.shape[0]
        ev=torch.linalg.eigvalsh(cov)
        quant=torch.quantile(p,qs,dim=0).T.reshape(-1)  # 3*33
        outs.append(torch.cat([ext,ev,quant]))
    return torch.stack(outs)
D=descr(X)
D=(D-D.mean(0))/(D.std(0)+1e-8)
# pairwise dist
dist=torch.cdist(D,D)
dist.fill_diagonal_(1e9)
nn=dist.argmin(1)
# nearest-neighbor mass difference
nn_err=(y-y[nn]).abs()
print('NN shape -> mass |Δmass|: mean=%.4f median=%.4f'%(nn_err.mean(),nn_err.median()))
print('relL2 if predict NN mass:', (torch.linalg.norm(y-y[nn])/torch.linalg.norm(y)).item())
# k=3 NN average prediction
k=3
idx=dist.topk(k,largest=False).indices
pk=y[idx].mean(1)
print(f'relL2 if predict {k}-NN avg mass:', (torch.linalg.norm(pk-y)/torch.linalg.norm(y)).item())
print(f'mae {k}-NN: %.4f maxabs %.4f'%((pk-y).abs().mean(),(pk-y).abs().max()))
EOF
nohup python3 /app/floor.py > /app/floor.log 2>&1 &
echo "started $!"
output
started 354
bash
cd /app && sleep 60 && echo "=== wd sweep ===" && cat /app/exp_wd.log && echo "=== floor (shape-NN) ===" && cat /app/floor.log
output
=== wd sweep ===
wd=5e-05: relL2=0.2476+-0.0034 mae=0.1546 maxabs=0.7013
wd=1e-04: relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
wd=3e-04: relL2=0.2438+-0.0069 mae=0.1542 maxabs=0.6611
wd=1e-03: relL2=0.2472+-0.0046 mae=0.1563 maxabs=0.6901
=== floor (shape-NN) ===
NN shape -> mass |Δmass|: mean=0.2361 median=0.1895
relL2 if predict NN mass: 0.3830491006374359
relL2 if predict 3-NN avg mass: 0.32402941584587097
mae 3-NN: 0.2102 maxabs 0.8651
The shape-NN analysis: using my hand-crafted descriptor, nearest-neighbor mass prediction gives relL2 0.38, worse than PointNet (0.24). So my descriptor isn't as good as PointNet, which makes sense. But the NN |Δmass| mean of 0.236 suggests that even similar-shaped brackets (by this descriptor) differ in mass by ~0.24 on average , though this descriptor may not capture true shape similarity well. So this doesn't cleanly establish an irreducible floor; it just shows my descriptor is weaker than PointNet. The wd sweep: all wd in [1e-4, 3e-4] give ~0.242-0.244. wd=1e-4 best relL2, wd=3e-4 best maxabs. The model is plateaued around relL2 0.242. Let me now check the training-fit capacity (does it overfit or underfit?) to decide direction. Let me train on all 132 and measure in-sample error. If in-sample relL2 << 0.24, it overfits → more regularization/ensembling/data. If in-sample ≈ 0.24, it underfits → need better representation (but architecture is fixed) or it's the data floor. Let me run that. Also let me reconsider: maybe the aug is too weak or too strong. And maybe more careful: the model trained per-fold on 110 samples; the final on 132 or 148 will be better. CV underestimates final performance slightly because final uses more data. Let me test in-sample fit and also whether removing aug lets it fit better (capacity check). Quick single runs.
The wd sweep plateaus at ~0.242 (wd=1e-4 best relL2, 3e-4 best max-abs). My hand-crafted shape-NN is weaker than PointNet, so it doesn't pin the floor. Let me check whether the model is **over- or under-fitting** by measuring in-sample error vs CV error , this decides my next move.
bash
cd /app && timeout 250 python3 -c "
import torch
from cv import get_pool
from trainer import train_one, predict, metrics, DEV
X,Y=get_pool()
# Train on all 132, measure in-sample fit, with and without aug
for tag,aug in [('with_aug',{'jitter':0.01,'dropout':0.1,'resample':0.5}),('no_aug',{})]:
    cfg=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,aug=aug,swa_start=150,use_swa=True)
    r=train_one(X,Y,X,Y,cfg,seed=0)
    p=predict(r['model'],X,r['fm'],r['fs'],r['lm'],r['ls'])
    print(f'{tag:10s} in-sample:', tuple(round(v,4) for v in metrics(p,Y.ravel())))
"
output
with_aug   in-sample: (0.0647, 0.0416, 0.1868)
no_aug     in-sample: (0.0421, 0.028, 0.0973)
In-sample relL2 is 0.065 (with aug) / 0.042 (no aug), while CV is ~0.24. So the model clearly OVERFITS , it can fit training data to relL2 0.04-0.06 but generalizes to 0.24. This is a variance problem, not capacity/representation. This is good news: it means ensembling, more data, and stronger regularization could help close the gap. The aug reduces overfitting (in-sample 0.065 vs 0.042) and helps generalization slightly. Strategies to reduce variance (overfitting): 1. Stronger augmentation , makes training harder, reduces memorization. Let me sweep aug strength more aggressively. 2. More data for final model (148 vs 132) , modest help. 3. Ensembling , SWA helps a bit. True multi-model ensembling would help more but can't fit in one state_dict. BUT WAIT. Can I be clever about the single-architecture constraint? The constraint is the checkpoint loads into PointNetRegressor. What if I train an ensemble and distill it into a single PointNetRegressor? Knowledge distillation: train K diverse models (ensemble), generate smoothed predictions on training data (and augmented copies), then train a single PointNetRegressor to match the ensemble's predictions. The distilled model can capture much of the ensemble's generalization in one network. This is a legitimate and powerful approach within the constraint! Even better: I can generate a LOT of augmented training examples, label them with the ensemble's averaged prediction, and train the student on this large smoothed dataset. This regularizes the student toward the ensemble's generalization. Actually, simpler and very effective for variance reduction: train many models on bootstrap/different seeds, and do a form of "ensemble distillation." Let me first quantify how much a true multi-model ensemble helps (the ceiling), via CV where each fold's prediction is averaged over many seeds. Earlier 3-seed gave 0.2558 (but that was a different single fold-seed and config). Let me measure ensemble benefit properly with repeated CV. 4. Stronger regularization via aug is the cheapest. Let me sweep aug strength. Let me prioritize: A) Measure multi-seed ensemble benefit (repeated CV, seeds=(0,1,2,3,4) averaged). If substantial, pursue distillation. B) Sweep aug strength. Let me do A quickly but it's expensive (5x training per fold). Let me do a moderate version: repeated CV with 1 fold-seed but 5 seeds averaged, vs 1 seed, to measure ensemble gain. Actually I already have single-fold numbers. Let me just run one fold-seed with 5-seed ensembling vs 1 seed on the same partition for a clean comparison. Let me run these in background to avoid timeout.
The model **overfits** heavily: in-sample relL2 ≈ 0.05 but CV ≈ 0.24. This is a variance problem, so ensembling, stronger augmentation, and more data should help. Since I can only save one network, I'll test two levers: (1) how much a multi-seed ensemble helps (the ceiling I'd target via **distillation**), and (2) stronger augmentation. Let me run both in the background.
bash
cd /app && cat > /app/exp_ens.py << 'EOF'
import torch, numpy as np
from cv import get_pool
from trainer import train_one, predict, metrics, DEV
X,Y=get_pool(); N=X.shape[0]
def oof_ens(cfg, nseed, fold_seed=1234, k=6):
    g=torch.Generator().manual_seed(fold_seed); perm=torch.randperm(N,generator=g)
    folds=[perm[i::k] for i in range(k)]
    oof=torch.zeros(N,1,device=DEV)
    for fi in range(k):
        va=folds[fi].to(DEV); tr=torch.cat([folds[j] for j in range(k) if j!=fi]).to(DEV)
        ps=[]
        for s in range(nseed):
            r=train_one(X[tr],Y[tr],X[va],Y[va],cfg,seed=s)
            ps.append(predict(r['model'],X[va],r['fm'],r['fs'],r['lm'],r['ls']))
        oof[va]=torch.stack(ps).mean(0)
    return metrics(oof.ravel(),Y.ravel())
cfg=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
         aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
for ns in [1,3,8]:
    m=oof_ens(cfg,ns)
    print(f'ensemble nseed={ns}: relL2={m[0]:.4f} mae={m[1]:.4f} maxabs={m[2]:.4f}',flush=True)
EOF
nohup python3 /app/exp_ens.py > /app/exp_ens.log 2>&1 &
echo "ens PID $!"
output
ens PID 392
bash
cd /app && cat > /app/exp_aug.py << 'EOF'
from rcv import rep_oof
base=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,swa_start=150,use_swa=True)
augs={
 'base': {'jitter':0.01,'dropout':0.1,'resample':0.5},
 'strong_drop': {'jitter':0.015,'dropout':0.3,'resample':0.8},
 'with_aniso': {'jitter':0.01,'dropout':0.2,'resample':0.8,'scale':0.1},
 'with_rotz': {'jitter':0.01,'dropout':0.2,'resample':0.8,'rot_z':0.1},
 'with_mirrorx': {'jitter':0.01,'dropout':0.2,'resample':0.8,'mirror_x':0.5},
}
for name,aug in augs.items():
    cfg={**base,'aug':aug}
    (rel,std),mae,mx=rep_oof(cfg, fold_seeds=(1234,99))
    print(f'{name:14s} relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}',flush=True)
EOF
echo "aug exp ready (will run after ens)"
output
aug exp ready (will run after ens)
Let me wait for the ensemble experiment to finish (it has 1+3+8=12 full 6-fold runs, which is ~ (12/1)*... each 6-fold run with SWA is ~50s, so 12 runs = ~10 min). Let me poll. While waiting, let me think about the mirror augmentation validity. SimJEB brackets: the loading/mounting interface has specific symmetry. Many brackets are symmetric about a plane. If the bracket is symmetric about the x=0 plane (left-right), then mirroring x is a valid augmentation that preserves the shape distribution and mass. But not all brackets are symmetric. Mirroring a non-symmetric bracket produces a new valid-looking bracket with the SAME mass (mass is invariant to reflection). So mirror augmentation generates plausible new shapes with known mass , this is a GREAT augmentation for increasing effective data, as long as the test distribution could include such reflections or the reflected shapes are "in-distribution enough" to help learning the shape→mass map. Even if reflected shapes aren't exactly in the test distribution, reflection-invariance is a true property of mass (mass doesn't change under reflection), so enforcing it should help generalization without bias. Actually, mass is invariant under ANY rigid transformation (rotation, reflection, translation) AND the normalized point cloud... wait, no. The normalization (fit bounding box to unit cube) is applied BEFORE we get the data. Reflection commutes with axis-aligned bounding box normalization (reflecting about a coordinate plane maps the AABB to itself reflected, same extents). So a reflected normalized cloud is the same as the normalized reflected cloud. And mass is reflection-invariant. So mirror augmentation along any axis is a PERFECT label-preserving augmentation. This should be very helpful. Rotation by 90° about axes would also preserve mass, but changes which axis is longest → changes normalization (the bounding box renormalizes). Actually a 90° rotation swaps axes; after renormalization to unit cube, the shape would be re-scaled differently. Since the data is always oriented with y as long axis, a 90° rotation would put a different axis as long, which is OUT of distribution (test data presumably keeps canonical orientation). So avoid big rotations. Small rotations about z (in-plane) might help robustness but change bbox slightly. Let me rely on the experiment. Mirror along x (the medium axis) and z (the short axis) preserve the canonical orientation (y stays long). These are likely valid and in-distribution. Mirror along y would keep y as long axis too (just flips top-bottom) , also valid. Let me test mirror_x primarily, and could combine. Let me wait for experiments. Let me poll the ensemble log.
Note: reflecting a point cloud about a coordinate plane commutes with axis-aligned-bbox normalization and leaves mass unchanged , so **mirror augmentation is a label-preserving, in-distribution way to expand the tiny dataset**. My aug sweep tests this. Let me poll the ensemble experiment first.
bash
cd /app && sleep 210 && cat /app/exp_ens.log
output
ensemble nseed=1: relL2=0.2468 mae=0.1537 maxabs=0.7387
nseed=1 done (0.2468, matches earlier). nseed=3 and 8 still running. Let me wait more.
bash
cd /app && sleep 240 && cat /app/exp_ens.log
output
ensemble nseed=1: relL2=0.2468 mae=0.1537 maxabs=0.7387
ensemble nseed=3: relL2=0.2567 mae=0.1569 maxabs=0.7123
Interesting , ensemble nseed=3 gives 0.2567, WORSE than nseed=1 (0.2468) on this fold-seed. That's surprising. Ensembling multiple seeds isn't helping and may hurt slightly. This suggests the variance between seeds is not the dominant issue, OR the SWA already captures the benefit, OR there's something about this particular fold partition. Wait, this is just one fold-seed (1234), so noise. But the fact that 3-seed ensemble is worse than 1-seed on the same partition is notable , averaging should reduce variance. Unless the individual SWA models are already low-variance and the difference is the fold noise... but it's the SAME fold partition, so fold noise is identical. The only difference is seeds. 3-seed avg should be >= 1-seed in expectation for variance reduction. Getting worse suggests the seed-0 model happened to be good on this partition, and averaging regressed it. This is within noise. Let me wait for nseed=8 which should be the most stable. If 8-seed isn't better than 1-seed, then multi-model ensembling (and hence distillation) won't help much, and I should focus elsewhere (augmentation, data). Let me reconsider. The overfitting gap (in-sample 0.05 vs CV 0.24) is huge, but ensembling isn't closing it. That means the error isn't from high-variance "jitter" around a good predictor that averaging fixes , it's more systematic: each model generalizes to ~0.24 because the problem is genuinely hard (limited info / data). The models make CORRELATED errors (they all under-predict the same heavy brackets), so averaging doesn't help. This points back to: the task has substantial irreducible error from scale normalization, OR the shape→mass signal is just hard with 132 samples. If errors are correlated across seeds, distillation won't beat a single model. So I should focus on: 1. Best single-model training (regularization, aug, data). 2. More data (train on 148 for final). Let me wait for nseed=8 to confirm, then pivot to augmentation sweep (especially mirror, which adds genuine new information via label-preserving symmetry). Let me wait.
bash
cd /app && sleep 200 && cat /app/exp_ens.log
output
ensemble nseed=1: relL2=0.2468 mae=0.1537 maxabs=0.7387
ensemble nseed=3: relL2=0.2567 mae=0.1569 maxabs=0.7123
bash
cd /app && sleep 120 && cat /app/exp_ens.log && echo "--- proc ---" && ps aux | grep -c "[e]xp_ens"
output
ensemble nseed=1: relL2=0.2468 mae=0.1537 maxabs=0.7387
ensemble nseed=3: relL2=0.2567 mae=0.1569 maxabs=0.7123
--- proc ---
1
nseed=8 still running (8 models per fold * 6 folds = 48 SWA trainings, ~ a few more min). Let me wait a bit more. Meanwhile I'm fairly convinced ensembling won't dramatically help given nseed=3 was worse. Let me wait for the final number then launch the aug sweep.
bash
cd /app && sleep 150 && cat /app/exp_ens.log && echo "--- running? ---" && ps aux | grep -c "[e]xp_ens"
output
ensemble nseed=1: relL2=0.2468 mae=0.1537 maxabs=0.7387
ensemble nseed=3: relL2=0.2567 mae=0.1569 maxabs=0.7123
ensemble nseed=8: relL2=0.2606 mae=0.1585 maxabs=0.7294
--- running? ---
0
Confirmed: ensembling does NOT help (nseed=8 gives 0.2606, worse than nseed=1's 0.2468). The errors are highly correlated across seeds , averaging doesn't reduce the systematic error. This means: - The bottleneck is systematic (data/representation limited), not variance from initialization. - Distillation from an ensemble won't help. - SWA already provides whatever smoothing benefit exists. So I should focus on: 1. Augmentation , especially label-preserving mirror (adds genuine symmetry information), which could effectively enlarge the dataset and reduce systematic error. 2. Using more data for the final model (148 samples). 3. Good single-model regularization. Let me run the augmentation sweep now. Actually, wait. Let me reconsider the ensemble result more carefully. nseed increasing monotonically makes it WORSE (0.2468 -> 0.2567 -> 0.2606). That's strange , more averaging making it consistently worse is not just noise. Oh! I think I understand. With SWA, each individual model is already a averaged, smooth, low-variance, well-calibrated predictor. Averaging multiple SWA models' PREDICTIONS shrinks toward the mean MORE (averaging reduces the spread of predictions → more regression to mean → worse on the extreme heavy brackets that dominate relL2). Since the dominant error is under-prediction of heavy brackets, any additional shrinkage (from averaging) makes relL2 worse. That's consistent with the monotonic worsening. This tells me the model is UNDER-confident on extremes (too much shrinkage). I want LESS shrinkage, not more. So I should: - Reduce regularization that causes shrinkage? But that increases variance/overfitting. - Train in a way that preserves the extremes. Hmm, but earlier wd sweep showed wd=1e-4 better than 5e-5. And no-aug overfit more. There's tension. Let me reconsider the shrinkage. The MSE loss on standardized targets naturally shrinks predictions toward the mean when the model is uncertain. One way to reduce shrinkage on extremes: weight the loss by target magnitude, or use a loss that penalizes under-prediction of large values more. But that could hurt overall. Actually, the cleanest lever for relL2 specifically: relL2 = ||pred-true||/||true||. The gradient of relL2² w.r.t. pred_i is proportional to (pred_i - true_i)/||true||². This is just MSE. So MSE is the right loss for relL2 (up to constant). No per-sample reweighting needed for relL2. The shrinkage is a property of the bias-variance tradeoff under limited data. To reduce it, I can: 1. Calibrate to expand predictions (multiply by factor >1). But earlier global linear calib gave a=0.987 (slight shrink!), meaning on average predictions are NOT globally shrunk , the shrinkage is conditional (only at extremes). A global expansion would overshoot the middle. 2. A piecewise/nonlinear calibration could help the extremes. But risky to fit on limited data and might not generalize; also I can only bake an AFFINE transform into label_mean/std. Non-affine calibration can't be baked into the checkpoint (inference only does out*ls+lm). So affine only. Given global affine doesn't help (a≈0.99), calibration is out. So the path forward is mainly: best single model + good augmentation + more data. Let me run the aug sweep (with mirror) and see if mirror helps. The mirror augmentation genuinely creates new shapes with exact labels, which could reduce the systematic error by teaching the model the true shape→mass relationship more robustly. Let me run the aug sweep now (2 fold-seeds for speed).
Ensembling consistently *worsens* relL2 (0.247→0.261) , errors are systematic/correlated, and extra averaging adds shrinkage that hurts the heavy brackets dominating relL2. So distillation won't help; the levers are **augmentation, more data, and a well-regularized single model**. Let me run the augmentation sweep, including the label-preserving mirror.
bash
cd /app && nohup python3 /app/exp_aug.py > /app/exp_aug.log 2>&1 &
echo "aug PID $!"; sleep 5; cat /app/exp_aug.log
output
aug PID 457
bash
cd /app && sleep 280 && cat /app/exp_aug.log
output
base           relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
Each config with 2 fold-seeds takes ~2.5 min. 5 configs = ~12 min. Let me wait more. base gives 0.2458.
bash
cd /app && sleep 290 && cat /app/exp_aug.log
output
base           relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
strong_drop    relL2=0.2530+-0.0035 mae=0.1547 maxabs=0.6851
with_aniso     relL2=0.2653+-0.0105 mae=0.1615 maxabs=0.7584
- base: 0.2458 (best so far) - strong_drop: 0.2530 (worse relL2, better maxabs) - with_aniso: 0.2653 (worse - anisotropic scaling hurts, as expected since it distorts the shape/bbox) Let me wait for with_rotz and with_mirrorx.
bash
cd /app && sleep 280 && cat /app/exp_aug.log
output
base           relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
strong_drop    relL2=0.2530+-0.0035 mae=0.1547 maxabs=0.6851
with_aniso     relL2=0.2653+-0.0105 mae=0.1615 maxabs=0.7584
with_rotz      relL2=0.2504+-0.0054 mae=0.1583 maxabs=0.6574
bash
cd /app && sleep 170 && cat /app/exp_aug.log && echo "running?" && ps aux | grep -c "[e]xp_aug"
output
base           relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
strong_drop    relL2=0.2530+-0.0035 mae=0.1547 maxabs=0.6851
with_aniso     relL2=0.2653+-0.0105 mae=0.1615 maxabs=0.7584
with_rotz      relL2=0.2504+-0.0054 mae=0.1583 maxabs=0.6574
with_mirrorx   relL2=0.2742+-0.0009 mae=0.1723 maxabs=0.8320
running?
0
Surprising: with_mirrorx is WORSE (0.2742). So mirroring along x hurts. This suggests the brackets are NOT symmetric about x=0, OR the reflected shapes are out-of-distribution enough to hurt. Actually, reflecting about x creates shapes that don't appear in the real data distribution (real brackets have a specific chirality/orientation), so it adds off-distribution examples that, while mass-preserving, shift the model's learned features away from the real distribution. So mirror hurts. Actually wait , my mirror implementation also adds dropout=0.2,resample=0.8 which is "strong_drop"-like. Let me compare with_mirrorx (0.2742) to strong_drop equivalent... with_mirrorx used dropout=0.2,resample=0.8 + mirror. The base of that (dropout 0.2, resample 0.8) alone isn't directly measured, but strong_drop (dropout 0.3, resample 0.8) was 0.2530. So mirror added on top pushed it to 0.2742 , mirror hurts. Conclusion: The simple 'base' aug (jitter=0.01, dropout=0.1, resample=0.5) remains best for relL2 at 0.2458. rot_z and strong_drop give better maxabs but worse relL2. So my best config is essentially: - epochs=300, bs=16, lr=1e-3, wd=1e-4, warmup=10, loss=mse, aug=base, swa_start=150, use_swa=True - relL2 ~0.242-0.246 Let me now think about whether there's any other lever. The model overfits (in-sample 0.05) but ensembling/aug don't close the gap much, and errors are systematic. Let me reconsider the SWA benefit and the schedule. Maybe a different LR schedule or longer training with more SWA collection helps. Also, maybe the issue is BN with tiny batches. Let me reconsider batch size: bs=16 on 110-132 samples gives 7-8 batches. BN stats are noisy. Larger batch (e.g., 32) gives more stable BN and gradients but fewer updates. Let me test bs and lr interactions, and also test a cyclic-LR SWA (collect multiple snapshots at LR peaks). Actually, let me step back and reconsider the whole approach given the plateau. The core difficulty: predict mass from scale-normalized surface point cloud, 132 training samples, fixed max-pool PointNet. relL2 ~0.24. Let me reconsider whether the input normalization could be improved. Currently global per-axis standardization. Since max-pool PointNet is sensitive to the coordinate scale, and the extents carry aspect-ratio info, maybe NOT standardizing per-axis (keeping physical proportions) is better or worse. The current feat_std ~[0.14,0.27,0.087] rescales axes to unit variance, which DISTORTS the aspect ratio that carries mass info! That might be bad. Let me test using an ISOTROPIC scale (single std for all axes) so aspect ratios are preserved, vs per-axis. This is a good insight: per-axis standardization destroys aspect-ratio information (it makes all axes unit variance, so a long-thin bracket and a cube look similar after normalization). Since mass correlates with how the shape fills space (aspect ratio matters), preserving relative axis scales might help. Let me test isotropic normalization (subtract per-axis mean, divide by a single scalar = mean of stds or max std). Let me test this. I'll add an option to trainer for isotropic feat normalization. Actually, the feat_mean/feat_std are computed inside train_one. Let me add a cfg flag 'iso_norm' that sets fs to a single scalar across axes. Let me also reconsider: the points are already in [-0.5,0.5] with max extent 1. Maybe NOT standardizing at all (feat_mean=0, feat_std=1, or feat_std= some constant) preserves everything. Let me test a few normalization schemes: 1. per-axis (current) 2. isotropic (per-axis mean, single std = mean of three stds) 3. center only, scale by global constant (e.g., 0.25) Let me test these. This is cheap and potentially impactful. Let me write the test.
Surprising but informative: mirror **hurts** (0.274) , the brackets have a consistent chirality, so reflections are off-distribution. The simple `base` aug remains best (0.246). Now a potentially important insight: the per-axis standardization (`feat_std` ≈ [0.14, 0.27, 0.09]) rescales each axis to unit variance, which **destroys the aspect-ratio information** that strongly correlates with mass. Let me test isotropic normalization (preserving proportions) against per-axis.
bash
cd /app && sed -n '120,135p' /app/trainer.py
output
for ep in range(epochs):
        for g in opt.param_groups: g['lr']=lr_at(ep)
        model.train()
        perm=torch.randperm(N,device=trX.device)
        for i in range(0,N,bs):
            idx=perm[i:i+bs]
            xb=trXn[idx]
            if cfg.get('aug'):
                xb=augment(xb,cfg['aug'])
            yb=trYn[idx]
            opt.zero_grad(set_to_none=True)
            pred=model(xb)
            loss=lossfn(pred,yb)
            loss.backward()
            if cfg.get('clip',0)>0:
                torch.nn.utils.clip_grad_norm_(model.parameters(),cfg['clip'])
str_replace_based_edit_tool
command: str_replace
path: /app/trainer.py
old_str:     fm = trX.mean(dim=(0,1),keepdim=True)
    fs = trX.std(dim=(0,1),keepdim=True).clamp_min(1e-6)
new_str:     fm = trX.mean(dim=(0,1),keepdim=True)
    fs = trX.std(dim=(0,1),keepdim=True).clamp_min(1e-6)
    nmode = cfg.get('norm','peraxis')
    if nmode=='iso':
        fs = fs.mean().expand_as(fs).contiguous()
    elif nmode=='isomax':
        fs = fs.max().expand_as(fs).contiguous()
    elif nmode=='const':
        fm = torch.zeros_like(fm)
        fs = torch.full_like(fs, float(cfg.get('norm_c',0.25)))
    elif nmode=='centeriso':
        fs = torch.full_like(fs, float(cfg.get('norm_c',0.25)))
output
The file /app/trainer.py has been edited successfully.
bash
cd /app && cat > /app/exp_norm.py << 'EOF'
from rcv import rep_oof
base=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,swa_start=150,use_swa=True,
          aug={'jitter':0.01,'dropout':0.1,'resample':0.5})
for nm in ['peraxis','iso','isomax','centeriso']:
    cfg={**base,'norm':nm}
    (rel,std),mae,mx=rep_oof(cfg, fold_seeds=(1234,99,7))
    print(f'norm={nm:10s} relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}',flush=True)
EOF
nohup python3 /app/exp_norm.py > /app/exp_norm.log 2>&1 &
echo "norm PID $!"
output
norm PID 528
This runs 4 norm modes * 3 fold-seeds * 6 folds * 300 epochs. ~ 4 * 180s = ~12 min. Let me wait and poll. Meanwhile, let me reason about what else to try. Let me also prepare the final training script so that once I pick the config, I can produce the checkpoint. The final model: - Train on all available labeled data. Question: 132 (train+val) or 148 (train+val+public_test)? - Use the best config + SWA. I'll decide on data after norm experiment. Let me also think: should I hold out public_test as a final sanity check, or include it? Given CV gives robust estimates and more data helps overfitting-limited models, including public_test (→148) is likely better for the final grade. But I'll first verify on public_test as a held-out check using a model trained on 132, to make sure my pipeline generalizes to a truly held-out split (public_test was never used in CABV tuning... well, I did glance at it early). Let me keep public_test as the final sanity check: train final on 132, check public_test, and ALSO produce a 148-trained version. I'll compare and decide. Actually, to maximize data for the final grade while retaining a sanity signal, I can do: train on 132, evaluate on public_test (held-out) to confirm the number is in the expected ~0.24 range, then retrain identically on 148 for the final checkpoint. The public_test check validates the procedure; the final uses all data. Let me wait for norm results.
While the normalization sweep runs, let me prepare the final-model builder so I can produce the checkpoint once the config is locked. Let me poll the norm sweep.
bash
cd /app && sleep 260 && cat /app/exp_norm.log
output
<system>Tool ran without output or errors</system>
bash
cd /app && sleep 120 && cat /app/exp_norm.log
output
norm=peraxis    relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
bash
cd /app && sleep 280 && cat /app/exp_norm.log
output
norm=peraxis    relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
norm=iso        relL2=0.2461+-0.0203 mae=0.1526 maxabs=0.7675
iso norm: 0.2461 ± 0.0203 (high variance). peraxis: 0.2421 ± 0.0054. So per-axis is still best and more stable. My hypothesis about aspect ratio was wrong , the network handles it fine either way, and per-axis normalization is better (probably because it gives balanced gradient scales across axes). Let me wait for isomax and centeriso.
bash
cd /app && sleep 290 && cat /app/exp_norm.log && ps aux | grep -c "[e]xp_norm"
output
norm=peraxis    relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
norm=iso        relL2=0.2461+-0.0203 mae=0.1526 maxabs=0.7675
norm=isomax     relL2=0.2397+-0.0150 mae=0.1488 maxabs=0.7506
1
isomax: 0.2397 ± 0.0150 , slightly better mean but higher variance. peraxis: 0.2421 ± 0.0054 , stable. These are within noise of each other. peraxis is the most stable. Let me wait for centeriso. So normalization doesn't matter much. I'll stick with peraxis (stable, and it's what the starter uses, robust). At this point, the model is plateaued around relL2 0.24. Let me consolidate: the best config is peraxis norm, wd=1e-4, base aug, SWA. Let me now think if there's any remaining structural improvement. Let me reconsider the SWA schedule and epochs more carefully, and also test whether a longer warmup / different lr helps. But gains are likely marginal. Actually, let me reconsider the problem from the data side. 132 training samples is very few. The single biggest lever might be: can I generate MORE training data? The mirror aug failed (off-distribution). But what about generating new samples by RESAMPLING the surface points differently , no, that's the same shape. What about interpolating between shapes (mixup)? Mixup on point clouds is tricky (can't average unordered points meaningfully). But I could do "mass mixup" , no. Alternatively, the mass is a physical quantity. Could I compute a better proxy feature and inject it? No, input is fixed to coords. I think I've reached a reasonable plateau. Let me now: 1. Confirm centeriso result. 2. Lock config: peraxis, wd=1e-4, base aug, epochs=300, swa_start=150, SWA, lr=1e-3, bs=16. 3. Do a final robustness check: verify on public_test with a model trained on 132, then train final on 148. Actually, before finalizing, let me reconsider the SWA details and test a couple more schedule variants quickly (more SWA, longer training) since those are cheap and could give the last bit. Also let me reconsider bs , maybe bs=8 (more updates) or bs=32 (stable BN). Let me do one more focused sweep on epochs/SWA/bs, then finalize. Let me wait for centeriso, then run a final schedule sweep. Actually, I realize I should be careful about total time budget. I have ~135k tokens left and each experiment is ~10-15 min of polling. Let me be efficient: one more combined sweep over a few schedule configs, then finalize. Let me wait for centeriso.
Normalization barely matters (peraxis is the most stable at 0.242). Let me get the last value, then run one focused schedule sweep (epochs/SWA/batch size) before locking the config.
bash
cd /app && sleep 130 && cat /app/exp_norm.log && echo "done?" && ps aux | grep -c "[e]xp_norm"
output
norm=peraxis    relL2=0.2421+-0.0054 mae=0.1514 maxabs=0.6993
norm=iso        relL2=0.2461+-0.0203 mae=0.1526 maxabs=0.7675
norm=isomax     relL2=0.2397+-0.0150 mae=0.1488 maxabs=0.7506
done?
1
bash
cd /app && sleep 90 && cat /app/exp_norm.log | tail -2 && ps aux | grep -c "[e]xp_norm"
output
norm=isomax     relL2=0.2397+-0.0150 mae=0.1488 maxabs=0.7506
norm=centeriso  relL2=0.2377+-0.0133 mae=0.1474 maxabs=0.7431
0
centeriso: 0.2377 ± 0.0133. Best mean, but higher variance than peraxis (0.2421 ± 0.0054). The differences are within noise. All normalization schemes are ~0.238-0.246. Given the noise, peraxis is safest (lowest variance, consistent). But centeriso/isomax have slightly better means. The variance in the estimates (0.013-0.020) is larger than the mean differences, so I can't reliably distinguish them. I'll go with peraxis for stability/robustness, since the grading set is a single draw and I want reliable behavior. Now let me run a final schedule sweep: test epochs (300 vs 500), swa collection (start point, and whether cyclic SWA helps), and bs. Let me combine into one background job with repeated CV (2 fold-seeds for speed). Let me be strategic about which configs: Config variants (all peraxis, wd=1e-4, base aug, lr=1e-3): 1. 'e300_swa150' (current best baseline) 2. 'e300_bs8' (more updates) 3. 'e300_bs32' (stable BN) 4. 'e500_swa250' (longer) 5. 'e400_cyclic' , cyclic LR SWA: after swa_start, use a cyclic LR to collect diverse snapshots. My current SWA averages every epoch after swa_start with cosine-decaying LR (LR is low near end). That collects low-LR snapshots (good for averaging). That's fine. Let me also test a higher LR (2e-3) and lower (5e-4). Actually, let me focus. The current config is solid. Let me test just: bs (8,16,32), epochs (300 vs 500), and lr (5e-4, 1e-3, 2e-3) , a small grid, in background. 2 fold-seeds each. Let me limit to the most impactful: bs and lr. Let me do a 3x2 grid = 6 configs * 2 foldseeds * 6 folds * ~300 epochs. That's ~ 6 * 120s = 12 min. OK. Actually let me combine lr and bs smartly. Let me do: - (lr=1e-3, bs=16) baseline - (lr=1e-3, bs=8) - (lr=1e-3, bs=32) - (lr=2e-3, bs=16) - (lr=5e-4, bs=16) - (lr=5e-4, bs=8) Let me run.
All normalization schemes land within noise (~0.238–0.246); `peraxis` has the lowest variance, so I'll keep it for robustness. Let me run one focused learning-rate/batch-size sweep to finalize the schedule.
bash
cd /app && cat > /app/exp_sched.py << 'EOF'
from rcv import rep_oof
base=dict(epochs=300,warmup=10,wd=1e-4,loss='mse',eval_every=1000,swa_start=150,use_swa=True,
          norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5})
grid=[
 ('lr1e3_bs16',dict(lr=1e-3,bs=16)),
 ('lr1e3_bs8', dict(lr=1e-3,bs=8)),
 ('lr1e3_bs32',dict(lr=1e-3,bs=32)),
 ('lr2e3_bs16',dict(lr=2e-3,bs=16)),
 ('lr5e4_bs16',dict(lr=5e-4,bs=16)),
 ('lr5e4_bs8', dict(lr=5e-4,bs=8)),
]
for name,ov in grid:
    cfg={**base,**ov}
    (rel,std),mae,mx=rep_oof(cfg, fold_seeds=(1234,99))
    print(f'{name:12s} relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}',flush=True)
EOF
nohup python3 /app/exp_sched.py > /app/exp_sched.log 2>&1 &
echo "sched PID $!"
output
sched PID 598
While this runs (~12 min), let me write the final model training script so it's ready. The final script will: 1. Load train+val (and optionally public_test) combined. 2. Train with the chosen config + SWA. 3. Save checkpoint in the required format (state_dict, feat_mean, feat_std, label_mean, label_std as the right shapes). Let me check the required shapes for the saved tensors: the starter squeezes them: feat_mean.squeeze() -> shape [3], feat_std -> [3], label_mean.squeeze() -> shape [1] (from [1,1]). Actually label_mean is computed as trY.mean(dim=0,keepdim=True) -> shape [1,1], squeeze -> scalar []? Let me be careful. The prompt says feat_mean/feat_std length-3 tensors, label_mean/label_std length-1 tensors. So feat_* shape [3], label_* shape [1]. My eval_ckpt loads and does .view(1,1,3) for feat and .view(1,1) for label, which requires feat to have 3 elements and label 1 element. Let me make the final saver produce shape [3] and [1] exactly. In train_one, fm has shape [1,1,3], fs [1,1,3], lm [1,1], ls [1,1]. For saving: feat_mean = fm.reshape(3), feat_std = fs.reshape(3), label_mean = lm.reshape(1), label_std = ls.reshape(1). Let me write the final trainer that returns the model and these stats and saves. I'll make it train on a specified data pool. Let me also make sure the grader's inference matches my assumption. The prompt: "feat_mean, feat_std - length-3 tensors used to standardize the input coordinates before the forward pass. The same normalization is applied at inference time." So inference does (x - feat_mean)/feat_std then forward. "label_mean, label_std ... model's output is mapped back to physical units using these." So physical = out*label_std + label_mean. My eval_ckpt.py already implements exactly this. Good , my CV/eval uses the same path, so my estimates are faithful. Let me write the final save function now.
While the schedule sweep runs, let me write the final checkpoint builder, matching the exact required output format (length-3 `feat_*`, length-1 `label_*`).
bash
cd /app && cat > /app/build_final.py << 'EOF'
import torch, json, sys
from trainer import load_split, train_one, predict, metrics, DEV

def build(out_path='/app/outputs/model.pt', pool=('train','val'), cfg=None, seed=0, check_test=True):
    parts=[load_split(s) for s in pool]
    X=torch.cat([p[0] for p in parts]).to(DEV)
    Y=torch.cat([p[1] for p in parts]).to(DEV)
    print(f'[final] training on {X.shape[0]} samples from {pool}', flush=True)
    r=train_one(X,Y,X,Y,cfg,seed=seed)  # pass X,Y as "val" just to populate stats; we don't select on it
    model=r['model']; fm=r['fm']; fs=r['fs']; lm=r['lm']; ls=r['ls']
    payload={
        'state_dict':{k:v.detach().cpu() for k,v in model.state_dict().items()},
        'feat_mean':fm.detach().reshape(3).cpu(),
        'feat_std':fs.detach().reshape(3).cpu(),
        'label_mean':lm.detach().reshape(1).cpu(),
        'label_std':ls.detach().reshape(1).cpu(),
    }
    import os; os.makedirs('/app/outputs',exist_ok=True)
    torch.save(payload, out_path)
    print(f'[final] wrote {out_path}', flush=True)
    # in-sample sanity
    p=predict(model,X,fm,fs,lm,ls)
    print('[final] in-sample:', tuple(round(v,4) for v in metrics(p,Y.ravel())), flush=True)
    return payload

if __name__=='__main__':
    cfg=dict(epochs=300,bs=16,lr=1e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
             norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5},
             swa_start=150,use_swa=True)
    build(cfg=cfg)
EOF
echo "build_final.py ready"
output
build_final.py ready
bash
cd /app && sleep 220 && cat /app/exp_sched.log
output
lr1e3_bs16   relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
bash
cd /app && sleep 280 && cat /app/exp_sched.log
output
lr1e3_bs16   relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
lr1e3_bs8    relL2=0.2659+-0.0166 mae=0.1593 maxabs=0.7438
bs=8 is worse (0.2659). Let me wait for the rest. bs=16 with lr=1e-3 is the baseline at 0.2458.
bash
cd /app && sleep 290 && cat /app/exp_sched.log
output
lr1e3_bs16   relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
lr1e3_bs8    relL2=0.2659+-0.0166 mae=0.1593 maxabs=0.7438
lr1e3_bs32   relL2=0.2480+-0.0082 mae=0.1577 maxabs=0.6349
lr2e3_bs16   relL2=0.2445+-0.0110 mae=0.1557 maxabs=0.6569
- lr1e3_bs16: 0.2458 ± 0.0010 (very stable), maxabs 0.7395 - lr1e3_bs32: 0.2480 ± 0.0082, maxabs 0.6349 (best maxabs!) - lr2e3_bs16: 0.2445 ± 0.0110, maxabs 0.6569 (best relL2 mean, good maxabs) lr2e3_bs16 has the best relL2 mean (0.2445) AND good maxabs (0.657). But higher variance. Let me wait for lr5e4 configs. Interesting that bs=32 and lr=2e-3 both improve maxabs substantially (0.64-0.66 vs 0.74). Since I care about all three metrics, lr=2e-3 bs=16 looks attractive: good relL2 and much better maxabs. Or bs=32 with lr maybe 2e-3. Let me see the last two, then maybe test lr=2e-3 with bs=32.
bash
cd /app && sleep 230 && cat /app/exp_sched.log && ps aux | grep -c "[e]xp_sched"
output
lr1e3_bs16   relL2=0.2458+-0.0010 mae=0.1527 maxabs=0.7395
lr1e3_bs8    relL2=0.2659+-0.0166 mae=0.1593 maxabs=0.7438
lr1e3_bs32   relL2=0.2480+-0.0082 mae=0.1577 maxabs=0.6349
lr2e3_bs16   relL2=0.2445+-0.0110 mae=0.1557 maxabs=0.6569
lr5e4_bs16   relL2=0.2483+-0.0032 mae=0.1555 maxabs=0.6680
1
- lr5e4_bs16: 0.2483 ± 0.0032, maxabs 0.668 Let me wait for the last (lr5e4_bs8). Then I'll consolidate. Summary so far (all ~0.244-0.266): - lr2e3_bs16: 0.2445, maxabs 0.657 , best relL2 - lr1e3_bs16: 0.2458, maxabs 0.740 , most stable relL2 but worst maxabs - lr1e3_bs32: 0.2480, maxabs 0.635 , best maxabs - lr5e4_bs16: 0.2483, maxabs 0.668 The differences in relL2 are within noise (~0.01). For the combined objective (relL2 primary, but also mae and maxabs), lr=2e-3 bs=16 or lr=1e-3 bs=32 look best because they improve maxabs a lot without hurting relL2. Let me test a couple more promising configs to pin the best for all three metrics: - lr2e3_bs32 - lr2e3_bs16 with slightly more wd (3e-4) for better maxabs - maybe a higher-LR cosine. Actually, I want to avoid over-tuning to CV noise. The estimates have std ~0.01, and I'm looking at differences of ~0.004. I should pick a robust config that does well on ALL three metrics and not chase the lowest relL2 point estimate. Given maxabs matters (worst-case), and lr=2e-3/bs16 and lr=1e-3/bs32 both give maxabs ~0.64-0.66 with relL2 ~0.245-0.248, these are good balanced choices. Let me do one more confirmatory repeated-CV (3 fold-seeds) on the top 2-3 candidates to reduce noise and pick the final. Candidates: A) lr2e3_bs16 B) lr1e3_bs32 C) lr2e3_bs32 (new) D) lr2e3_bs16 wd3e-4 (new) Let me run with 3 fold-seeds for stable comparison. That's 4 configs * 3 * 6 folds. ~ 4*180s = 12 min. Let me wait for the current last result first.
bash
cd /app && sleep 60 && cat /app/exp_sched.log | tail -1 && ps aux | grep -c "[e]xp_sched"
output
lr5e4_bs16   relL2=0.2483+-0.0032 mae=0.1555 maxabs=0.6680
1
bash
cd /app && sleep 60 && tail -1 /app/exp_sched.log && ps aux | grep -c "[e]xp_sched"
output
lr5e4_bs8    relL2=0.2559+-0.0118 mae=0.1596 maxabs=0.6646
0
Final sched results: - lr5e4_bs8: 0.2559 So the best balanced configs are lr2e3_bs16 (relL2 0.2445, maxabs 0.657) and lr1e3_bs32 (0.2480, maxabs 0.635). Let me run a confirmatory 3-fold-seed comparison on the top candidates plus a couple of new balanced ones to pick the final robustly. I want a config strong on all three metrics. Candidates for final confirmation (3 fold-seeds = 1234,99,7): A) lr2e3_bs16 wd1e-4 B) lr1e3_bs32 wd1e-4 C) lr2e3_bs32 wd1e-4 D) lr2e3_bs16 wd3e-4 E) lr1.5e3_bs24 wd2e-4 (middle ground) Let me run these.
Best balanced candidates: `lr2e3_bs16` (relL2 0.2445, maxabs 0.657) and `lr1e3_bs32` (0.2480, maxabs 0.635). Let me run a confirmatory 3-fold-seed comparison on the top candidates plus a couple of balanced variants to pick the final config robustly across all three metrics.
bash
cd /app && cat > /app/exp_final.py << 'EOF'
from rcv import rep_oof
base=dict(epochs=300,warmup=10,loss='mse',eval_every=1000,swa_start=150,use_swa=True,
          norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5})
grid=[
 ('A_lr2e3_bs16_wd1e4', dict(lr=2e-3,bs=16,wd=1e-4)),
 ('B_lr1e3_bs32_wd1e4', dict(lr=1e-3,bs=32,wd=1e-4)),
 ('C_lr2e3_bs32_wd1e4', dict(lr=2e-3,bs=32,wd=1e-4)),
 ('D_lr2e3_bs16_wd3e4', dict(lr=2e-3,bs=16,wd=3e-4)),
 ('E_lr15e4_bs24_wd2e4',dict(lr=1.5e-3,bs=24,wd=2e-4)),
]
for name,ov in grid:
    cfg={**base,**ov}
    (rel,std),mae,mx=rep_oof(cfg, fold_seeds=(1234,99,7))
    print(f'{name:20s} relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}',flush=True)
EOF
nohup python3 /app/exp_final.py > /app/exp_final.log 2>&1 &
echo "final-sweep PID $!"
output
final-sweep PID 675
This will take ~15 min (5 configs * 3 fold-seeds * 6 folds). Let me wait and poll. Meanwhile let me reason about the final data choice and do a clean held-out validation. Actually, I realize I should double check one thing: my rep_oof uses train_one with X[va],Y[va] passed as validation but with use_swa=True, the final model is SWA (doesn't use val for selection), and it recomputes BN on the TRAINING fold (X[tr] via the 'trX' passed). Wait, let me check recompute_bn call: in train_one, recompute_bn(model,trX,fm,fs,cfg) where trX is the training data passed (X[tr]). Good, BN recomputed on training fold, no leakage. And select_best is not set (use_swa takes precedence), so no val-based selection. Good , the OOF is clean (no leakage from val fold into model selection). Now, for the final model, build_final passes X,Y (full pool) as both train and "val", uses SWA → BN recomputed on full pool, no selection on val. Clean. Good. Let me wait for results. Let me poll in chunks.
The confirmatory sweep will take ~15 min. Let me verify my OOF has no leakage (SWA uses no val selection; BN is recomputed on the training fold only) while I wait.
bash
cd /app && sed -n '150,185p' /app/trainer.py
output
sd=model.state_dict()
                if swa_state is None:
                    swa_state={k:v.detach().clone().float() for k,v in sd.items()}
                    swa_n=1
                else:
                    swa_n+=1
                    for k,v in sd.items():
                        swa_state[k]+= (v.detach().float()-swa_state[k])/swa_n
        if vaX is not None and (ep%cfg.get('eval_every',10)==0 or ep==epochs-1):
            p=predict(model,vaX,fm,fs,lm,ls)
            rel,mae,mx=metrics(p,vaY)
            hist.append((ep,rel,mae,mx))
            if rel<best_val:
                best_val=rel; best_state={k:v.detach().clone() for k,v in model.state_dict().items()}
            if verbose: print(f'  ep{ep} val rel={rel:.4f} mae={mae:.4f} mx={mx:.4f}')
    result={'fm':fm,'fs':fs,'lm':lm,'ls':ls,'best_val':best_val,'hist':hist}
    # choose final state
    if cfg.get('use_swa') and swa_state is not None:
        model.load_state_dict({k:swa_state[k].to(v.dtype) for k,v in model.state_dict().items()})
        recompute_bn(model,trX,fm,fs,cfg)
        result['final']='swa'
    elif cfg.get('select_best') and best_state is not None:
        model.load_state_dict(best_state); result['final']='best'
    else:
        result['final']='last'
    result['model']=model
    if vaX is not None:
        p=predict(model,vaX,fm,fs,lm,ls)
        result['final_val']=metrics(p,vaY)
    return result
Good - the SWA branch doesn't use best_state (which is the only thing derived from val). With use_swa=True and eval_every=1000 (so eval only happens at ep 0 and last), the val fold is only used to COMPUTE metrics for reporting, never to select the model. BN is recomputed on trX (training fold). So the OOF is leakage-free. Let me wait for the final sweep. Let me poll periodically.
Confirmed leakage-free: with `use_swa=True` the model never uses the val fold for selection (BN recomputed on the training fold only). Let me poll the confirmatory sweep.
bash
cd /app && sleep 290 && cat /app/exp_final.log
output
A_lr2e3_bs16_wd1e4   relL2=0.2417+-0.0098 mae=0.1537 maxabs=0.6363
bash
cd /app && sleep 290 && cat /app/exp_final.log
output
A_lr2e3_bs16_wd1e4   relL2=0.2417+-0.0098 mae=0.1537 maxabs=0.6363
B_lr1e3_bs32_wd1e4   relL2=0.2456+-0.0074 mae=0.1542 maxabs=0.6771
C_lr2e3_bs32_wd1e4   relL2=0.2419+-0.0074 mae=0.1518 maxabs=0.6369
- A_lr2e3_bs16_wd1e4: relL2=0.2417, mae=0.1537, maxabs=0.6363 , good all around - B_lr1e3_bs32_wd1e4: relL2=0.2456, mae=0.1542, maxabs=0.6771 - C_lr2e3_bs32_wd1e4: relL2=0.2419, mae=0.1518, maxabs=0.6369 , best mae, good relL2 and maxabs A and C are very close and both strong on all three metrics. C has slightly better mae. Let me wait for D and E. The winner so far is lr=2e-3 (both A and C) which gives relL2 ~0.242, mae ~0.152, maxabs ~0.636. Notably better maxabs than the original lr=1e-3 bs=16 (0.74). So lr=2e-3 is a clear improvement for the combined objective. Let me wait for D and E.
`lr=2e-3` configs (A and C) are clearly best across all three metrics (relL2 ~0.242, maxabs ~0.636, much better than the original 0.74). Let me get the last two.
bash
cd /app && sleep 290 && cat /app/exp_final.log && ps aux | grep -c "[e]xp_final"
output
A_lr2e3_bs16_wd1e4   relL2=0.2417+-0.0098 mae=0.1537 maxabs=0.6363
B_lr1e3_bs32_wd1e4   relL2=0.2456+-0.0074 mae=0.1542 maxabs=0.6771
C_lr2e3_bs32_wd1e4   relL2=0.2419+-0.0074 mae=0.1518 maxabs=0.6369
D_lr2e3_bs16_wd3e4   relL2=0.2466+-0.0156 mae=0.1547 maxabs=0.6788
1
bash
cd /app && sleep 130 && tail -1 /app/exp_final.log && ps aux | grep -c "[e]xp_final"
output
D_lr2e3_bs16_wd3e4   relL2=0.2466+-0.0156 mae=0.1547 maxabs=0.6788
1
bash
cd /app && sleep 90 && tail -1 /app/exp_final.log && ps aux | grep -c "[e]xp_final"
output
E_lr15e4_bs24_wd2e4  relL2=0.2490+-0.0074 mae=0.1556 maxabs=0.7128
0
Final confirmatory sweep (3 fold-seeds each): - A_lr2e3_bs16_wd1e4: relL2=0.2417±0.0098, mae=0.1537, maxabs=0.6363 - B_lr1e3_bs32_wd1e4: relL2=0.2456±0.0074, mae=0.1542, maxabs=0.6771 - C_lr2e3_bs32_wd1e4: relL2=0.2419±0.0074, mae=0.1518, maxabs=0.6369 - D_lr2e3_bs16_wd3e4: relL2=0.2466±0.0156, mae=0.1547, maxabs=0.6788 - E_lr15e4_bs24_wd2e4: relL2=0.2490±0.0074, mae=0.1556, maxabs=0.7128 Winners: A and C are essentially tied and best on all three metrics. C (lr=2e-3, bs=32, wd=1e-4) has the best mae (0.1518), relL2 0.2419, and maxabs 0.6369, with lower variance than A (±0.0074 vs ±0.0098). I'll pick C as it's marginally more stable and has best mae while matching A on relL2/maxabs. Final config: - epochs=300, bs=32, lr=2e-3, wd=1e-4, warmup=10, loss=mse, norm=peraxis - aug: jitter=0.01, dropout=0.1, resample=0.5 - swa_start=150, use_swa=True Now, the decision about final training data: 132 (train+val) or 148 (train+val+public_test)? Let me do a clean held-out test: train on 132 with config C, evaluate on public_test (16 samples, truly held out since I only used it for a glance at the very start, never for tuning). This validates the procedure end-to-end through the actual checkpoint save/load path. Then I'll train the final on all 148 for maximum data. Actually, let me reconsider whether including public_test helps. More data generally helps an overfitting-limited model. public_test is 16 samples = +12% data. Worth including for the final grade. But I lose it as a check. Plan: 1. Train config C on 132, save to a temp path, evaluate via eval_ckpt.py on public_test. This is my honest held-out estimate + validates the save/load path. 2. Then train final config C on 148 (train+val+public_test), save to /app/outputs/model.pt. Let me also consider: should I run multiple seeds for the final model and pick... no, single model. SWA is built in. I'll use seed=0. But let me check seed sensitivity for the final , train a couple seeds on 132, check public_test, pick the more robust. Actually, since I can't select on the grading set, and seeds vary, I'll just use a fixed seed. But I could do a quick check that seed choice isn't wildly variable. Let me first do step 1: train on 132, eval on public_test. Let me run in background (it's a single training ~30-40s + recompute BN, quick). Let me just run it directly (should be under timeout). Let me build with config C on 132 and evaluate on public_test.
The confirmatory sweep is conclusive. Config **C** (`lr=2e-3, bs=32, wd=1e-4`) is best and most stable across all three metrics: relL2 0.2419±0.0074, mae 0.1518, maxabs 0.637. Now let me validate the full checkpoint save/load path: train config C on the 132 train+val samples and evaluate on the genuinely held-out `public_test` (which I never used for tuning).
bash
cd /app && timeout 200 python3 -c "
from build_final import build
cfg=dict(epochs=300,bs=32,lr=2e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
         norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5},
         swa_start=150,use_swa=True)
build(out_path='/app/outputs/model_132.pt', pool=('train','val'), cfg=cfg, seed=0)
" && echo "=== held-out eval on public_test ===" && python3 /app/eval_ckpt.py /app/outputs/model_132.pt
output
[final] training on 132 samples from ('train', 'val')
[final] wrote /app/outputs/model_132.pt
[final] in-sample: (0.097, 0.0636, 0.2626)
=== held-out eval on public_test ===
== /app/outputs/model_132.pt ==
  val          relL2=0.0858 mae=0.0572 maxabs=0.1905
  public_test  relL2=0.3162 mae=0.1933 maxabs=0.6683
The model trained on 132 (train+val) evaluates on public_test: relL2=0.3162, mae=0.1933, maxabs=0.6683. (val is in-sample now since we trained on it, so 0.0858 is meaningless.) public_test relL2 0.316 is higher than my CV estimate of 0.242. Hmm. That's concerning , public_test seems harder than the CV average. Recall public_test has 16 samples with label range 0.198-1.449 (mean 0.73, std 0.328) , it has a narrower range (no heavy 2.2 brackets) and smaller std. Wait, relL2 = ||err||/||true||. public_test has smaller ||true|| (narrower, lower masses) so the same absolute errors give a higher relL2. Also only 16 samples → noisy. The mae 0.193 is a bit higher than CV's 0.152. So public_test is genuinely a bit harder OR unlucky. This is a single draw of 16 samples, so high variance. My CV over 132 samples (0.242) is a more reliable estimate of general performance. The grading set is separate and presumably similar in size/distribution to these splits. The key question: does the grading distribution resemble public_test (harder, narrower) or the broader train/val? I don't know. Let me not over-index on public_test's 0.316. But let me reconsider: maybe I should train the final model on ALL 148 samples (including public_test) to maximize data AND ensure the model sees the public_test distribution. Since the grading set is held-out (different from all these), including public_test can only help by adding data. Let me build the final on 148. But wait , I want to estimate how the 148-trained model would do on the true held-out set. I have no held-out left if I use all 148. My best estimate remains the CV (0.242) which used 132. The 148 model should be at least as good (more data). Let me reconsider the public_test 0.316 result more carefully , is my model systematically off on public_test, or is it just the narrow-range effect? Let me look at public_test predictions in detail. Let me also run the CV but report per-fold to see variance. Actually, let me directly check: what's the relL2 if I evaluate the CASE where public_test is treated as one "fold" , i.e., train on all 132 and predict public_test. That's exactly what I did: 0.316. Let me compute what relL2 the simple mean-predictor gives on public_test (predict constant = train mean) as a reference scale, and the per-sample errors.
public_test relL2 (0.316) is higher than CV (0.242), but public_test has only 16 samples with a narrower, lower mass range (smaller ‖true‖ inflates relL2). Let me inspect the per-sample predictions and compare against trivial baselines to understand whether this is a real weakness or just the narrow-range/small-sample effect.
bash
cd /app && python3 -c "
import torch, numpy as np, json
from candidate_model import build_model
cfg=json.load(open('task_config.json'))
ck=torch.load('/app/outputs/model_132.pt',weights_only=True)
m=build_model(cfg); m.load_state_dict(ck['state_dict']); m.eval().cuda()
fm=ck['feat_mean'].view(1,1,3).cuda();fs=ck['feat_std'].view(1,1,3).cuda()
lm=ck['label_mean'].view(1,1).cuda();ls=ck['label_std'].view(1,1).cuda()
tr=torch.load('data/train/samples.pt',weights_only=True)
trmean=tr['labels'].float().mean().item()
d=torch.load('data/public_test/samples.pt',weights_only=True)
x=d['features'].float().cuda();y=d['labels'].float().cuda().ravel()
with torch.no_grad(): p=(m((x-fm)/fs)*ls+lm).ravel()
y=y.cpu().numpy();p=p.cpu().numpy()
err=p-y
print('pred vs true (sorted by true):')
for i in np.argsort(y):
    print(f'  true={y[i]:.3f} pred={p[i]:.3f} err={err[i]:+.3f}')
print()
rel=np.linalg.norm(err)/np.linalg.norm(y)
print(f'model relL2={rel:.4f} mae={np.abs(err).mean():.4f} maxabs={np.abs(err).max():.4f}')
# baseline: predict train mean
eb=trmean-y
print(f'mean-pred relL2={np.linalg.norm(eb)/np.linalg.norm(y):.4f} mae={np.abs(eb).mean():.4f}')
print('corr:', np.corrcoef(p,y)[0,1])
"
output
pred vs true (sorted by true):
  true=0.198 pred=0.415 err=+0.216
  true=0.286 pred=0.405 err=+0.119
  true=0.417 pred=0.485 err=+0.068
  true=0.520 pred=0.391 err=-0.128
  true=0.549 pred=0.530 err=-0.020
  true=0.566 pred=0.885 err=+0.318
  true=0.596 pred=1.265 err=+0.668
  true=0.633 pred=0.599 err=-0.034
  true=0.733 pred=0.574 err=-0.159
  true=0.793 pred=0.646 err=-0.147
  true=0.842 pred=1.080 err=+0.238
  true=0.938 pred=0.723 err=-0.215
  true=0.947 pred=0.821 err=-0.127
  true=1.083 pred=0.675 err=-0.408
  true=1.122 pred=0.902 err=-0.220
  true=1.449 pred=1.442 err=-0.007

model relL2=0.3162 mae=0.1933 maxabs=0.6683
mean-pred relL2=0.3995 mae=0.2607
corr: 0.6703902310219915
On public_test: - model relL2 0.316 vs mean-predictor 0.400. So the model adds value (correlation 0.67). - There's one big outlier: true=0.596, pred=1.265, err=+0.668. This single sample dominates maxabs (0.668) and inflates relL2 a lot. Without it, errors are mostly ≤0.4. This sample (true=0.596 but predicted 1.265) is a shape that looks "heavy" to the model but is actually light. Possibly a large but hollow/thin bracket. This is the kind of case where scale-normalization + max-pool fails: the shape occupies space like a heavy bracket but has less material. Given only 16 samples, one bad outlier inflates metrics. The CV estimate (0.242 over 132) is more reliable for the expected grade. Now, the question is whether including public_test in final training helps the held-out grade. It adds 16 more samples (including this "hard" type), which should help the model learn such cases. Let me go with training the final on all 148. But let me reconsider: there's a risk the grading distribution is like public_test (narrower/harder). To be safe and maximize generalization, training on all 148 (the union, covering the widest distribution including heavy 2.2 brackets from train and the public_test cases) is the best bet. Let me also reconsider whether a small ensemble-via-SWA-with-more-snapshots or a slightly different final could reduce the worst-case. But I've established ensembling hurts relL2. Let me also reconsider: should I use the broader data stats for normalization? When training on 148, feat_mean/std and label_mean/std computed on 148. Fine. Let me now also double-check robustness to seed for the final config by training 3 seeds on 132 and checking public_test spread , to make sure my single final model isn't a bad seed. Quick. Actually, that uses public_test for selection indirectly which I want to avoid. Instead, let me just confirm seed variance is small via the fact that CV std was ~0.0074. I'll train the final with a fixed seed. But to hedge against a bad seed, I could train several seeds and pick the one with best IN-SAMPLE fit? No, in-sample doesn't indicate generalization. Better hedge: Since ensembling predictions hurts relL2 (shrinkage), but I can only save one model anyway, I'll just use seed=0 which was used throughout and gave consistent CV. Hmm, but let me reconsider the SWA "shrinkage" finding in the context of a SINGLE model. SWA averages WEIGHTS (not predictions) along one trajectory , this is different from averaging predictions of independent models. Weight averaging in SWA generally improves generalization and does NOT cause the same prediction-shrinkage as ensembling independent models. My CV showed SWA (0.2468) slightly better than last-epoch (0.2507). So SWA is good. Keep it. Let me now build the FINAL model on all 148 samples with config C, seed 0, and save to /app/outputs/model.pt. Then validate it loads and produces correct shapes/outputs. Actually, let me reconsider one more time the data for final: train+val+public_test = 148. Let me verify build handles 3 pools. build() takes pool tuple and cats them. Good. Let me build the final. Wait , before that, let me reconsider whether there's any more juice. The plateau at ~0.24 CV seems robust. I've swept aug, norm, lr, bs, wd, SWA, ensembling, loss (implicitly mse best), log-space (worse). The model is data/representation limited. I'm confident config C is a good choice. One more idea for the worst-case/relL2: since the model under-predicts heavy brackets and over-predicts some light-but-bulky ones, and the problem is fundamental, I'll accept it. Let me also quickly test: does adding a tiny bit of the 'rot_z' help the final (earlier rot_z gave maxabs 0.657 and relL2 0.250 in the 2-foldseed aug test, but that was with stronger dropout). Not worth re-testing; base aug + lr2e3 already gives good maxabs (0.637). Let me build the final model on 148 samples. I'll run a few seeds and evaluate via CV-consistency... no. Let me just build seed 0, …[truncated]
The model beats the mean-predictor on public_test (relL2 0.316 vs 0.400, corr 0.67); the inflated number is driven mostly by one deceptive sample (a bulky-but-light bracket predicted heavy) in a 16-sample set. The 132-sample CV (0.242) remains my reliable estimate. Including public_test adds useful data (and exactly these hard cases), so I'll train the final model on all 148 samples with config C. Let me build it and verify the checkpoint format.
bash
cd /app && timeout 250 python3 -c "
from build_final import build
cfg=dict(epochs=300,bs=32,lr=2e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
         norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5},
         swa_start=150,use_swa=True)
build(out_path='/app/outputs/model.pt', pool=('train','val','public_test'), cfg=cfg, seed=0)
"
output
[final] training on 148 samples from ('train', 'val', 'public_test')
[final] wrote /app/outputs/model.pt
[final] in-sample: (0.0395, 0.0255, 0.1057)
Final model trained on 148 samples, saved to /app/outputs/model.pt. In-sample relL2 0.0395 (it fits training well, as expected). Now let me verify the checkpoint format rigorously: 1. Load it, check keys and shapes. 2. Verify it loads into PointNetRegressor via build_model. 3. Verify forward on [B,2048,3] produces [B,1]. 4. Verify the full inference path (normalize, forward, de-normalize) works. Let me write a strict validation that mimics what the grader likely does.
Final model saved. Now let me rigorously validate the checkpoint: correct keys, tensor shapes, clean load into the **unmodified** `PointNetRegressor`, and a correct `[B,2048,3] → [B,1]` forward through the full inference path.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model, PointNetRegressor
cfg=json.load(open('task_config.json'))
ck=torch.load('/app/outputs/model.pt', weights_only=True)
print('keys:', sorted(ck.keys()))
for k in ['feat_mean','feat_std','label_mean','label_std']:
    print(f'  {k}: shape={tuple(ck[k].shape)} dtype={ck[k].dtype} vals={ck[k].tolist()}')
# Build fresh model (as grader would) and load state_dict strictly
m=build_model(cfg)
missing,unexpected=m.load_state_dict(ck['state_dict'], strict=True)
print('strict load OK. missing=',missing,'unexpected=',unexpected)
assert isinstance(m, PointNetRegressor)
m.eval()
# Full inference path on a batch, exactly as described
fm=ck['feat_mean'].view(1,1,3); fs=ck['feat_std'].view(1,1,3)
lm=ck['label_mean'].view(1,1); ls=ck['label_std'].view(1,1)
x=torch.randn(5,2048,3)
with torch.no_grad():
    out=m((x-fm)/fs)*ls+lm
print('output shape:', tuple(out.shape), 'dtype', out.dtype)
assert out.shape==(5,1)
print('sample outputs (kg):', [round(v,3) for v in out.ravel().tolist()])
# check finite
assert torch.isfinite(out).all()
print('ALL FORMAT CHECKS PASSED')
"
output
keys: ['feat_mean', 'feat_std', 'label_mean', 'label_std', 'state_dict']
  feat_mean: shape=(3,) dtype=torch.float32 vals=[-0.011780548840761185, 0.007426036521792412, -0.07198601216077805]
  feat_std: shape=(3,) dtype=torch.float32 vals=[0.1422092616558075, 0.2692946195602417, 0.08725058287382126]
  label_mean: shape=(1,) dtype=torch.float32 vals=[0.7487966418266296]
  label_std: shape=(1,) dtype=torch.float32 vals=[0.38614240288734436]
strict load OK. missing= [] unexpected= []
output shape: (5, 1) dtype torch.float32
sample outputs (kg): [3.744, 0.485, 1.689, 3.143, 3.594]
ALL FORMAT CHECKS PASSED
All format checks pass: - Keys correct. - Shapes: feat_mean/std [3], label_mean/std [1]. ✓ - Strict load into fresh PointNetRegressor with no missing/unexpected keys. ✓ - Output [5,1], finite. ✓ The random-input outputs are large (3.7 kg) but that's because random Gaussian points don't resemble real brackets , irrelevant. Now, let me reconsider whether I should do a final robustness check on the actual saved model against real data. Since model.pt was trained on all 148 (including public_test), I can't evaluate held-out. But I can sanity-check it predicts reasonable values on the training pool (already did: in-sample 0.0395). Let me think about whether there's risk that the grader applies normalization differently. The prompt says feat_mean/feat_std standardize input coords "before the forward pass" and same at inference. My model was trained with exactly (x-fm)/fs. The saved fm/fs match training. Good. And label de-standardization: physical = out*ls+lm. Trained with (y-lm)/ls as target, so output*ls+lm recovers physical. Good. Now, one concern: BatchNorm running stats. At inference the grader will run model.eval() presumably (or not?). If the grader does NOT call model.eval(), BN would use batch statistics, which for a batch of test samples would differ from running stats → different predictions. But standard practice is eval mode for inference. The eval_ckpt.py I wrote uses eval(). My recompute_bn sets model.eval() at the end and the saved state_dict contains the running_mean/running_var. Let me verify the state_dict has BN running stats and num_batches_tracked, and that they're finite and reasonable. Also, I should consider: what if the grader runs the model in eval mode but feeds ALL test samples as one big batch, or one at a time? With eval mode + running stats, batch size doesn't matter. Good. Let me verify BN buffers are present and sane. Also there's a subtle issue: if the grader runs in train mode with a single sample, BN with batch size 1 would error or behave badly. But that's unlikely; eval mode is standard. I'll ensure running stats are well-estimated (my recompute_bn did 20 passes over 148 samples with bs=32). Let me verify BN buffers.
All format checks pass: correct keys, shapes ([3] and [1]), strict load into a fresh `PointNetRegressor`, and finite `[B,1]` output. Let me verify the BatchNorm running buffers are present and sane (inference uses eval-mode running stats), and confirm predictions are invariant to batch size and point ordering , properties a grader relies on.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
cfg=json.load(open('task_config.json'))
ck=torch.load('/app/outputs/model.pt', weights_only=True)
sd=ck['state_dict']
bn=[k for k in sd if 'running_mean' in k or 'running_var' in k or 'num_batches' in k]
print('BN buffers present:', len(bn))
for k in bn:
    t=sd[k].float()
    print(f'  {k}: finite={torch.isfinite(t).all().item()} min={t.min().item():.3f} max={t.max().item():.3f}')
# invariance checks
m=build_model(cfg); m.load_state_dict(sd); m.eval()
fm=ck['feat_mean'].view(1,1,3); fs=ck['feat_std'].view(1,1,3); lm=ck['label_mean'].view(1,1); ls=ck['label_std'].view(1,1)
d=torch.load('data/public_test/samples.pt',weights_only=True)
x=d['features'].float()
with torch.no_grad():
    # full batch
    pa=(m((x-fm)/fs)*ls+lm).ravel()
    # one-at-a-time
    pb=torch.cat([m(((x[i:i+1]-fm)/fs))*ls+lm for i in range(x.shape[0])]).ravel()
    # shuffled point order on first sample
    perm=torch.randperm(2048)
    p1=(m(((x[0:1]-fm)/fs)))*ls+lm
    p2=(m(((x[0:1,perm]-fm)/fs)))*ls+lm
print('max |batch - onebyone| =', (pa-pb).abs().max().item())
print('point-order invariance diff =', (p1-p2).abs().max().item())
"
output
BN buffers present: 15
  feature.net.1.running_mean: finite=True min=-0.609 max=0.567
  feature.net.1.running_var: finite=True min=0.008 max=1.021
  feature.net.1.num_batches_tracked: finite=True min=100.000 max=100.000
  feature.net.4.running_mean: finite=True min=-0.742 max=0.552
  feature.net.4.running_var: finite=True min=0.053 max=0.747
  feature.net.4.num_batches_tracked: finite=True min=100.000 max=100.000
  feature.net.7.running_mean: finite=True min=-0.412 max=0.493
  feature.net.7.running_var: finite=True min=0.049 max=0.325
  feature.net.7.num_batches_tracked: finite=True min=100.000 max=100.000
  lift.net.1.running_mean: finite=True min=-0.591 max=0.493
  lift.net.1.running_var: finite=True min=0.053 max=0.319
  lift.net.1.num_batches_tracked: finite=True min=100.000 max=100.000
  lift.net.4.running_mean: finite=True min=-1.024 max=0.533
  lift.net.4.running_var: finite=True min=0.062 max=0.645
  lift.net.4.num_batches_tracked: finite=True min=100.000 max=100.000
max |batch - onebyone| = 3.5762786865234375e-07
point-order invariance diff = 0.0
Everything checks out: - BN buffers present and sane (finite, reasonable ranges). - Batch-size invariance: max diff 3.6e-7 (numerical noise) → predictions identical whether batched or one-at-a-time. This confirms eval-mode BN works correctly regardless of how the grader batches. - Point-order invariance: exactly 0 (max-pool is permutation invariant). The model is robust to how the grader feeds data. Now let me reconsider whether I've truly maximized performance, or if there's a meaningfully better approach I'm missing. Let me reconsider the fundamental limitation once more. The CV estimate is ~0.24 relL2. This is the expected performance on held-out data drawn from the same distribution. I've been thorough: - Swept aug, norm, lr, bs, wd, loss, SWA, ensembling. - Found the model overfits but errors are systematic/correlated (ensembling doesn't help). - Log-space worse. - Calibration (affine) doesn't help. Is there anything architecturally I can exploit within the fixed model? The model is fixed, but the INPUT representation (via feat_mean/feat_std) is the only knob, and I tested normalization variants. Wait , one thing I haven't tried: the input is [B,2048,3]. The grader feeds the raw point cloud. But what if I could make the model more robust by training with the EXACT inference-time data (no aug) for the final BN recompute... I do recompute BN on clean training data (augment is only in the training loop, recompute_bn calls model with xb=(x-fm)/fs WITHOUT augmentation , let me verify). Let me check recompute_bn: it does `xb=(x-fm)/fs` then `model(xb[idx])` , no augmentation. Good, BN stats match clean inference distribution. Actually wait, there's a subtle point. During training, the model sees AUGMENTED inputs (jittered, dropout, resampled). During the final BN recompute, it sees CLEAN inputs. At inference, clean inputs. So BN recompute on clean is correct. Good. Let me reconsider the epochs and swa_start for the final. With 148 samples and bs=32, that's ~5 batches/epoch. 300 epochs = 1500 updates. swa_start=150 means SWA averages over epochs 150-299 (150 snapshots). That's fine. Let me reconsider if training longer would help the final model (more data now). Actually my CV used the same epochs and it was fine. Let me not change. Let me now think about variance reduction for the FINAL single model via a different mechanism: instead of one seed, I could train the final model, then fine-tune... no. Actually, let me reconsider the ensembling-hurts finding once more, because it's counterintuitive and important. When I averaged PREDICTIONS of multiple SWA models, relL2 got worse due to shrinkage on extremes. But what if I instead make the final model LESS shrunk? The shrinkage on heavy brackets is the main error source. Is there a training modification that reduces it? Options: 1. Importance weighting: weight heavy samples more in the loss. This directly fights the under-prediction of heavy brackets. But it could increase error on light brackets. For relL2 (which weights by absolute error), heavy brackets already dominate the loss via MSE (since their errors are largest). So MSE already "focuses" on them. Adding more weight might overfit to the few heavy samples. 2. Let me actually TEST importance weighting in CV: weight loss by the target value (or target²). This might reduce heavy-bracket under-prediction and improve relL2. Quick test worth doing. Let me test a weighted MSE where each sample's loss is weighted by (y/mean_y)^alpha for alpha in {0.5, 1.0}. This emphasizes heavy samples. I'll add a 'weighted' option to the loss. But the loss function in trainer takes (pred,yb) only. Let me add weighting support. Actually, for relL2 specifically, the OPTIMAL point prediction given the model's uncertainty is the conditional mean, and MSE targets that. Weighting changes what we target. But because the model is biased (systematic under-prediction of heavy due to limited capacity/data), weighting heavy samples more cou …[truncated]
Everything is robust: BN buffers are sane, predictions are invariant to batch size (diff ~3e-7) and point ordering (exactly 0). The checkpoint is valid and grader-safe. I have one more idea worth testing that directly targets the dominant error (under-prediction of heavy brackets): **sample-weighted loss** emphasizing heavier brackets. Let me add that option and CV-test it before deciding whether to rebuild.
str_replace_based_edit_tool
command: str_replace
path: /app/trainer.py
old_str:     lossfn=make_loss(cfg.get('loss','mse'))
    N=trX.shape[0]
    trXn=(trX-fm)/fs; trYn=(trY-lm)/ls
new_str:     lossfn=make_loss(cfg.get('loss','mse'))
    N=trX.shape[0]
    trXn=(trX-fm)/fs; trYn=(trY-lm)/ls
    walpha=cfg.get('wloss_alpha',0.0)
    if walpha>0:
        w_all=(trY/trY.mean()).clamp_min(1e-3)**walpha
        w_all=w_all/w_all.mean()
    else:
        w_all=None
output
The file /app/trainer.py has been edited successfully.
str_replace_based_edit_tool
command: str_replace
path: /app/trainer.py
old_str:             opt.zero_grad(set_to_none=True)
            pred=model(xb)
            loss=lossfn(pred,yb)
            loss.backward()
new_str:             opt.zero_grad(set_to_none=True)
            pred=model(xb)
            if w_all is not None:
                wb=w_all[idx]
                loss=((pred-yb)**2*wb).mean()
            else:
                loss=lossfn(pred,yb)
            loss.backward()
output
The file /app/trainer.py has been edited successfully.
bash
cd /app && cat > /app/exp_wloss.py << 'EOF'
from rcv import rep_oof
base=dict(epochs=300,bs=32,lr=2e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
          norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
for a in [0.0, 0.5, 1.0, 1.5]:
    cfg={**base,'wloss_alpha':a}
    (rel,std),mae,mx=rep_oof(cfg, fold_seeds=(1234,99,7))
    print(f'wloss_alpha={a}: relL2={rel:.4f}+-{std:.4f} mae={mae:.4f} maxabs={mx:.4f}',flush=True)
EOF
nohup python3 /app/exp_wloss.py > /app/exp_wloss.log 2>&1 &
echo "wloss PID $!"
output
wloss PID 839
This runs 4 alpha values * 3 fold-seeds * 6 folds. ~12 min. alpha=0.0 is the baseline (should reproduce ~0.242). Let me wait. While waiting, let me reconsider my overall approach and whether the final model is good. I've saved a valid model with CV ~0.24. The weighted loss test might improve it. Let me wait for results. Let me also double-check that my rep_oof reproduces config C baseline at alpha=0 to validate the weighting code didn't break anything. Let me poll.
The weighted-loss CV test is running (alpha=0 should reproduce the ~0.242 baseline, validating the new code path). Let me poll.
bash
cd /app && sleep 280 && cat /app/exp_wloss.log
output
wloss_alpha=0.0: relL2=0.2419+-0.0074 mae=0.1518 maxabs=0.6369
alpha=0.0 reproduces config C exactly (0.2419, mae 0.1518, maxabs 0.6369), confirming the weighting code path is correct (no change when alpha=0). Let me wait for the weighted variants.
alpha=0 exactly reproduces config C (0.2419), confirming the new code path is correct. Let me wait for the weighted variants.
bash
cd /app && sleep 290 && cat /app/exp_wloss.log
output
wloss_alpha=0.0: relL2=0.2419+-0.0074 mae=0.1518 maxabs=0.6369
wloss_alpha=0.5: relL2=0.2423+-0.0036 mae=0.1555 maxabs=0.6386
bash
cd /app && sleep 290 && cat /app/exp_wloss.log && ps aux | grep -c "[e]xp_wloss"
output
wloss_alpha=0.0: relL2=0.2419+-0.0074 mae=0.1518 maxabs=0.6369
wloss_alpha=0.5: relL2=0.2423+-0.0036 mae=0.1555 maxabs=0.6386
wloss_alpha=1.0: relL2=0.2396+-0.0029 mae=0.1516 maxabs=0.6774
1
- alpha=0.0: relL2=0.2419±0.0074, mae=0.1518, maxabs=0.6369 - alpha=0.5: relL2=0.2423±0.0036, mae=0.1555, maxabs=0.6386 - alpha=1.0: relL2=0.2396±0.0029, mae=0.1516, maxabs=0.6774 (best relL2, lowest variance, same mae, but worse maxabs) alpha=1.0 gives the best relL2 (0.2396) with much lower variance (±0.0029), same mae, but somewhat worse maxabs (0.677 vs 0.637). The primary metric is relL2, so alpha=1.0 is attractive. But maxabs worsens. Let me wait for alpha=1.5. Then decide. The relL2 improvement from weighting is small (0.2419→0.2396) and within noise, but the variance reduction is nice. The maxabs tradeoff is the concern. Since the prompt says "do not trade one off against the others," and alpha=1.0 improves relL2+mae but worsens maxabs, it's a genuine tradeoff. alpha=0 (config C) has the best maxabs and nearly-best relL2/mae. Let me see alpha=1.5. Actually, I realize the differences here are all within noise (std ~0.003-0.007, differences ~0.002). Weighting doesn't clearly help. The maxabs worsening at alpha=1.0 is a real signal though (emphasizing heavy samples makes the model over-predict some, increasing worst-case). Given the guidance to not trade off metrics, config C (alpha=0) remains the best balanced choice: relL2 0.2419, mae 0.1518, maxabs 0.6369 (best maxabs). My current saved model uses alpha=0. Good. Let me confirm alpha=1.5 then finalize with config C (already saved). Let me wait.
bash
cd /app && sleep 170 && cat /app/exp_wloss.log && ps aux | grep -c "[e]xp_wloss"
output
wloss_alpha=0.0: relL2=0.2419+-0.0074 mae=0.1518 maxabs=0.6369
wloss_alpha=0.5: relL2=0.2423+-0.0036 mae=0.1555 maxabs=0.6386
wloss_alpha=1.0: relL2=0.2396+-0.0029 mae=0.1516 maxabs=0.6774
wloss_alpha=1.5: relL2=0.2489+-0.0081 mae=0.1599 maxabs=0.6552
0
- alpha=1.5: relL2=0.2489 (worse), mae=0.1599 (worse), maxabs=0.6552 So alpha=1.0 is the sweet spot if I want lowest relL2, but it worsens maxabs. alpha=0 (config C) is the best balanced. The weighting doesn't give a clean win on all three metrics. Summary of weighting: - alpha=0: relL2 0.2419, mae 0.1518, maxabs 0.6369 , best maxabs, best mae (tied), 2nd relL2 - alpha=1.0: relL2 0.2396, mae 0.1516, maxabs 0.6774 , best relL2, best mae (tied), worst maxabs The relL2 difference (0.2419 vs 0.2396) is 0.0023, within the noise band. But maxabs difference (0.637 vs 0.677) is 0.04, more meaningful. Given the instruction to do well on ALL three and not trade off, config C (alpha=0) is the safer, better-balanced choice. I'll keep my current saved model (config C, alpha=0). Now let me reconsider: I've done extensive tuning. The final model is trained on all 148 samples with config C. My best held-out estimate is ~0.24 relL2 (from CV on 132). The public_test (included in training now) showed 0.316 but that's a small/hard sample. Let me reconsider whether training on 148 vs 132 is actually better for the grading set. The grading set is separate. Training on more data (148) should generalize at least as well. However, there's a subtle risk: if public_test is from a slightly different distribution, including it shifts the model. But it's more likely same distribution (just a split). I'll keep 148. Actually, let me reconsider this more carefully. Let me do a proper comparison: I can't evaluate the 148-model on held-out. But I can compare 132-model vs 148-model via CV-style reasoning: adding 16 random samples to the 132 pool should help. There's no reason it'd hurt. I'm confident 148 is fine. But hold on , let me reconsider whether I should hold out a bit to verify the FINAL artifact generalizes, versus using all data. The tension: more data = better model, but no final check. I've already validated the PROCEDURE via CV (0.24) and via the 132→public_test test (0.316, dominated by one outlier). The procedure is sound. Using all 148 for the final is the standard, correct choice to maximize the grade. Let me now make the final decision solid. I'll also reconsider: should I average a few SWA snapshots across multiple seeds via WEIGHT averaging? No , weight averaging across independent inits is invalid (permutation symmetry). SWA within one trajectory is what I use. Let me also reconsider whether to use alpha=1.0 for a tiny relL2 edge. The primary metric is relL2. alpha=1.0 gives 0.2396 vs 0.2419 , a 1% relative improvement in the primary metric, at the cost of 6% worse maxabs. The guidance explicitly says not to trade off. I'll stick with config C (balanced). Actually, let me reconsider by computing a combined view. Let me reconsider what "do well on all three" means for the grade. Likely the score aggregates all three. A balanced model is safer. Config C is balanced and has the best maxabs and mae, with relL2 essentially tied. Config C it is. Now, let me make sure my final saved model.pt is the config C trained on 148. I already saved it. But I ran the wloss experiment AFTER saving , that didn't touch model.pt (experiments use temp pools, don't write model.pt). Let me verify model.pt is intact and is the config C / 148 version. The in-sample was 0.0395 when I built it. Let me re-verify it's still there and valid, and hasn't been overwritten. Let me also do a final robustness thing: train config C on 148 with a couple different seeds and pick... no, I can't select on held-out. I'll keep seed 0. But let me at least confirm seed 0 isn't an outlier by checking that the saved model's behavior is reasonable. Actually, here's a thought: to reduce dependence on a single lucky/unlucky seed for the FINAL single model, I could train the final model and verify its in-sample and general behavior is consistent with CV. But in-sample doesn't tell generalization. Alternatively , and this is legitimate , I can use a LONGER SWA collection (more …[truncated]
The weighting results: alpha=1.0 gives a marginally better relL2 (0.2396 vs 0.2419, within noise) but a clearly worse max-abs (0.677 vs 0.637). Since the task explicitly says not to trade one metric for another, I'll keep the balanced **config C (alpha=0)**, which has the best max-abs and mae with essentially-tied relL2. Let me confirm the saved `model.pt` is intact (the experiments wrote only to temp paths) and reproduces its in-sample metrics.
bash
cd /app && ls -la outputs/ && echo "--- re-eval saved model.pt on the 148 training pool (sanity) ---" && python3 -c "
import torch, json
from candidate_model import build_model
from trainer import load_split, predict, metrics, DEV
cfg=json.load(open('task_config.json'))
ck=torch.load('/app/outputs/model.pt', weights_only=True)
m=build_model(cfg); m.load_state_dict(ck['state_dict']); m.eval().to(DEV)
fm=ck['feat_mean'].view(1,1,3).to(DEV);fs=ck['feat_std'].view(1,1,3).to(DEV)
lm=ck['label_mean'].view(1,1).to(DEV);ls=ck['label_std'].view(1,1).to(DEV)
import torch
parts=[load_split(s) for s in ('train','val','public_test')]
X=torch.cat([p[0] for p in parts]).to(DEV); Y=torch.cat([p[1] for p in parts]).to(DEV)
p=predict(m,X,fm,fs,lm,ls)
print('in-sample over 148:', tuple(round(v,4) for v in metrics(p,Y.ravel())))
print('pred range:', round(p.min().item(),3), round(p.max().item(),3), '| true range:', round(Y.min().item(),3), round(Y.max().item(),3))
"
output
total 763
drwxr-sr-x 2 h2tagent h2tagent   4096 Jun 20 23:03 .
drwxrws--- 1 h2tagent h2tagent   4096 Jun 20 23:05 ..
-rw-r--r-- 1 h2tagent h2tagent 384685 Jun 20 23:04 model.pt
-rw-r--r-- 1 h2tagent h2tagent 387121 Jun 20 23:03 model_132.pt
--- re-eval saved model.pt on the 148 training pool (sanity) ---
in-sample over 148: (0.0395, 0.0255, 0.1057)
pred range: 0.175 2.237 | true range: 0.198 2.219
The saved model.pt: - in-sample over 148: relL2 0.0395, mae 0.0255, maxabs 0.1057 , consistent with when I built it. - Prediction range [0.175, 2.237] matches true range [0.198, 2.219] well , the model spans the full mass range (not collapsed to the mean), which is good for the extremes. The model is healthy and is the correct config C / 148-sample artifact. Now let me reconsider one final potential improvement that I haven't fully explored: the seed sensitivity of the single final model. Since the grade depends on this one model, let me assess how much final performance varies by seed, using my held-out proxy (public_test with the 132-trained model across seeds). Even though public_test is now in the final training set, I can still use the 132-trained version across seeds to gauge seed-variance of the procedure. If variance is high, I might want a more robust final (e.g., pick a seed, or use SWA which I already do). Actually, a cleaner approach: I'll estimate seed variance via CV (already embedded , different folds use seed 0 only though). Let me instead just train config C on 132 for seeds {0,1,2,3} and eval each on public_test to see the spread. This tells me how much a single model's held-out metric varies by seed. It's a legitimate diagnostic (public_test was held out from the 132 training). Then for the final 148 model, I'll keep seed 0 (or pick the seed that's most central/robust, not the best on public_test to avoid overfitting to it). Let me run this seed-variance diagnostic. Hmm, but this uses public_test which is now in my final training set. For a DIAGNOSTIC of seed variance it's fine. Let me do it to understand variance, but NOT use it to pick the final seed (to avoid overfitting to public_test's 16 samples). I'll report and keep seed 0 unless seed 0 is a clear outlier. Actually, let me reconsider the time/token budget. I have ~106k tokens and have a solid, validated model. The seed diagnostic is informative but let me be efficient. Let me run it in background quickly (4 seeds, ~2 min total since each is one training). Let me do it. Wait, actually each full train on 132 + BN recompute is ~30-40s, 4 seeds = ~2.5 min. Let me run and poll once. Let me reconsider if there's a better use of remaining budget. I think confirming seed robustness is valuable since everything rides on one model. Let me do it.
The saved artifact is healthy: in-sample relL2 0.0395 and predictions span the full mass range [0.175, 2.237] ≈ true [0.198, 2.219], so it isn't collapsing toward the mean. Since the grade rides on this single model, let me quantify **seed sensitivity** of the procedure using the held-out public_test (via 132-trained models across seeds) , purely as a diagnostic, not for seed-picking.
bash
cd /app && cat > /app/exp_seed.py << 'EOF'
import torch
from trainer import load_split, train_one, predict, metrics, DEV
trX,trY=load_split('train'); vaX,vaY=load_split('val'); teX,teY=load_split('public_test')
X=torch.cat([trX,vaX]).to(DEV); Y=torch.cat([trY,vaY]).to(DEV)
teX=teX.to(DEV); teY=teY.to(DEV)
cfg=dict(epochs=300,bs=32,lr=2e-3,wd=1e-4,warmup=10,loss='mse',eval_every=1000,
         norm='peraxis', aug={'jitter':0.01,'dropout':0.1,'resample':0.5},swa_start=150,use_swa=True)
ps=[]
for s in range(5):
    r=train_one(X,Y,X,Y,cfg,seed=s)
    p=predict(r['model'],teX,r['fm'],r['fs'],r['lm'],r['ls'])
    ps.append(p)
    print(f'seed{s} public_test:', tuple(round(v,4) for v in metrics(p,teY.ravel())),flush=True)
pavg=torch.stack(ps).mean(0)
print('pred-avg public_test:', tuple(round(v,4) for v in metrics(pavg,teY.ravel())),flush=True)
EOF
nohup python3 /app/exp_seed.py > /app/exp_seed.log 2>&1 &
echo "seed PID $!"
output
seed PID 904
bash
cd /app && sleep 220 && cat /app/exp_seed.log && ps aux | grep -c "[e]xp_seed"
output
seed0 public_test: (0.3123, 0.1902, 0.6381)
seed1 public_test: (0.3072, 0.2002, 0.5823)
seed2 public_test: (0.3074, 0.1846, 0.6955)
seed3 public_test: (0.3495, 0.2223, 0.7012)
seed4 public_test: (0.3237, 0.1871, 0.7757)
pred-avg public_test: (0.3093, 0.1932, 0.6785)
0
Seed variance on public_test (132-trained): - seed0: relL2 0.3123, mae 0.1902, maxabs 0.6381 - seed1: 0.3072, 0.2002, 0.5823 - seed2: 0.3074, 0.1846, 0.6955 - seed3: 0.3495, 0.2223, 0.7012 - seed4: 0.3237, 0.1871, 0.7757 - pred-avg: 0.3093, 0.1932, 0.6785 So relL2 varies from 0.307 to 0.350 across seeds (mean ~0.32, std ~0.017). Seed 0 (0.3123) is near the better end , good. The prediction-average (0.3093) is about the same as the best single seeds; again ensembling doesn't help much here on relL2 (consistent with earlier finding). Importantly, seed 0 is a solid, slightly-better-than-average seed on this held-out proxy. So my choice of seed 0 for the final model is reasonable (not an unlucky outlier). The public_test relL2 (~0.31) is consistently higher than CV (~0.24) across all seeds. This confirms public_test is genuinely a bit harder/narrower (not a fluke of one seed). This is the narrow-range effect I noted: public_test masses are lower/narrower (max 1.449 vs train max 2.219), so ‖true‖ is smaller and relL2 is inflated for similar absolute errors. The mae (~0.19) is more stable and comparable across splits. So my realistic expectation for the grading set: relL2 somewhere in 0.24-0.32 depending on how its mass distribution compares to train (broad) vs public_test (narrow). mae ~0.15-0.19. maxabs ~0.6-0.7. My final model (config C, seed 0, 148 samples) is a good, well-validated choice. Training on 148 (including public_test) should help it handle the public_test-like distribution better than the 132-model did. Now, let me reconsider: since seed 0 on 132 gave public_test relL2 0.3123 and was near-best, and the final uses 148 (+public_test data), the final should be at least as good. I'm confident in the final artifact. Let me reconsider whether I should instead use the prediction-average seed approach , but I can only save ONE model. Pred-averaging requires multiple models. Not allowed. SWA (weight avg along trajectory) is my single-model smoothing, already applied. Let me reconsider one subtle point about training on 148 including public_test: by including public_test in training, the final model won't have the public_test "hard outlier" (true=0.596, pred=1.265) as an error anymore , it'll fit it. This genuinely helps if the grading set contains similar shapes. Good. I think the model is well-optimized given the constraints. Let me reconsider if there's any remaining lever I'm missing: 1. ✅ Architecture: fixed, can't change. 2. ✅ Normalization (feat): tested peraxis/iso/isomax/centeriso , peraxis stable best. 3. ✅ Label transform: linear best (log worse), affine calibration doesn't help. 4. ✅ Augmentation: jitter+dropout+resample best; mirror/aniso/rot hurt or neutral. 5. ✅ LR/bs/wd: lr=2e-3, bs=32, wd=1e-4 best balanced. 6. ✅ SWA: helps slightly, used. 7. ✅ Ensembling: hurts relL2 (shrinkage), not used. 8. ✅ Weighted loss: marginal relL2 gain but worse maxabs, not used (keep balanced). 9. ✅ Epochs=300, warmup=10: fine. 10. ✅ Data: use all 148 for final. I've been thorough. The model is as good as I can reasonably get within the fixed architecture and tiny dataset. Let me do final housekeeping: - Remove the temp model_132.pt (keep only model.pt)? The task only requires model.pt. Extra files are harmless but let me clean up to be tidy. Actually, leaving model_132.pt is harmless. But to avoid any confusion, let me remove it. - Verify model.pt one final time with a fresh process and the exact inference contract. Actually, let me reconsider whether to rebuild the final with a fresh, clean seed-0 run to be 100% sure the saved model.pt corresponds exactly to config C (it does , I built it with config C). The in-sample reproduced (0.0395). It's correct. Let me reconsider: is there any benefit to choosing the final model by training a few seeds on ALL 148 and picking the one whose predictions best match... no held-out. I'll keep seed 0 which I've validated is a good seed. Let me reconsider robustness once more: the …[truncated]
Seed variance is modest (relL2 0.307–0.350 across 5 seeds) and **seed 0 is near the best** (0.3123), so it's a safe choice for the final model , not an unlucky outlier. Prediction-averaging again doesn't beat the best single seed, reaffirming that a single SWA model is the right call. The consistent public_test≈0.31 vs CV≈0.24 gap is the narrow-mass-range effect (smaller ‖true‖), not a seed fluke. Let me clean up the temp checkpoint and run a final, strict grader-style validation in a fresh process , including a float16 input (since data is stored as float16, the grader may pass either dtype).
bash
cd /app && rm -f outputs/model_132.pt && python3 -c "
import torch, json
from candidate_model import build_model
# --- simulate grader exactly, fresh process ---
cfg=json.load(open('/app/task_config.json'))
ck=torch.load('/app/outputs/model.pt', weights_only=True)
req={'state_dict','feat_mean','feat_std','label_mean','label_std'}
assert req.issubset(ck.keys()), ck.keys()
model=build_model(cfg)
model.load_state_dict(ck['state_dict'], strict=True)
model.eval()
fm=ck['feat_mean'].view(1,1,3); fs=ck['feat_std'].view(1,1,3)
lm=ck['label_mean'].view(1,1); ls=ck['label_std'].view(1,1)

def infer(x):
    x=x.float()
    with torch.no_grad():
        return (model((x-fm)/fs)*ls+lm)

d=torch.load('/app/data/public_test/samples.pt', weights_only=True)
# float16 path (as stored on disk)
x16=d['features']  # float16
y=d['labels'].float().ravel()
out16=infer(x16)
# float32 path
out32=infer(d['features'].float())
print('float16 vs float32 output max diff:', (out16-out32).abs().max().item())
print('output shape', tuple(out16.shape), 'finite', bool(torch.isfinite(out16).all()))
err=(out16.ravel()-y)
rel=(torch.linalg.norm(err)/torch.linalg.norm(y)).item()
print(f'public_test (final 148-model): relL2={rel:.4f} mae={err.abs().mean():.4f} maxabs={err.abs().max():.4f}')
print('NOTE: public_test was included in final training, so this is partly in-sample.')
print('CONTRACT OK')
" && echo "--- outputs dir ---" && ls -la outputs/
output
float16 vs float32 output max diff: 0.0
output shape (16, 1) finite True
public_test (final 148-model): relL2=0.0302 mae=0.0188 maxabs=0.0671
NOTE: public_test was included in final training, so this is partly in-sample.
CONTRACT OK
--- outputs dir ---
total 384
drwxr-sr-x 2 h2tagent h2tagent   4096 Jun 20 23:27 .
drwxrws--- 1 h2tagent h2tagent   4096 Jun 20 23:23 ..
-rw-r--r-- 1 h2tagent h2tagent 384685 Jun 20 23:04 model.pt
Final validation passes: - Required keys present. - Strict state_dict load. - float16 and float32 inputs give IDENTICAL outputs (max diff 0.0) , robust to input dtype. - Output shape [16,1], finite. - public_test now fits well (0.0302) since it's in-sample , confirms the final model learned those cases. - Only model.pt in outputs/. The contract is satisfied and the model is robust. Let me reflect on whether I'm confident this is the best deliverable: My honest generalization estimate (from leakage-free CV on 132 samples): relL2 ≈ 0.242, mae ≈ 0.152, maxabs ≈ 0.637. The final model trained on 148 should be comparable or slightly better due to more data. I've thoroughly explored the space and the model is at a robust optimum for the fixed architecture. Let me now think very carefully if there's anything that could go wrong at grading: 1. What if the grader does NOT apply the feat normalization and instead passes raw coords? The prompt explicitly says "The same normalization is applied at inference time, so these are required." So it applies. Good. 2. What if the grader uses a different de-standardization? Prompt says output mapped back using label_mean/label_std. Standard: out*std+mean. That's what I assume. This is the universal convention and matches the starter's norm_y inverse. Good. 3. What if the grader keeps model in train() mode? Then BN uses batch stats. Let me test this edge case , if train mode with the full public_test batch gives very different results, that's a risk. Let me check. Actually, a well-behaved grader uses eval(). But let me test train-mode behavior to understand the risk. If it's catastrophic, I might consider reducing BN's reliance... but I can't change architecture. Actually, the running stats are well-estimated, and if grader uses eval() (standard), it's fine. Let me just verify train-mode isn't catastrophically different as a robustness note, but I won't over-engineer. Let me quickly check train-mode vs eval-mode difference on public_test (as a batch of 16). Actually, this is an important robustness check. Many inference harnesses do call .eval(), but let me see the magnitude of risk.
Final validation passes cleanly: required keys present, strict load, **float16 and float32 inputs produce identical outputs** (diff 0.0), `[16,1]` finite output, and only `model.pt` remains in outputs. The near-zero public_test error just confirms those samples are now in-sample. As a last robustness probe, let me check the eval-vs-train-mode BatchNorm sensitivity , a well-behaved grader calls `.eval()`, but I want to understand the downside if it doesn't.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
from trainer import load_split, metrics, DEV
cfg=json.load(open('/app/task_config.json'))
ck=torch.load('/app/outputs/model.pt', weights_only=True)
m=build_model(cfg); m.load_state_dict(ck['state_dict']); m.to(DEV)
fm=ck['feat_mean'].view(1,1,3).to(DEV);fs=ck['feat_std'].view(1,1,3).to(DEV)
lm=ck['label_mean'].view(1,1).to(DEV);ls=ck['label_std'].view(1,1).to(DEV)
vaX,vaY=load_split('val'); vaX=vaX.to(DEV); vaY=vaY.to(DEV).ravel()
xb=(vaX-fm)/fs
m.eval()
with torch.no_grad(): pe=(m(xb)*ls+lm).ravel()
m.train()
with torch.no_grad(): pt=(m(xb)*ls+lm).ravel()  # batch of 32
print('eval-mode  val (in-sample):', tuple(round(v,4) for v in metrics(pe,vaY)))
print('train-mode val (batch=32) :', tuple(round(v,4) for v in metrics(pt,vaY)))
print('max |eval-train| pred diff:', (pe-pt).abs().max().item())
"
output
eval-mode  val (in-sample): (0.0407, 0.0256, 0.0896)
train-mode val (batch=32) : (0.0486, 0.0332, 0.115)
max |eval-train| pred diff: 0.07344710826873779
Train-mode vs eval-mode difference is modest (max pred diff 0.073, and metrics only slightly worse in train mode: 0.0407→0.0486 relL2 in-sample). So even in the unlikely case the grader forgets .eval(), the degradation is small and not catastrophic. This is because BN running stats are close to the batch stats for reasonably-sized batches. Good , the model is robust to this edge case. I'm confident in the deliverable. Let me write a concise summary of the final approach and results. Let me also make sure the helper files I created don't interfere with anything (they're just in /app, and the only required output is /app/outputs/model.pt). Let me do a final listing and a clean summary. Let me also verify once more that model.pt loads with weights_only=True (the method specified in the prompt for loading data files, and likely for the checkpoint too). Actually, I already verified weights_only=True loading works throughout. Let me reconsider whether I should also provide a reproducible training script as a nicety. The task says "train.py - a small starter training loop you can extend or replace." I could overwrite train.py with my final training recipe so the process is reproducible. That's good practice and aligns with "extend or replace." Let me update train.py to reflect my final approach, so that running it reproduces model.pt. This also documents my method clearly. Let me write a clean final train.py that uses my trainer components but is self-contained enough. Actually, train.py importing from trainer.py is fine since both are in /app. But to be safe and self-contained (in case the grader runs train.py fresh), let me make train.py reproduce the final model using the modules I've built. It should train config C on train+val+public_test with SWA and save to outputs/model.pt. Let me rewrite train.py to be the canonical reproduction script. Let me make train.py self-contained by importing from trainer.py and build_final.py (which are present). Or I can make it call build_final.build. Let me write a clean version. Actually, the cleanest: train.py that defines the final cfg and calls build_final.build. Let me do that, keeping it readable and faithful. Let me write it.
Train-mode vs eval-mode differs only modestly (max pred diff 0.073), so the model degrades gracefully even if a harness forgets `.eval()`. The deliverable is robust. Finally, let me replace the starter `train.py` with a clean, self-contained script that reproduces my final model, so the method is documented and repeatable.
str_replace_based_edit_tool
command: create
path: /app/train.py
file_text: from __future__ import annotations

"""Reproduce the final jet-engine-bracket mass model.

Summary of the approach (chosen via leakage-free k-fold CV on train+val):
  * Fixed PointNet architecture from candidate_model.py (unchanged).
  * Inputs standardized per-axis with train statistics; targets standardized
    to zero mean / unit std. Both transforms are saved in the checkpoint so the
    exact same normalization is applied at inference.
  * Light, label-preserving augmentation: point resampling, point dropout and
    small coordinate jitter. (Mirror / anisotropic-scale / rotation aug were
    tested and hurt, so they are not used.)
  * AdamW, lr=2e-3, batch_size=32, weight_decay=1e-4, cosine schedule with
    warmup, MSE loss on standardized targets.
  * Stochastic Weight Averaging over the second half of training, followed by a
    BatchNorm statistics recomputation on clean (un-augmented) data.
  * The final model is trained on all available labeled data
    (train + val + public_test) to make the most of a very small dataset.

CV estimate of held-out performance: relL2 ~= 0.24, MAE ~= 0.15.
"""

import os
import sys
from pathlib import Path

APP_DIR = Path(os.environ.get("APP_DIR", "/app"))
sys.path.insert(0, str(APP_DIR))

from build_final import build  # noqa: E402

FINAL_CFG = dict(
    epochs=300,
    bs=32,
    lr=2e-3,
    wd=1e-4,
    warmup=10,
    loss="mse",
    norm="peraxis",
    aug={"jitter": 0.01, "dropout": 0.1, "resample": 0.5},
    swa_start=150,
    use_swa=True,
    eval_every=1000,
)


def main() -> None:
    out_path = str(APP_DIR / "outputs" / "model.pt")
    build(
        out_path=out_path,
        pool=("train", "val", "public_test"),
        cfg=FINAL_CFG,
        seed=0,
    )


if __name__ == "__main__":
    main()
output
Existing file was successfully overwritten at /app/train.py
Let me verify that running the new train.py reproduces the model end-to-end (fresh run), and that it writes a valid model.pt. This confirms reproducibility. I'll run it and then re-validate the format once more. This is the final confirmation. Let me run train.py.
Let me confirm the rewritten `train.py` reproduces a valid checkpoint end-to-end from a clean run.
bash
cd /app && timeout 250 python3 train.py && echo "=== re-validate artifact ===" && python3 -c "
import torch, json
from candidate_model import build_model
cfg=json.load(open('/app/task_config.json'))
ck=torch.load('/app/outputs/model.pt', weights_only=True)
assert {'state_dict','feat_mean','feat_std','label_mean','label_std'}<=set(ck)
m=build_model(cfg); m.load_state_dict(ck['state_dict'], strict=True); m.eval()
for k,shp in [('feat_mean',(3,)),('feat_std',(3,)),('label_mean',(1,)),('label_std',(1,))]:
    assert tuple(ck[k].shape)==shp, (k, ck[k].shape)
x=torch.randn(3,2048,3)
o=(m((x-ck['feat_mean'].view(1,1,3))/ck['feat_std'].view(1,1,3))*ck['label_std'].view(1,1)+ck['label_mean'].view(1,1))
assert o.shape==(3,1) and torch.isfinite(o).all()
print('reproduced model.pt is valid; output shape', tuple(o.shape))
"
output
[final] training on 148 samples from ('train', 'val', 'public_test')
[final] wrote /app/outputs/model.pt
[final] in-sample: (0.0395, 0.0255, 0.1057)
=== re-validate artifact ===
reproduced model.pt is valid; output shape (3, 1)
The rewritten train.py reproduces the model deterministically (in-sample 0.0395 matches exactly, confirming seed determinism). The artifact is valid. Final state: - /app/outputs/model.pt: the final deliverable, valid format. - train.py: reproduces it. - Supporting modules: trainer.py, build_final.py, dataset.py, candidate_model.py (unchanged). Let me do a final directory check to make sure everything is in order and candidate_model.py is unchanged (I never edited it). Let me verify candidate_model.py is unmodified (diff against what I'd expect , I never touched it, but let me confirm the key constraint that my state_dict loads into the original architecture, which I've already verified with strict=True). I'm confident. Let me give a final summary of the work. Let me make one final listing of /app/outputs and confirm candidate_model.py untouched.
The rewritten `train.py` reproduces the model deterministically (in-sample 0.0395 matches exactly). Let me do a final check of the outputs directory and confirm the fixed architecture file was never modified.
bash
cd /app && echo "=== outputs/ ===" && ls -la outputs/ && echo "=== candidate_model.py unchanged? (git/time check) ===" && ls -la candidate_model.py && echo "=== final checkpoint summary ===" && python3 -c "
import torch
ck=torch.load('/app/outputs/model.pt', weights_only=True)
print('keys:', sorted(ck))
for k in ['feat_mean','feat_std','label_mean','label_std']:
    print(f'  {k}: {ck[k].tolist()}')
print('state_dict tensors:', len(ck['state_dict']))
print('total params:', sum(v.numel() for v in ck['state_dict'].values()))
"
output
=== outputs/ ===
total 384
drwxr-sr-x 2 h2tagent h2tagent   4096 Jun 20 23:27 .
drwxrws--- 1 h2tagent h2tagent   4096 Jun 20 23:28 ..
-rw-r--r-- 1 h2tagent h2tagent 384685 Jun 20 23:28 model.pt
=== candidate_model.py unchanged? (git/time check) ===
-rw-rw---- 1 h2tagent h2tagent 1639 Jun 20 18:10 candidate_model.py
=== final checkpoint summary ===
keys: ['feat_mean', 'feat_std', 'label_mean', 'label_std', 'state_dict']
  feat_mean: [-0.011780548840761185, 0.007426036521792412, -0.07198601216077805]
  feat_std: [0.1422092616558075, 0.2692946195602417, 0.08725058287382126]
  label_mean: [0.7487966418266296]
  label_std: [0.38614240288734436]
state_dict tensors: 41
total params: 93446
The deliverable is complete and validated. Here's a summary of what I did and why. ## Outcome `/app/outputs/model.pt` contains a trained checkpoint with all five required keys in the exact expected shapes (`feat_mean`/`feat_std` length‑3, `label_mean`/`label_std` length‑1, plus `state_dict`). It loads **strictly** into the unmodified `PointNetRegressor`, consumes `[B, 2048, 3]`, and returns `[B, 1]`. `candidate_model.py` was left untouched. ## Key findings from exploration - **Scale is removed**: every bracket is individually scaled so its longest axis = 1.0, so mass must be inferred from shape/proportions (learnable because SimJEB brackets share a design envelope). - **Tiny data** (100/32/16 split, no bracket overlap). The model fits train to relL2≈0.05 but generalizes to ≈0.24 , a **variance/overfitting** regime, so I focused on regularization, augmentation, and data. - **Errors are systematic, not noise**: averaging independent seeds *worsened* relL2 (extra shrinkage on the heavy brackets that dominate relL2), so ensembling/distillation wouldn't help , a single well-regularized model is the right call. - Log-target and affine calibration didn't help (bias is conditional, not global); mirror/anisotropic/rotation augmentations hurt (brackets have consistent chirality/orientation). ## Final recipe (selected via leakage-free repeated k-fold CV on train+val) PointNet + per-axis input standardization, light label-preserving aug (resample/dropout/jitter), AdamW `lr=2e-3, bs=32, wd=1e-4`, cosine schedule with warmup, MSE on standardized targets, **SWA** over the second half of training with a clean BatchNorm recompute. The final model trains on **all 148 labeled samples**. CV estimate of held-out performance: **relL2 ≈ 0.24, MAE ≈ 0.15, max-abs ≈ 0.64** , chosen as the best-*balanced* config across all three metrics (I deliberately rejected a weighted-loss variant that shaved relL2 but worsened worst-case error). ## Robustness verified Identical outputs for float16 vs float32 inputs, invariance to batch size (~3e-7) and point ordering (exactly 0), sane BN buffers, and graceful behavior even if `.eval()` were omitted. I also rewrote `train.py` to reproduce the checkpoint deterministically. One caveat worth flagging: my strongest honest generalization estimate is the train+val CV (~0.24 relL2); the 16-sample public_test looked harder (~0.31 across seeds), but that is almost entirely the narrow/low mass range inflating relL2 (smaller ‖true‖) on a tiny sample rather than a model defect , MAE was stable (~0.19) and the model clearly beat the mean-predictor there (0.32 vs 0.40).
Final diff , what the agent changed

No file changes, the agent left the workspace untouched.

Verifier output , the proof behind the reward
tests/test.sh
# SyncVals normalized verifier summary
# task: simjeb-bracket-fea-mass-prediction-real
# attempt: 4  status: completed  raw_score: 0.41
# reward rule: continuous: score 0.41 < 0.5
# => reward = 0.0  (FAIL)
#
# Note: these tasks score via an external hidden grader; no pytest/verifier
# block is embedded in the agent transcript. The block below is the last
# sizable tool-output captured in the run (supporting evidence).
----------------------------------------------------------------------
=== outputs/ ===
total 384
drwxr-sr-x 2 h2tagent h2tagent   4096 Jun 20 23:27 .
drwxrws--- 1 h2tagent h2tagent   4096 Jun 20 23:28 ..
-rw-r--r-- 1 h2tagent h2tagent 384685 Jun 20 23:28 model.pt
=== candidate_model.py unchanged? (git/time check) ===
-rw-rw---- 1 h2tagent h2tagent 1639 Jun 20 18:10 candidate_model.py
=== final checkpoint summary ===
keys: ['feat_mean', 'feat_std', 'label_mean', 'label_std', 'state_dict']
  feat_mean: [-0.011780548840761185, 0.007426036521792412, -0.07198601216077805]
  feat_std: [0.1422092616558075, 0.2692946195602417, 0.08725058287382126]
  label_mean: [0.7487966418266296]
  label_std: [0.38614240288734436]
state_dict tensors: 41
total params: 93446

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_ce92dc6240d94754. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_ce92dc6240d94754 · verifier authoritative; classifier explanatory.