SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

ks-equation-1d-forecast

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.
SubtypePoor Generalization to Hidden Test Set
EvidenceAgent achieved local validation rollout_rel_l2_score ≈ 0.0015-0.0016 (target-matching, would yield reward=0.5) on both val and public_test splits. However, the hidden grader reported raw_score=0.49, corresponding to rollout_rel_l2 ≈ 0.0020+, well above the 0.0016 target threshold. The agent's model generalizes well to public_test (per agent's rollout_eval.py: 0.0012 mean / 0.0018 final) but failed on the hidden distribution. Verification script confirms metric definition matches agent's computation (line 170: rel_l2 = ((diff.pow(2).sum(-1).sqrt()) / (targets.pow(2).sum(-1).sqrt())).mean()).
Root causeThe agent's multi-step rollout training approach with curriculum and augmentation successfully approached golden-reference performance on local test splits, but the learned model failed to generalize to the hidden evaluation distribution. This is a model generalization failure, not a specification problem, the task is well-defined with clear metrics and baselines.
RecommendationN/A - task is fine. The agent's sophisticated approach (multi-step rollout curriculum, symmetry augmentation, EMA smoothing) was sound and nearly matched the reference solution on available data. The failure stems from the model not generalizing to out-of-distribution hidden test data, which is a model/training issue, not a task issue. Future attempts should consider: (1) regularization to improve OOD robustness, (2) testing on more diverse trajectory initializations, or (3) ensemble methods to reduce variance.
Trajectory
Tool-by-tool agent trajectory
201 tool calls · 3 tool types · 201 steps
# Kuramoto-Sivashinsky 1D Forecasting Train a neural surrogate to forecast the 1D Kuramoto-Sivashinsky equation: u_t + u*u_x + u_xx + u_xxxx = 0 on x in [0, L] periodic, L=22 This equation produces spatiotemporal chaos , small errors compound quickly over the rollout. ## What You Predict Given the last k=4 frames as input window [B, 4, 128], predict the next single frame [B, 1, 128]. At evaluation the hidden grader rolls your model autoregressively for 20 steps and scores the full rollout. ## Files Available - `/app/data/train/trajectories.pt` , 200 trajectories, shape [200, 100, 128] - `/app/data/val/trajectories.pt` , 32 trajectories - `/app/data/public_test/trajectories.pt` , 16 trajectories - `/app/task_config.json` , model config, training defaults - `/app/feature_schema.json` , grid spec and channel definitions - `/app/candidate_model.py` , fixed FNO-1D architecture - `/app/dataset.py` , KSForecast dataset yielding (window, next_frame) pairs - `/app/train.py` , weak baseline training script ## What To Do Improve the training recipe. You may change loss, optimizer, scheduler, augmentation, EMA, epochs. The checkpoint must be compatible with build_model(config) in candidate_model.py. Save your checkpoint to `/app/outputs/model.pt`. ## Output Contract model.pt must be a dict loadable with torch.load(..., weights_only=True) containing: - state_dict , state dict matching build_model(task_config) - feat_mean, feat_std , float scalars for input/output standardization ## Local Training ```bash python3 /app/train.py TASK_EPOCHS_OVERRIDE=2 python3 /app/train.py ```
Let me start by exploring the environment to understand the task setup.
I'll start by exploring the environment to understand the task setup, the provided files, and the architecture I need to work with.
bash
cd /app && ls -la && echo "---- nvidia ----" && nvidia-smi 2>/dev/null || echo "no gpu"; echo "---- python ----"; python3 --version; python3 -c "import torch; print('torch', torch.__version__, 'cuda', torch.cuda.is_available())"
output
total 15
drwxrws--- 3 h2tagent h2tagent  138 Jun 19 18:00 .
drwxr-xr-x 1 root     root     4096 Jun 20 07:11 ..
-rw-rw---- 1 h2tagent h2tagent 2710 Jun 19 17:59 candidate_model.py
drwxrws--- 5 h2tagent h2tagent   58 Jun 19 17:59 data
-rw-rw---- 1 h2tagent h2tagent 1195 Jun 19 17:59 dataset.py
-rw-rw---- 1 h2tagent h2tagent  238 Jun 19 17:59 feature_schema.json
-rw-rw---- 1 h2tagent h2tagent  633 Jun 19 17:59 task_config.json
-rw-rw---- 1 h2tagent h2tagent 3184 Jun 19 17:59 train.py
---- nvidia ----
Sat Jun 20 07:11:30 2026       
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 580.82.07              Driver Version: 580.82.07      CUDA Version: 13.0     |
+-----------------------------------------+------------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA H100 80GB HBM3          Off |   N/A              Off |                    0 |
| N/A   33C    P0            124W /  700W |    5685MiB /  81559MiB |      1%      Default |
|                                         |                        |             Disabled |
+-----------------------------------------+------------------------+----------------------+

+-----------------------------------------------------------------------------------------+
| Processes:                                                                              |
|  GPU   GI   CI              PID   Type   Process name                        GPU Memory |
|        ID   ID                                                               Usage      |
|=========================================================================================|
|  No running processes found                                                             |
+-----------------------------------------------------------------------------------------+
---- python ----
Python 3.11.10
torch 2.5.1+cu124 cuda True
I have an H100 GPU with 80GB memory and PyTorch 2.5.1 with CUDA. Let me explore the provided files.
I have an H100 GPU available. Let me examine all the provided files to understand the architecture, data, and baseline recipe.
bash
cd /app && echo "==== task_config.json ====" && cat task_config.json && echo && echo "==== feature_schema.json ====" && cat feature_schema.json && echo && echo "==== candidate_model.py ====" && cat candidate_model.py
output
==== task_config.json ====
{
  "task_id": "ks-equation-1d-forecast",
  "dataset_name": "ks-equation-1d-chaotic",
  "feature_format": "trajectory-window-k-frames",
  "label_format": "next-frame",
  "grid_size": 128,
  "in_channels": 4,
  "out_channels": 1,
  "rollout_horizon": 20,
  "seed": 20260517,
  "model": {
    "width": 32,
    "modes": 16,
    "num_layers": 4
  },
  "training": {
    "epochs": 10,
    "batch_size": 64,
    "lr": 0.001,
    "weight_decay": 0.0001,
    "loss": "MSE"
  },
  "evaluation": {
    "primary_metric": "rollout_rel_l2_score",
    "secondary_metrics": [
      "rollout_rmse_score",
      "final_step_rel_l2_score"
    ]
  }
}

==== feature_schema.json ====
{
  "domain": "1d-periodic",
  "grid_size": 128,
  "domain_length": 22.0,
  "dt_effective": 0.25,
  "input": {"channels": 4, "description": "last k=4 frames of u(x,t)"},
  "output": {"channels": 1, "description": "next frame u(x,t+1)"}
}

==== candidate_model.py ====
from __future__ import annotations
from typing import Mapping
import torch
import torch.nn as nn


class SpectralConv1d(nn.Module):
    def __init__(self, in_channels: int, out_channels: int, modes: int) -> None:
        super().__init__()
        self.in_channels = in_channels
        self.out_channels = out_channels
        self.modes = modes
        scale = 1.0 / (in_channels * out_channels)
        self.weight = nn.Parameter(
            scale * torch.randn(in_channels, out_channels, modes, dtype=torch.cfloat)
        )

    @staticmethod
    def _mul1d(inp: torch.Tensor, weight: torch.Tensor) -> torch.Tensor:
        return torch.einsum("bix,iox->box", inp, weight)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        b, _, n = x.shape
        x_ft = torch.fft.rfft(x, norm="ortho")
        out_ft = torch.zeros(b, self.out_channels, n // 2 + 1, dtype=torch.cfloat, device=x.device)
        m = min(self.modes, x_ft.shape[-1])
        out_ft[:, :, :m] = self._mul1d(x_ft[:, :, :m], self.weight[:, :, :m])
        return torch.fft.irfft(out_ft, n=n, norm="ortho")


class FNO1dBlock(nn.Module):
    def __init__(self, width: int, modes: int) -> None:
        super().__init__()
        self.spectral = SpectralConv1d(width, width, modes)
        self.bypass = nn.Conv1d(width, width, 1)
        self.act = nn.GELU()

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        return self.act(self.spectral(x) + self.bypass(x))


class FNO1d(nn.Module):
    def __init__(self, in_channels: int, out_channels: int, width: int, modes: int, num_layers: int, grid_size: int) -> None:
        super().__init__()
        self.lift = nn.Conv1d(in_channels + 1, width, 1)
        self.blocks = nn.ModuleList(FNO1dBlock(width, modes) for _ in range(num_layers))
        self.proj = nn.Sequential(
            nn.Conv1d(width, width, 1),
            nn.GELU(),
            nn.Conv1d(width, out_channels, 1),
        )
        self.register_buffer("_grid", torch.linspace(0.0, 1.0, grid_size + 1)[:grid_size].view(1, 1, grid_size), persistent=False)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        b = x.shape[0]
        grid = self._grid.expand(b, -1, -1).to(x.device, dtype=x.dtype)
        x = torch.cat([x, grid], dim=1)
        x = self.lift(x)
        for block in self.blocks:
            x = block(x)
        return self.proj(x)


def build_model(config: Mapping) -> FNO1d:
    m = config["model"]
    return FNO1d(
        in_channels=int(config["in_channels"]),
        out_channels=int(config["out_channels"]),
        width=int(m["width"]),
        modes=int(m["modes"]),
        num_layers=int(m["num_layers"]),
        grid_size=int(config["grid_size"]),
    )
Now let me look at the dataset and the baseline training script:
bash
cd /app && echo "==== dataset.py ====" && cat dataset.py && echo && echo "==== train.py ====" && cat train.py
output
==== dataset.py ====
from __future__ import annotations
from pathlib import Path
import torch
from torch.utils.data import Dataset


class KSForecast(Dataset):
    def __init__(self, split_dir: str | Path, k: int = 4) -> None:
        self.dir = Path(split_dir)
        self.k = int(k)
        payload = torch.load(self.dir / "trajectories.pt", map_location="cpu", weights_only=True)
        self.trajectories: torch.Tensor = payload["trajectories"].float()
        n_traj, t_stored, _ = self.trajectories.shape
        if t_stored <= self.k:
            raise ValueError(f"trajectories too short for k={self.k}: t_stored={t_stored}")
        self._index = [(i, t) for i in range(n_traj) for t in range(self.k, t_stored)]

    def __len__(self) -> int:
        return len(self._index)

    def __getitem__(self, idx: int) -> dict:
        i, t = self._index[idx]
        return {
            "window": self.trajectories[i, t - self.k : t],
            "next_frame": self.trajectories[i, t : t + 1],
        }


def compute_standardization(trajectories: torch.Tensor) -> tuple[float, float]:
    mean = float(trajectories.mean().item())
    std = float(trajectories.std().clamp_min(1e-6).item())
    return mean, std

==== 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(Path(__file__).resolve().parent))
from candidate_model import build_model
from dataset import KSForecast, compute_standardization


def main() -> None:
    with (APP_DIR / "task_config.json").open() as fh:
        cfg = json.load(fh)

    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    torch.manual_seed(int(cfg["seed"]))
    k = int(cfg["in_channels"])

    train_ds = KSForecast(APP_DIR / "data" / "train", k=k)
    val_ds   = KSForecast(APP_DIR / "data" / "val",  k=k)
    feat_mean, feat_std = compute_standardization(train_ds.trajectories)

    model  = build_model(cfg).to(device)
    epochs = int(os.environ.get("TASK_EPOCHS_OVERRIDE", cfg["training"]["epochs"]))
    batch_size = int(cfg["training"]["batch_size"])
    lr         = float(cfg["training"]["lr"])
    optim  = torch.optim.AdamW(model.parameters(), lr=lr, weight_decay=float(cfg["training"]["weight_decay"]))
    sched  = torch.optim.lr_scheduler.CosineAnnealingLR(optim, T_max=max(1, epochs))

    def normalize(t): return (t - feat_mean) / feat_std

    idx    = torch.tensor(train_ds._index, dtype=torch.long)
    traj   = train_ds.trajectories
    t_idx  = idx[:, 1]
    offsets = torch.arange(-k, 0)
    train_x = traj[idx[:, 0].unsqueeze(1).expand(-1, k), t_idx.unsqueeze(1) + offsets]
    train_y = traj[idx[:, 0], t_idx].unsqueeze(1)

    idx_v   = torch.tensor(val_ds._index, dtype=torch.long)
    traj_v  = val_ds.trajectories
    t_idx_v = idx_v[:, 1]
    val_x   = traj_v[idx_v[:, 0].unsqueeze(1).expand(-1, k), t_idx_v.unsqueeze(1) + offsets]
    val_y   = traj_v[idx_v[:, 0], t_idx_v].unsqueeze(1)

    print(f"[train] device={device} epochs={epochs} pairs={len(train_ds)}", flush=True)

    for epoch in range(epochs):
        model.train()
        perm = torch.randperm(train_x.shape[0])
        running, n_batches = 0.0, 0
        for start in range(0, train_x.shape[0], batch_size):
            idx_b = perm[start:start + batch_size]
            xb = normalize(train_x[idx_b]).to(device)
            yb = normalize(train_y[idx_b]).to(device)
            optim.zero_grad(set_to_none=True)
            loss = F.mse_loss(model(xb), yb)
            loss.backward()
            optim.step()
            running += loss.item()
            n_batches += 1
        sched.step()
        with torch.no_grad():
            model.eval()
            pred = model(normalize(val_x).to(device)).cpu() * feat_std + feat_mean
            val_rl2 = ((pred - val_y).pow(2).sum(-1).sqrt() / val_y.pow(2).sum(-1).sqrt().clamp_min(1e-8)).mean().item()
       
…[truncated]
Now I understand the setup. Let me analyze the data to understand its structure and statistics. Key observations: 1. The model is a fixed FNO-1D architecture with width=32, modes=16, num_layers=4. I can't change it (the checkpoint must be compatible with build_model). 2. Input is [B, 4, 128] (last 4 frames), output is [B, 1, 128] (next frame). 3. At eval, the grader rolls autoregressively for 20 steps, scoring the full rollout with rollout_rel_l2_score. 4. The baseline trains with single-step MSE only , this is suboptimal for autoregressive rollout because errors compound. The key insight: the baseline uses single-step MSE training, which does not account for error accumulation during autoregressive rollout. The standard fix is **multi-step / pushforward training**: during training, roll the model out for several steps and penalize the accumulated error. This makes the model robust to its own distribution shift. Let me think about what improvements to make: 1. **Multi-step rollout training (pushforward trick)**: Train the model to predict multiple steps ahead autoregressively, backpropagating through the rollout (or using the pushforward trick where gradients only flow through the last step). This directly targets the rollout metric. 2. **Loss function**: Use relative L2 loss (which matches the eval metric) instead of plain MSE. Could also add a spectral/derivative loss. 3. **Optimizer/scheduler**: AdamW with cosine annealing + warmup. 4. **EMA**: Exponential moving average of weights for stability. 5. **More epochs**: The baseline uses 10 epochs. 6. **Data augmentation**: The KS equation on a periodic domain is translation-invariant, so random spatial shifts (circular) are a valid augmentation. Also, the KS equation has a reflection symmetry: if u(x,t) is a solution, then -u(-x,t) is also a solution. Let me verify this. Let me check the reflection symmetry of the KS equation: u_t + u*u_x + u_xx + u_xxxx = 0 Under x -> -x: Let v(x,t) = u(-x,t). Then v_x = -u_x(-x), v_xx = u_xx(-x), v_xxxx = u_xxxx(-x). And v*v_x = u(-x)*(-u_x(-x)) = -u*u_x(-x). So v_t + v*v_x + v_xx + v_xxxx = u_t(-x) - u*u_x(-x) + u_xx(-x) + u_xxxx(-x). That's not zero. Now consider w(x,t) = -u(-x,t). w_t = -u_t(-x). w_x = -(-u_x(-x)) = u_x(-x)... wait let me be careful. w(x) = -u(-x). dw/dx = -u'(-x)*(-1) = u'(-x) = u_x(-x). w_xx = d/dx[u_x(-x)] = u_xx(-x)*(-1) = -u_xx(-x). Hmm, let me redo. Let w(x) = -u(-x). - w'(x) = -u'(-x) * (-1) = u'(-x). - w''(x) = d/dx[u'(-x)] = u''(-x)*(-1) = -u''(-x). - w'''(x) = d/dx[-u''(-x)] = -u'''(-x)*(-1) = u'''(-x). - w''''(x) = d/dx[u'''(-x)] = u''''(-x)*(-1) = -u''''(-x). Hmm, that gives w_xx = -u_xx(-x) and w_xxxx = -u_xxxx(-x). w_t = -u_t(-x). w*w_x = (-u(-x))*(u_x(-x)) = -u*u_x(-x). So w_t + w*w_x + w_xx + w_xxxx = -u_t(-x) - (u*u_x)(-x) - u_xx(-x) - u_xxxx(-x) = -[u_t + u*u_x + u_xx + u_xxxx](-x) = 0. So w(x,t) = -u(-x,t) IS a solution. So the reflection symmetry is u(x,t) -> -u(-x,t). This is a valid data augmentation: flip the spatial axis AND negate the values. Also translation invariance: u(x,t) -> u(x - c, t) is a solution (periodic domain). So circular shifts along the spatial axis are valid augmentations. These symmetries can be used for augmentation and will help generalization. Let me think about the main strategy. The most important thing for rollout stability in autoregressive neural PDE solvers is multi-step training. Let me implement: 1. **Pushforward / multi-step rollout loss**: The training dataset gives (window of k frames, next frame). To do multi-step training, I need consecutive frames. I'll build sequences from trajectories directly. For each trajectory of length 100, I can sample a starting window of 4 frames and then roll out for M steps, comparing each predicted frame to ground truth. Actually the cleanest approach: load the raw trajectories [N, 100, 128]. For training I'll create windows and do rollout within the trajectory. Let me think about the window update during rollout …[truncated]
Now let me inspect the actual data to understand its statistics and structure.
bash
cd /app && python3 -c "
import torch
for split in ['train','val','public_test']:
    p = f'data/{split}/trajectories.pt'
    payload = torch.load(p, map_location='cpu', weights_only=True)
    print('====', split, '====')
    print('keys:', list(payload.keys()))
    tr = payload['trajectories']
    print('shape', tr.shape, 'dtype', tr.dtype)
    print('mean %.5f std %.5f min %.3f max %.3f' % (tr.mean(), tr.std(), tr.min(), tr.max()))
"
output
==== train ====
keys: ['trajectories']
shape torch.Size([200, 100, 128]) dtype torch.float32
mean -0.00000 std 1.15997 min -3.245 max 3.248
==== val ====
keys: ['trajectories']
shape torch.Size([32, 100, 128]) dtype torch.float32
mean -0.00000 std 1.13391 min -3.197 max 3.210
==== public_test ====
keys: ['trajectories']
shape torch.Size([16, 100, 128]) dtype torch.float32
mean 0.00000 std 1.22519 min -3.172 max 3.183
The data is roughly mean 0, std ~1.16. Let me understand the temporal dynamics better - how fast does the state decorrelate, and what does a 20-step rollout look like in terms of relative L2 if I just persist the last frame (persistence baseline)?
Let me understand the temporal dynamics , how quickly frames decorrelate, and establish simple baselines (persistence) for the 20-step rollout metric.
bash
cd /app && python3 -c "
import torch
tr = torch.load('data/val/trajectories.pt', map_location='cpu', weights_only=True)['trajectories']
# relative L2 between frame t and t+lag, averaged
def rel_l2(a,b):
    return ((a-b).pow(2).sum(-1).sqrt() / b.pow(2).sum(-1).sqrt().clamp_min(1e-8)).mean().item()
print('rel_l2 frame t vs t+1 :', rel_l2(tr[:,:-1], tr[:,1:]))
print('rel_l2 frame t vs t+5 :', rel_l2(tr[:,:-5], tr[:,5:]))
print('rel_l2 frame t vs t+20:', rel_l2(tr[:,:-20], tr[:,20:]))
# persistence rollout: predict next = last frame, 20 steps from t0=4
# window last frame is frame index 3, predict frames 4..23 all equal frame 3
N,T,X = tr.shape
import numpy as np
scores=[]
for start in range(4, T-20):
    last = tr[:, start-1:start]  # frame start-1
    gt = tr[:, start:start+20]
    pred = last.expand(-1,20,-1)
    r = ((pred-gt).pow(2).sum(-1).sqrt()/gt.pow(2).sum(-1).sqrt().clamp_min(1e-8)).mean().item()
    scores.append(r)
print('persistence 20-step rollout mean rel_l2:', np.mean(scores))
"
output
rel_l2 frame t vs t+1 : 0.03409876674413681
rel_l2 frame t vs t+5 : 0.16701358556747437
rel_l2 frame t vs t+20: 0.5774152874946594
persistence 20-step rollout mean rel_l2: 0.3212855344540195
So frame-to-frame relative L2 is ~3.4%. After 20 steps, two true frames are ~58% apart. Persistence over 20-step rollout gives ~0.32 mean rel L2. The dt_effective is 0.25, so each step is a small time step. The frames are highly correlated step-to-step (3.4% change). Now let me understand the scoring. The eval metric is "rollout_rel_l2_score". The name has "_score" , it might be a score where higher is better (like 1 - rel_l2 or exp(-rel_l2)), or it might just be the rel_l2 where lower is better. Let me not worry too much; I want to minimize rollout rel L2 regardless. Let me establish what the baseline train.py achieves first. Let me run it with a couple epochs to get a baseline, and also build a proper rollout evaluation harness that mimics the grader (20-step autoregressive rollout). Let me first write a rollout evaluation function that I'll use throughout. The grader: given last 4 frames, roll autoregressively 20 steps, score full rollout with rel L2. I need to define exactly how the rollout is scored. Likely: for each test trajectory, take an initial window (first 4 frames), predict frames 4..23, compare to ground truth frames 4..23, compute relative L2 per step and average over steps and trajectories. The "final_step_rel_l2" is the error at step 20. Let me set up a consistent local evaluation. I'll use the val set: initial window = frames [0:4], predict 20 steps → frames [4:24], compare to ground truth. Actually, I'm not 100% sure of the start index convention. But for model selection, what matters is a consistent rollout metric. I'll evaluate rollout starting at frame index 4 (using frames 0-3 as the initial window) predicting the next 20 frames (indices 4..23), averaging rel L2 over all 20 steps. I'll also compute multiple start positions to be robust. Let me make the local eval average over several start points to reduce variance and better reflect generalization. Let me first run the baseline to see where it lands. Let me build a shared eval utility and run the baseline quickly with 2 epochs.
Frames change ~3.4% per step; a 20-step rollout is a real challenge as errors compound. Let me quickly run the baseline to establish a reference, then build a proper autoregressive rollout evaluation harness.
bash
cd /app && mkdir -p outputs && TASK_EPOCHS_OVERRIDE=3 python3 train.py 2>&1 | tail -8
output
[train] device=cuda epochs=3 pairs=19200
[train] epoch=1/3 mse=6.0238e-02 val_rel_l2=0.0136
[train] epoch=2/3 mse=1.4463e-04 val_rel_l2=0.0079
[train] epoch=3/3 mse=8.2739e-05 val_rel_l2=0.0069
[train] wrote /app/outputs/model.pt
The single-step val rel L2 is ~0.007 already after 3 epochs, which is very low. But that's single-step. The real test is the 20-step autoregressive rollout. Let me build a rollout evaluator and measure what this baseline checkpoint actually achieves on rollout.
Single-step error is tiny (~0.007), but that's not what's graded. Let me build an autoregressive rollout evaluator matching the grader and measure the baseline's true 20-step rollout error.
bash
cd /app && cat > rollout_eval.py << 'EOF'
from __future__ import annotations
import json, os, sys
from pathlib import Path
import torch
sys.path.insert(0, '/app')
from candidate_model import build_model

def load_model(ckpt_path, cfg, device):
    ck = torch.load(ckpt_path, map_location='cpu', weights_only=True)
    model = build_model(cfg).to(device)
    model.load_state_dict(ck['state_dict'])
    model.eval()
    return model, float(ck['feat_mean']), float(ck['feat_std'])

@torch.no_grad()
def rollout_eval(model, feat_mean, feat_std, traj, device, k=4, horizon=20, starts=None):
    # traj: [N, T, X]. For each start s: window = frames [s-k:s], predict s..s+horizon-1
    N, T, X = traj.shape
    if starts is None:
        starts = list(range(k, T - horizon + 1))
    all_step_rl2 = []  # per-step rel l2 averaged over traj and starts
    final_rl2 = []
    rmse_all = []
    for s in starts:
        window = traj[:, s-k:s].to(device)  # [N,k,X]
        w = (window - feat_mean) / feat_std
        preds = []
        for h in range(horizon):
            p = model(w)  # [N,1,X] normalized
            preds.append(p)
            w = torch.cat([w[:, 1:], p], dim=1)
        pred = torch.cat(preds, dim=1) * feat_std + feat_mean  # [N,horizon,X]
        gt = traj[:, s:s+horizon].to(device)
        num = (pred - gt).pow(2).sum(-1).sqrt()
        den = gt.pow(2).sum(-1).sqrt().clamp_min(1e-8)
        rl2 = (num / den)  # [N, horizon]
        all_step_rl2.append(rl2.mean(0).cpu())  # [horizon]
        final_rl2.append(rl2[:, -1].mean().cpu())
        rmse = (pred - gt).pow(2).mean(-1).sqrt().mean(0).cpu()
        rmse_all.append(rmse)
    step_rl2 = torch.stack(all_step_rl2).mean(0)  # [horizon]
    rmse_step = torch.stack(rmse_all).mean(0)
    return {
        'mean_rollout_rel_l2': step_rl2.mean().item(),
        'final_step_rel_l2': step_rl2[-1].item(),
        'mean_rollout_rmse': rmse_step.mean().item(),
        'step_rl2': step_rl2.tolist(),
        'n_starts': len(starts),
    }

if __name__ == '__main__':
    cfg = json.load(open('/app/task_config.json'))
    device = 'cuda' if torch.cuda.is_available() else 'cpu'
    ckpt = sys.argv[1] if len(sys.argv) > 1 else '/app/outputs/model.pt'
    split = sys.argv[2] if len(sys.argv) > 2 else 'val'
    traj = torch.load(f'/app/data/{split}/trajectories.pt', map_location='cpu', weights_only=True)['trajectories'].float()
    model, fm, fs = load_model(ckpt, cfg, device)
    # Evaluation mimicking grader: use early start (window=first 4 frames)
    res_single = rollout_eval(model, fm, fs, traj, device, starts=[4])
    res_multi = rollout_eval(model, fm, fs, traj, device)
    print(f'== {split} ckpt={ckpt} ==')
    print('start=4  : mean_rl2=%.4f final=%.4f rmse=%.4f' % (res_single['mean_rollout_rel_l2'], res_single['final_step_rel_l2'], res_single['mean_rollout_rmse']))
    print('all starts(%d): mean_rl2=%.4f final=%.4f rmse=%.4f' % (res_multi['n_starts'], res_multi['mean_rollout_rel_l2'], res_multi['final_step_rel_l2'], res_multi['mean_rollout_rmse']))
    sr = res_multi['step_rl2']
    print('per-step rl2 [1,2,3,5,10,15,20]:', [round(sr[i],4) for i in [0,1,2,4,9,14,19]])
EOF
python3 rollout_eval.py /app/outputs/model.pt val
output
== val ckpt=/app/outputs/model.pt ==
start=4  : mean_rl2=0.0255 final=0.0443 rmse=0.0311
all starts(77): mean_rl2=0.0240 final=0.0444 rmse=0.0278
per-step rl2 [1,2,3,5,10,15,20]: [0.0067, 0.008, 0.0091, 0.0131, 0.0222, 0.0326, 0.0444]
Interesting! So the baseline (3 epochs) already achieves a 20-step rollout mean rel L2 of ~0.024, with final step ~0.044. This is much better than persistence (0.32). The single-step error compounds but not catastrophically here because the time step is small. Wait, this is the 3-epoch baseline. Let me run the full 10-epoch baseline to get the real reference. Let me also note the per-step growth: it grows roughly linearly from 0.0067 at step 1 to 0.0444 at step 20. So error compounds. The task is to reduce the rollout error. Let me get the full baseline (10 epochs) as reference. Let me run the full baseline.
The 3-epoch baseline gets ~0.024 mean rollout rel L2. Let me get the full 10-epoch baseline as the true reference point, saving it separately.
bash
cd /app && python3 train.py 2>&1 | tail -12 && cp outputs/model.pt outputs/baseline_10ep.pt && python3 rollout_eval.py outputs/baseline_10ep.pt val
output
[train] device=cuda epochs=10 pairs=19200
[train] epoch=1/10 mse=6.0238e-02 val_rel_l2=0.0136
[train] epoch=2/10 mse=1.3373e-04 val_rel_l2=0.0076
[train] epoch=3/10 mse=6.1280e-05 val_rel_l2=0.0058
[train] epoch=4/10 mse=3.6445e-05 val_rel_l2=0.0046
[train] epoch=5/10 mse=2.4894e-05 val_rel_l2=0.0038
[train] epoch=6/10 mse=1.8479e-05 val_rel_l2=0.0034
[train] epoch=7/10 mse=1.4761e-05 val_rel_l2=0.0032
[train] epoch=8/10 mse=1.2601e-05 val_rel_l2=0.0030
[train] epoch=9/10 mse=1.1432e-05 val_rel_l2=0.0029
[train] epoch=10/10 mse=1.0889e-05 val_rel_l2=0.0028
[train] wrote /app/outputs/model.pt
== val ckpt=outputs/baseline_10ep.pt ==
start=4  : mean_rl2=0.0099 final=0.0192 rmse=0.0122
all starts(77): mean_rl2=0.0093 final=0.0176 rmse=0.0108
per-step rl2 [1,2,3,5,10,15,20]: [0.0026, 0.0031, 0.0035, 0.005, 0.0085, 0.0127, 0.0176]
Now the full 10-epoch baseline gets: - start=4: mean_rl2=0.0099, final=0.0192 - all starts: mean_rl2=0.0093, final=0.0176 So my target is to beat mean_rl2 ≈ 0.0093-0.0099 and final ≈ 0.0176-0.0192. The single-step val rel L2 is 0.0028 and it keeps improving. More epochs of single-step training would help, but the key lever is rollout-aware (multi-step) training, which directly targets the compounding error. Let me think about the strategy: 1. **Multi-step rollout training**: Train by unrolling the model for M steps and computing loss against ground truth at each step. This is the single biggest lever for rollout accuracy. 2. **Loss**: Use relative L2 (matches eval) or a combination. Actually, for the gradient behavior, let me think. The eval metric is rel L2. Training directly on rel L2 (per sample) aligns train and eval. But MSE in normalized space also works. Let me use a combination: primarily relative L2 summed over the rollout. 3. **Data augmentation using symmetries**: - Translation (circular shift): valid on periodic domain. Shift all frames in a window+target by the same random amount. - Reflection + negation: u(x,t) -> -u(-x,t). Valid symmetry. Flip spatial axis and negate. These augmentations effectively increase data diversity. Since the model has a grid feature appended (positional), circular shift is a genuine augmentation (not trivially invariant). Wait , the model appends a grid coordinate (linspace 0..1). So it's NOT translation equivariant by construction (the grid breaks it). So translation augmentation genuinely helps. Good. Actually, hmm, does adding the grid help or hurt? The grid is fixed. For a translation-invariant PDE, the solution operator is translation equivariant, so ideally the model shouldn't depend on absolute position. But the architecture includes the grid. I can't change the architecture. But augmentation with random shifts will encourage the model to learn translation-equivariant behavior despite the grid input, effectively teaching it to ignore the grid. That's good for generalization. 4. **EMA**: Exponential moving average of weights , helps stability and final performance. 5. **Optimizer/scheduler**: AdamW + cosine with warmup. Maybe more epochs. 6. **More epochs**: with multi-step training each epoch is more expensive, but on H100 with this tiny model it's fine. Let me think carefully about multi-step training design to maximize rollout accuracy while staying stable. Approach: For each training sample, I need a window of k=4 consecutive frames and then M subsequent ground-truth frames. From trajectories [N, 100, 128], valid start indices s (the first predicted frame) range from k=4 to T-M. I sample (trajectory, s) pairs. Training step: - window = frames [s-k : s] (normalized) - for h in 0..M-1: pred = model(window); loss += rel_l2(pred*fs+fm vs gt[s+h]); window = cat(window[:,1:], pred) - backprop through the full unrolled graph. Curriculum: Start M=1 for warmup epochs, then increase M (e.g., 2, 4, 6, 8). This stabilizes early training and then builds rollout robustness. Full BPTT through M steps. The pushforward trick (Brandstetter): instead of backprop through all steps, you unroll with no_grad for a random number of steps to bring the input onto the model's own distribution, then do ONE step with gradient. This prevents the model from relying on its own corrections in a way that causes instability, and is cheaper. But full BPTT over a few steps tends to give better accuracy for short horizons. Given horizon=20 at eval, I want the model robust over 20 steps. Training with M up to ~8-10 with full BPTT plus the distribution-shift exposure should generalize to 20. Let me combine: use multi-step with full BPTT, and also consider a pushforward component. Actually, let me think about potential issues with full BPTT on rel L2 loss: rel L2 has a division; for chaotic signals the denominator (norm of gt frame) is ~ sqrt(128)*1.16 ≈ 13, never near zero, so it's …[truncated]
Now I have my reference: the full baseline gets **mean rollout rel L2 ≈ 0.0093** (final step ≈ 0.0176). My job is to beat that. Since the grader rolls autoregressively, the key lever is **rollout-aware (multi-step) training**. Let me first check the data's spectral content to confirm the model's 16 Fourier modes are adequate.
bash
cd /app && python3 -c "
import torch
tr = torch.load('data/train/trajectories.pt', map_location='cpu', weights_only=True)['trajectories'].float()
# energy per fourier mode (rfft along x)
ft = torch.fft.rfft(tr, dim=-1, norm='ortho')  # [N,T,65]
energy = ft.abs().pow(2).mean(dim=(0,1))  # [65]
cum = torch.cumsum(energy, 0) / energy.sum()
print('num rfft modes:', energy.shape[0])
print('cumulative energy fraction at modes [4,8,12,16,20,24,32]:')
for m in [4,8,12,16,20,24,32,64]:
    print('  modes<=%2d : %.5f' % (m, cum[m].item() if m < len(cum) else 1.0))
print('energy beyond mode 16 fraction: %.5e' % (1 - cum[16].item()))
# mean frame norm
print('mean ||frame||_2:', tr.pow(2).sum(-1).sqrt().mean().item())
"
output
num rfft modes: 65
cumulative energy fraction at modes [4,8,12,16,20,24,32]:
  modes<= 4 : 0.97440
  modes<= 8 : 1.00000
  modes<=12 : 1.00000
  modes<=16 : 1.00000
  modes<=20 : 1.00000
  modes<=24 : 1.00000
  modes<=32 : 1.00000
  modes<=64 : 1.00000
energy beyond mode 16 fraction: 0.00000e+00
mean ||frame||_2: 12.913924217224121
Excellent! Essentially ALL energy is in the first 8 modes (99.99%+ by mode 8). The 16 modes in the FNO is more than enough. So the architecture's spectral capacity is not a bottleneck at all. This is important: the solution is very smooth (L=22 is a relatively small box, so only a few active modes). This means the model can represent the dynamics well. The challenge is purely the chaotic error accumulation. Mean frame norm is ~12.9. So rel L2 = ||err||/12.9. Now, since energy is concentrated in ~8 modes, the problem is effectively low-dimensional. The model should be able to learn it very accurately. The question is pure rollout stability. Let me design the improved training. Key components: 1. Multi-step rollout training with curriculum + full BPTT. 2. Symmetry augmentation (translation via circular shift, reflection+negation). 3. EMA. 4. AdamW + cosine schedule with warmup. 5. Relative L2 loss (match eval). 6. More epochs. Let me think about the data layout for efficient multi-step training. Trajectories: train [200,100,128]. I'll move the whole tensor to GPU (200*100*128*4 bytes = 10MB, tiny). Then build an index of valid starts for a given max rollout M: s in [k, T-M]. For each batch, gather windows and the M future frames. Actually, a cleaner and more flexible approach: precompute nothing; just sample (i, s) and slice. With everything on GPU, slicing is fast. Let me write the training script. I'll make the rollout length M a curriculum parameter. Design decisions for augmentation: - Circular shift: roll along x-axis by random integer for each sample. Apply SAME shift to window and all targets. This is exact for periodic data on the grid (128 points). Shift amount random in [0,128). - Reflection+negation: with prob 0.5, x -> flipped, values negated. For discrete periodic grid: u(x,t) -> -u(-x,t). On grid indices, -x mod 128: that's flip then roll by 1? Let me be careful. Continuous: v(x) = -u(-x). On grid x_j = j*dx, v_j = -u(-x_j) = -u(x_{-j mod N}). So v_j = -u[(N - j) mod N]. That is: v[0] = -u[0], v[1] = -u[N-1], v[2] = -u[N-2], ..., i.e. v = -u reversed with a roll. Specifically, reversing u gives r[j]=u[N-1-j]. We want w[j]=u[(N-j)mod N]. w[0]=u[0], w[j]=u[N-j] for j>=1. So w = u[0], u[N-1], u[N-2], ..., u[1]. That's roll(flip(u, shift... hmm. Actually the simplest: since I'm ALSO doing random circular shifts by arbitrary amounts, the exact alignment of the reflection (whether it's off by one grid cell) doesn't matter , a reflection composed with an arbitrary shift covers the same augmentation set. The KS dynamics are symmetric under continuous translation, which on the grid we approximate by integer-cell shifts (exact for band-limited signals sampled on the grid, which these are since energy is in low modes , shifting by integer cells is exact; shifting by non-integer would need spectral interpolation). Hmm, actually integer-cell circular shift is EXACT for any periodic grid function (it's just relabeling). And it corresponds to continuous translation by j*dx only approximately unless band-limited. But for augmentation validity, what matters is: is the shifted trajectory still a valid solution sampled on the grid? Continuous translation by j*dx of the continuous solution, sampled on grid = circular shift by j of the sampled solution, ONLY if no aliasing. Since the field is band-limited well below Nyquist (energy in modes <=8, Nyquist is mode 64), sampling commutes with translation. So circular shift by integer j exactly equals sampling the translated continuous solution. Valid augmentation. For reflection: flip with negation. r[j] = -u[N-1-j] corresponds to continuous -u(L - dx - x)? Let me not overthink; combined with arbitrary shifts, the reflect-and-negate augmentation gives valid solutions up to a half-cell shift which is absorbed. Actually to be safe and exact, let me implement reflection as v[j] = -u[(N-j) mod N] which is the exact grid reflection about x=0. Let me implement via: flip then roll …[truncated]
Key finding: **99.99% of the energy is in the first ~8 Fourier modes** , the model's 16 modes are more than enough, and the field is very smooth. So the architecture is not the bottleneck; the entire challenge is **error accumulation during autoregressive rollout**. This tells me the winning strategy is: 1. **Multi-step rollout training** (curriculum on horizon) so the model sees its own predictions and learns to suppress compounding error , directly targeting the graded metric. 2. **Symmetry-based augmentation** , the KS equation on a periodic domain is invariant under translation (circular shift) and the reflection map u(x,t) → −u(−x,t). Let me verify that symmetry numerically before relying on it.
bash
cd /app && python3 -c "
import torch
# Verify reflect+negate symmetry: if u(x,t) solves KS, so does -u(-x,t).
# Test via spectral time-derivative residual on real data consistency:
# Instead, check that transformed trajectory is dynamically consistent by
# comparing one-step finite-difference operators' statistics (sanity proxy).
tr = torch.load('data/train/trajectories.pt', map_location='cpu', weights_only=True)['trajectories'].float()
L=22.0; N=128; dx=L/N
u = tr[0,50]  # a frame
# build spatial derivatives via spectral
k = 2*torch.pi*torch.fft.rfftfreq(N, d=dx)
def deriv(u, order):
    uf = torch.fft.rfft(u)
    return torch.fft.irfft((1j*k)**order * uf, n=N)
# KS RHS: -u*u_x - u_xx - u_xxxx
def rhs(u):
    return -(u*deriv(u,1) + deriv(u,2) + deriv(u,4))
r1 = rhs(u)
# transform w(x) = -u(-x): grid reflection about origin = -roll(flip(u),1)
w = -torch.roll(torch.flip(u, dims=[-1]), shifts=1, dims=-1)
rw = rhs(w)
# w's rhs should equal the transform of r1: (R r1)(x) = -r1(-x) = -roll(flip(r1),1)
r1_transformed = -torch.roll(torch.flip(r1, dims=[-1]), shifts=1, dims=-1)
print('reflect-negate symmetry residual (should be ~0):', (rw - r1_transformed).abs().max().item())
# translation: shift by s cells -> rhs shifts by s cells
s=7
us = torch.roll(u, shifts=s, dims=-1)
print('translation symmetry residual (should be ~0):', (rhs(us) - torch.roll(r1, shifts=s, dims=-1)).abs().max().item())
"
output
reflect-negate symmetry residual (should be ~0): 0.015765637159347534
translation symmetry residual (should be ~0): 0.010350704193115234
Both residuals are small (~0.01, relative to RHS magnitudes that are much larger). Let me check the magnitude of the RHS to confirm these residuals are negligibly small (numerical, from discrete spectral derivatives of order 4). Actually the residuals ~0.01 compared to rhs magnitude , let me check rhs magnitude.
Both symmetry residuals are tiny. Let me confirm they're negligible relative to the RHS magnitude (the small nonzero values are just spectral round-off on the 4th derivative).
bash
cd /app && python3 -c "
import torch
tr = torch.load('data/train/trajectories.pt', map_location='cpu', weights_only=True)['trajectories'].float()
L=22.0; N=128; dx=L/N
u = tr[0,50]
k = 2*torch.pi*torch.fft.rfftfreq(N, d=dx)
def deriv(u, order):
    return torch.fft.irfft((1j*k)**order * torch.fft.rfft(u), n=N)
rhs = -(u*deriv(u,1)+deriv(u,2)+deriv(u,4))
print('RHS magnitude (max abs): %.3f, symmetry residual ~0.016 => relative %.2e' % (rhs.abs().max().item(), 0.016/rhs.abs().max().item()))
"
output
RHS magnitude (max abs): 0.755, symmetry residual ~0.016 => relative 2.12e-02
The relative residual is ~2% which is just from 4th-order spectral derivative round-off and the fact that I used a grid reflection (off by alignment). Both symmetries are valid. Good , I'll use both augmentations. Now let me write the improved training script. I'll make it configurable and evaluate variants. Let me design it carefully with all the components.
Both symmetries are confirmed valid (the ~2% residual is just 4th-derivative spectral round-off). Now I'll write a comprehensive, configurable training script implementing multi-step rollout training with a curriculum, symmetry augmentation, EMA, and warmup+cosine scheduling.
str_replace_based_edit_tool
command: create
path: /app/train_improved.py
file_text: from __future__ import annotations
import json, os, sys, math, copy, time
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
from dataset import compute_standardization
from rollout_eval import rollout_eval

# ----------------------------- config -----------------------------
def getenv_f(name, default):
    return float(os.environ.get(name, default))
def getenv_i(name, default):
    return int(os.environ.get(name, default))

CFG = json.load(open(APP_DIR / "task_config.json"))
DEVICE = torch.device("cuda" if torch.cuda.is_available() else "cpu")
K = int(CFG["in_channels"])          # 4 input frames
HORIZON = int(CFG["rollout_horizon"])  # 20 (eval)

EPOCHS      = getenv_i("EPOCHS", 80)
BATCH       = getenv_i("BATCH", 128)
LR          = getenv_f("LR", 1.5e-3)
WD          = getenv_f("WD", 1e-4)
WARMUP_FRAC = getenv_f("WARMUP_FRAC", 0.05)
EMA_DECAY   = getenv_f("EMA_DECAY", 0.9995)
GRAD_CLIP   = getenv_f("GRAD_CLIP", 1.0)
AUG         = getenv_i("AUG", 1)          # symmetry augmentation on/off
NOISE_STD   = getenv_f("NOISE_STD", 0.0)  # input noise (in normalized units)
MAX_M       = getenv_i("MAX_M", 10)       # max rollout length in curriculum
SEED        = getenv_i("SEED", int(CFG["seed"]))
TAG         = os.environ.get("TAG", "run")
LOSS        = os.environ.get("LOSS", "rel_l2")  # rel_l2 | mse
PUSHFWD     = getenv_i("PUSHFWD", 0)     # pushforward: unroll no-grad then grad on tail
SAVE_PATH   = os.environ.get("SAVE_PATH", str(APP_DIR / "outputs" / f"model_{TAG}.pt"))

torch.manual_seed(SEED)

# ----------------------------- data -----------------------------
def load_split(name):
    return torch.load(APP_DIR / "data" / name / "trajectories.pt",
                      map_location="cpu", weights_only=True)["trajectories"].float()

train_traj = load_split("train").to(DEVICE)   # [200,100,128]
val_traj   = load_split("val")                # keep on cpu; eval moves as needed
feat_mean, feat_std = compute_standardization(train_traj.cpu())
print(f"[{TAG}] feat_mean={feat_mean:.5f} feat_std={feat_std:.5f} device={DEVICE}", flush=True)

N, T, X = train_traj.shape
train_norm = (train_traj - feat_mean) / feat_std   # normalized, on GPU

# ----------------------------- augmentation -----------------------------
def augment(seq):
    """seq: [B, L, X] normalized frames. Apply KS symmetries.
    - reflect+negate: u(x) -> -u(-x)  (valid: -u(-x,t) solves KS)
    - random circular shift (translation on periodic domain)
    Same transform applied to all L frames of a sample."""
    B, L, Xl = seq.shape
    # reflect+negate with prob 0.5 (normalized mean~0 so negation is well-defined)
    do_ref = (torch.rand(B, device=seq.device) < 0.5)
    reflected = -torch.roll(torch.flip(seq, dims=[-1]), shifts=1, dims=-1)
    seq = torch.where(do_ref.view(B, 1, 1), reflected, seq)
    # random circular shift
    shifts = torch.randint(0, Xl, (B,), device=seq.device)
    ar = torch.arange(Xl, device=seq.device)
    idx = (ar.view(1, Xl) - shifts.view(B, 1)) % Xl           # [B,X]
    idx = idx.view(B, 1, Xl).expand(B, L, Xl)
    seq = torch.gather(seq, 2, idx)
    return seq

# ----------------------------- curriculum -----------------------------
def rollout_len_for_epoch(ep):
    # gradually grow the training rollout horizon
    frac = ep / max(1, EPOCHS - 1)
    if frac < 0.12:   return 1
    if frac < 0.25:   return 2
    if frac < 0.40:   return 4
    if frac < 0.55:   return 6
    if frac < 0.72:   return 8
    return MAX_M

# ----------------------------- model / optim -----------------------------
model = build_model(CFG).to(DEVICE)
ema = copy.deepcopy(model)
for p in ema.parameters():
    p.requires_grad_(False)

opt = torch.optim.AdamW(model.parameters(), lr=LR, weight_decay=WD, betas=(0.9, 0.99))

steps_per_epoch = math.ceil((N * (T - K - 1)) / BATC
…[truncated]
output
New file created successfully at /app/train_improved.py
Let me first do a quick smoke test with few epochs to make sure the script runs correctly, then run a proper experiment.
Let me smoke-test the script with a few epochs to verify correctness before committing to a full run.
bash
cd /app && EPOCHS=6 TAG=smoke SAVE_PATH=/app/outputs/model_smoke.pt python3 train_improved.py 2>&1 | tail -15
output
[smoke] feat_mean=-0.00000 feat_std=1.15997 device=cuda
[smoke] ep=2/6 M=2 loss=2.3291e-02 best_rl2=0.02331(final 0.04262 ema@2) lr=1.19e-03 t=9s
[smoke] ep=3/6 M=6 loss=2.0080e-02 best_rl2=0.01657(final 0.02921 ema@3) lr=8.25e-04 t=18s
[smoke] ep=4/6 M=8 loss=2.3564e-02 best_rl2=0.01411(final 0.02445 ema@4) lr=4.46e-04 t=29s
[smoke] ep=5/6 M=10 loss=1.5229e-02 best_rl2=0.01210(final 0.02079 ema@5) lr=1.53e-04 t=41s
[smoke] ep=6/6 M=10 loss=7.9869e-03 best_rl2=0.01052(final 0.01794 raw@6) lr=8.18e-06 t=54s
[smoke] SAVED /app/outputs/model_smoke.pt best_val_rollout_rel_l2=0.01052 final=0.01794 (raw@ep6)
The script works. In just 6 epochs it already gets close to the 10-epoch baseline (0.0105 vs 0.0093). With a proper longer run it should beat it. Each epoch at M=10 is ~12s; 80 epochs would be maybe ~12 min. Let me run the full 80-epoch run. Actually, let me reconsider the time. Epochs 1-6 took 54s but with increasing M. At M=10, ~12s/epoch. With 80 epochs, the later ones dominate; roughly say average 8s → ~11 min. That's fine. But let me think about whether I should run multiple variants in parallel or sequentially. Let me first run the main configuration (full BPTT, aug, EMA) for 80 epochs and see where it lands. Then try variants: pushforward, no-aug, different MAX_M, noise injection. Let me launch the main run in the background and capture logs, so I can monitor. Actually, given token budget, let me be strategic. Let me run the main 80-epoch run now in the foreground but tail the output. ~11 min is acceptable. Actually, let me run it in the background and poll, so I can do other things. Let me launch a few experiments. But to be careful about GPU contention, I'll run them sequentially. Let me start with the primary run. Let me reconsider hyperparameters before the big run: - EPOCHS=80, LR=1.5e-3, MAX_M=10, AUG=1, EMA=0.9995, full BPTT. One concern: with full BPTT over M=10 and rel_l2 loss summed/averaged, is it stable? The smoke test showed stable decreasing loss. Good. Let me also consider making the curriculum reach M=10 a bit earlier and spend more epochs there, since that's where the rollout robustness is built. Actually the current schedule spends the last 28% at M=10 (epochs ~58-80 → 22 epochs). That's good. Let me also reconsider: should validation use EMA or raw? I track both and keep the best. Good. Let me launch the main run.
The pipeline works and already approaches the baseline in just 6 epochs. Let me launch the full 80-epoch primary run in the background and monitor it.
bash
cd /app && nohup env EPOCHS=80 TAG=main SAVE_PATH=/app/outputs/model_main.pt python3 train_improved.py > /app/outputs/log_main.txt 2>&1 &
echo "launched PID $!"; sleep 60; echo "---- progress ----"; tail -5 /app/outputs/log_main.txt
output
launched PID 206
---- progress ----
[main] feat_mean=-0.00000 feat_std=1.15997 device=cuda
The first validation only starts at epoch >= 0.3*80 = 24. So no log lines until epoch 25ish. Let me wait more. Meanwhile, let me think about other experiments and prepare them. Actually, the validation printout only happens at ep >= 24 and (ep%3==0 or ep >= 74). So first print around ep 24 or 25. Let me wait. Each epoch in early phase (M=1,2) is fast. Let me poll again. While waiting, let me think about the pushforward variant and the noise variant. Let me reconsider the pushforward implementation , currently it only computes loss on the last step, which wastes the intermediate ground truth. A better pushforward: unroll with no-grad for a random number r in [0, M-1] steps, then do a 1-step grad update against the ground truth at that position. But my implementation is fixed to last step. Actually, the more standard and effective approach that I've already got (full BPTT with curriculum) is performing well. Let me focus on tuning that rather than pushforward. Let me also consider a potential improvement: since the dynamics are smooth and nearly low-dimensional, maybe training the model to predict the residual (delta = next - last) instead of the absolute next frame could help, because the frame-to-frame change is small (~3.4%). Predicting a residual is often easier and more accurate for small time steps. However, I cannot change the architecture or its output meaning easily , but I CAN change what the target is and reconstruct. Wait, the model is used by the grader directly: grader calls model(window) and expects the next frame (in normalized space, then denormalized with feat_mean/feat_std). So the model MUST output the next frame in normalized units. I can't make it output a residual unless I bake the "add last frame" into... no, the architecture is fixed and the grader uses it as-is. Hmm, wait. Let me reconsider. The grader loads state_dict into build_model(config) and calls it autoregressively. So model(window_normalized) must return next_frame_normalized. I cannot change that contract. So residual prediction would require the model to internally add the last frame, which the fixed architecture doesn't do. So I can't do residual prediction. Fine. But actually , could I train the model such that its output = normalized next frame, while internally the training uses a residual parameterization? No, because the mapping is fixed: whatever the network outputs IS the prediction. I could only change this if I wrapped it, but the grader uses build_model + state_dict, no wrapper. So no. OK so the model predicts the full next frame. That's fine; single-step error is already tiny. Let me keep focusing on rollout training quality. Let me poll the run.
The first rollout-validation prints around epoch 24 (I gated early-epoch eval to save time). Let me wait and monitor progress.
bash
cd /app && sleep 150; tail -8 /app/outputs/log_main.txt
output
[main] feat_mean=-0.00000 feat_std=1.15997 device=cuda
[main] ep=25/80 M=4 loss=1.0755e-02 best_rl2=0.01093(final 0.01806 ema@25) lr=1.24e-03 t=87s
[main] ep=28/80 M=4 loss=1.7491e-02 best_rl2=0.01093(final 0.01806 ema@25) lr=1.16e-03 t=107s
[main] ep=31/80 M=4 loss=9.3020e-03 best_rl2=0.01064(final 0.01691 ema@31) lr=1.08e-03 t=124s
[main] ep=34/80 M=6 loss=1.5237e-02 best_rl2=0.00922(final 0.01454 ema@34) lr=1.00e-03 t=145s
[main] ep=37/80 M=6 loss=1.1355e-02 best_rl2=0.00814(final 0.01275 ema@37) lr=9.15e-04 t=167s
[main] ep=40/80 M=6 loss=7.1439e-03 best_rl2=0.00730(final 0.01141 ema@40) lr=8.27e-04 t=190s
[main] ep=43/80 M=6 loss=9.8400e-03 best_rl2=0.00612(final 0.00958 ema@43) lr=7.38e-04 t=213s
Good progress! At epoch 43, best_rl2=0.00612 (final 0.00958), already significantly better than the baseline (0.0093 mean / 0.0176 final). And it's still improving as M increases and LR decays. Let me wait for it to finish. The larger M epochs (8, 10) are ahead, which should further improve rollout robustness. Let me wait for completion.
Excellent progress , by epoch 43 it's at **0.0061 mean / 0.0096 final**, already well below the baseline's 0.0093/0.0176. The harder curriculum stages (M=8,10) are still ahead. Let me wait for completion.
bash
cd /app && sleep 180; tail -10 /app/outputs/log_main.txt
output
[main] ep=37/80 M=6 loss=1.1355e-02 best_rl2=0.00814(final 0.01275 ema@37) lr=9.15e-04 t=167s
[main] ep=40/80 M=6 loss=7.1439e-03 best_rl2=0.00730(final 0.01141 ema@40) lr=8.27e-04 t=190s
[main] ep=43/80 M=6 loss=9.8400e-03 best_rl2=0.00612(final 0.00958 ema@43) lr=7.38e-04 t=213s
[main] ep=46/80 M=8 loss=1.2072e-02 best_rl2=0.00512(final 0.00805 ema@46) lr=6.50e-04 t=237s
[main] ep=49/80 M=8 loss=7.0779e-03 best_rl2=0.00500(final 0.00786 ema@49) lr=5.65e-04 t=262s
[main] ep=52/80 M=8 loss=8.4958e-03 best_rl2=0.00432(final 0.00675 ema@52) lr=4.81e-04 t=286s
[main] ep=55/80 M=8 loss=3.9573e-03 best_rl2=0.00367(final 0.00574 ema@55) lr=4.02e-04 t=309s
[main] ep=58/80 M=10 loss=4.6450e-03 best_rl2=0.00314(final 0.00493 ema@58) lr=3.28e-04 t=331s
[main] ep=61/80 M=10 loss=5.3483e-03 best_rl2=0.00274(final 0.00429 ema@61) lr=2.60e-04 t=356s
[main] ep=64/80 M=10 loss=4.2694e-03 best_rl2=0.00251(final 0.00391 ema@64) lr=1.99e-04 t=382s
At epoch 64, best_rl2=0.00251 (final 0.00391), still dropping steadily as LR anneals. This is ~3.7x better than baseline already. Let me wait for the final epochs.
Steady improvement , epoch 64 at **0.0025 mean / 0.0039 final** (~3.7× better than baseline). Let me let it finish the final annealing epochs.
bash
cd /app && sleep 130; tail -6 /app/outputs/log_main.txt; echo "--- still running? ---"; pgrep -f train_improved.py || echo "DONE"
output
[main] ep=73/80 M=10 loss=1.6914e-03 best_rl2=0.00198(final 0.00310 ema@73) lr=6.12e-05 t=461s
[main] ep=75/80 M=10 loss=1.4519e-03 best_rl2=0.00189(final 0.00295 raw@75) lr=4.08e-05 t=482s
[main] ep=76/80 M=10 loss=1.2293e-03 best_rl2=0.00174(final 0.00277 raw@76) lr=3.21e-05 t=494s
[main] ep=77/80 M=10 loss=1.1946e-03 best_rl2=0.00174(final 0.00277 raw@76) lr=2.44e-05 t=506s
[main] ep=78/80 M=10 loss=1.1336e-03 best_rl2=0.00167(final 0.00263 raw@78) lr=1.78e-05 t=519s
[main] ep=79/80 M=10 loss=1.1123e-03 best_rl2=0.00167(final 0.00263 raw@78) lr=1.22e-05 t=532s
--- still running? ---
208
bash
cd /app && sleep 20; tail -2 /app/outputs/log_main.txt; pgrep -f train_improved.py >/dev/null && echo RUNNING || echo DONE
output
[main] ep=80/80 M=10 loss=1.0947e-03 best_rl2=0.00162(final 0.00254 raw@80) lr=7.61e-06 t=544s
[main] SAVED /app/outputs/model_main.pt best_val_rollout_rel_l2=0.00162 final=0.00254 (raw@ep80)
DONE
The main run finished with best_val_rollout_rel_l2=0.00162 (final 0.00254) , about 5.7x better than the baseline's 0.0093 (mean) / 0.0176 (final). Let me verify this with my independent rollout_eval harness on both val and public_test, and compare against baseline directly to confirm the improvement is real and consistent. Note: the selected checkpoint was "raw@ep80". Interesting that raw beat EMA at the end , because LR annealed to near zero, the raw weights converged to a good point and EMA lags. The best was taken across both each eval. Good. Let me run the independent evaluation on val and public_test.
The main run finished at **0.00162 mean / 0.00254 final** on val , about **5.7× better** than the baseline. Let me independently verify with my eval harness on both `val` and the held-out `public_test`, comparing against the baseline.
bash
cd /app && for split in val public_test; do
echo "######## $split ########"
echo "-- baseline --"; python3 rollout_eval.py outputs/baseline_10ep.pt $split | sed -n '2,4p'
echo "-- main --";     python3 rollout_eval.py outputs/model_main.pt   $split | sed -n '2,4p'
done
output
######## val ########
-- baseline --
start=4  : mean_rl2=0.0099 final=0.0192 rmse=0.0122
all starts(77): mean_rl2=0.0093 final=0.0176 rmse=0.0108
per-step rl2 [1,2,3,5,10,15,20]: [0.0026, 0.0031, 0.0035, 0.005, 0.0085, 0.0127, 0.0176]
-- main --
start=4  : mean_rl2=0.0018 final=0.0026 rmse=0.0023
all starts(77): mean_rl2=0.0016 final=0.0025 rmse=0.0019
per-step rl2 [1,2,3,5,10,15,20]: [0.0009, 0.0007, 0.001, 0.0012, 0.0014, 0.0021, 0.0025]
######## public_test ########
-- baseline --
start=4  : mean_rl2=0.0082 final=0.0149 rmse=0.0105
all starts(77): mean_rl2=0.0076 final=0.0145 rmse=0.0092
per-step rl2 [1,2,3,5,10,15,20]: [0.0023, 0.0027, 0.003, 0.0042, 0.0069, 0.0103, 0.0145]
-- main --
start=4  : mean_rl2=0.0016 final=0.0023 rmse=0.0021
all starts(77): mean_rl2=0.0013 final=0.0019 rmse=0.0016
per-step rl2 [1,2,3,5,10,15,20]: [0.0007, 0.0005, 0.0008, 0.0009, 0.0011, 0.0016, 0.0019]
The improvement is consistent and large across both val and public_test: - val: baseline mean 0.0093 → main 0.0016 (5.8x better); final 0.0176 → 0.0025 (7x better) - public_test: baseline mean 0.0076 → main 0.0013 (5.8x better); final 0.0145 → 0.0019 (7.6x better) Crucially, look at the per-step curve for main: step 1 rel L2 = 0.0009, and step 20 = 0.0025. The error barely grows over the rollout! Compare baseline: step 1 = 0.0026 → step 20 = 0.0176 (grows 6.8x). The multi-step training dramatically flattened the error-growth curve. This confirms the rollout-aware training is doing exactly what we want: suppressing compounding error. Now, the public_test generalization matches val well, so no overfitting concern. Now let me see if I can squeeze more. Let me consider ablations/variants: 1. Does augmentation help? Let me test AUG=0 to confirm aug contributes. 2. Would training the rollout to the full 20 steps (MAX_M higher, e.g., 12-15) help the final-step error further? But eval is 20 steps; training at M=10 already generalizes to 20 with nearly flat error. Pushing M higher might help or might destabilize / overfit. 3. Longer training or different LR. But I should be careful: the improvements are already huge (5.8x). The risk is over-engineering. Let me do a couple of targeted ablations to (a) confirm robustness and (b) see if a small tweak helps, then finalize. However, I should be mindful of the token budget. Let me run a couple of focused experiments in parallel-ish (sequentially) but with fewer epochs to compare settings quickly, OR just validate the key design choices. Actually, the most valuable check: confirm that the result is stable/reproducible and not a fluke of seed, and confirm augmentation helps generalization to public_test. Let me run an ablation without augmentation (AUG=0) for 80 epochs and compare public_test. Also try MAX_M=15 to see if longer rollout training helps the later steps. But each 80-epoch run is ~9 min. Let me run two variants. To save time, let me run them at 60 epochs which is enough to see the trend, OR run the two most informative ones. Actually, let me think about what matters for the final grade. The grader does 20-step rollout. My main model already has nearly flat error growth to step 20 (0.0009 → 0.0025). The biggest lever left might be training directly at longer horizons to match the 20-step eval better, OR it might already be near the achievable floor given single-step noise. Let me check: what's the single-step error floor? In the main model, step-1 rel L2 is 0.0009. That's extremely low. The data itself , is it deterministic enough? The frames come from a numerical integrator, so it's deterministic. The model captures it to 0.0009 relative error at step 1. Let me consider whether pushing MAX_M to, say, 16 or 20 would reduce the later-step error. Since eval is exactly 20 steps, training with M=20 would directly optimize the eval horizon. But full BPTT over 20 steps is more expensive and potentially less stable. Let me test a variant with MAX_M=20 and a schedule that reaches it. Actually, let me also reconsider: maybe I can improve by allocating more epochs to the high-M phase and fewer to low-M. But the current schedule works great. Let me run two experiments to potentially improve further and to provide ablation evidence: - Variant A: MAX_M=16, EPOCHS=90 (reach longer horizon). - Variant B: AUG=0 ablation (to demonstrate augmentation value), EPOCHS=80. Let me run Variant A first since it might improve the final model. I'll run in background. Actually, let me be even more strategic. Let me run a longer/higher-M run that also extends training at the top horizon, and simultaneously do the no-aug ablation. Run sequentially to avoid GPU contention (though H100 could handle both, contention may slow both and muddy timing; correctness is fine). I'll run them in background concurrently since the model is tiny and GPU is 80GB , two runs is fine. Let me launch both. Let me s …[truncated]
This is a consistent, large improvement on both val and (held-out) public_test: **~5.8× lower mean rel L2 and ~7× lower final-step error**. Critically, the per-step error is now nearly flat (step 1: 0.0009 → step 20: 0.0025) versus the baseline's steep growth (0.0026 → 0.0176) , confirming the rollout-aware training is suppressing error compounding exactly as intended. Now let me run two focused experiments: (A) extend the curriculum to a longer horizon (M=16) to see if it further helps the late-rollout steps, and (B) an augmentation ablation to quantify its contribution. First I'll make the curriculum's top stage smoother.
str_replace_based_edit_tool
command: str_replace
path: /app/train_improved.py
old_str:     if frac < 0.55:   return 6
    if frac < 0.72:   return 8
    return MAX_M
new_str:     if frac < 0.55:   return 6
    if frac < 0.72:   return 8
    if frac < 0.85:   return min(MAX_M, 10)
    return MAX_M
output
The file /app/train_improved.py has been edited successfully.
bash
cd /app && nohup env EPOCHS=90 MAX_M=16 TAG=longM SAVE_PATH=/app/outputs/model_longM.pt python3 train_improved.py > /app/outputs/log_longM.txt 2>&1 &
echo "longM PID $!"
nohup env EPOCHS=80 MAX_M=10 AUG=0 TAG=noaug SAVE_PATH=/app/outputs/model_noaug.pt python3 train_improved.py > /app/outputs/log_noaug.txt 2>&1 &
echo "noaug PID $!"
sleep 5; echo "both launched"; nvidia-smi --query-gpu=memory.used,utilization.gpu --format=csv,noheader
output
longM PID 308
noaug PID 309
both launched
15470 MiB, 99 %
Both are running concurrently on the GPU (15GB used, 99% util). They'll take a bit longer due to sharing but that's fine. Let me wait. Each is ~80-90 epochs. With two concurrent, maybe ~12-15 min total. While waiting, let me reconsider the output contract and make sure my saved checkpoint is exactly compatible. The contract: model.pt must be loadable with torch.load(..., weights_only=True) containing: - state_dict matching build_model(task_config) - feat_mean, feat_std as float scalars My save does: torch.save({"state_dict": best["state"], "feat_mean": feat_mean, "feat_std": feat_std}, SAVE_PATH). best["state"] is a deepcopy of model.state_dict() (on GPU). When saved and reloaded, the tensors will be on GPU originally but torch.save stores device; torch.load with map_location... the grader might load with weights_only=True and then do model.load_state_dict. Let me make sure state_dict tensors are on CPU to be safe, and feat_mean/feat_std are Python floats. feat_mean and feat_std are Python floats (from compute_standardization which returns float()). Good. The state dict from a CUDA model contains CUDA tensors. When saved, torch.save serializes them with device info. torch.load(weights_only=True) without map_location will try to put them on CUDA. The grader loads on whatever device; to be safe I should save CPU tensors. Let me verify my checkpoint loads correctly with weights_only=True and also move state to CPU before saving to be safe. Also, there's the "_grid" buffer which is persistent=False, so it's NOT in state_dict. build_model recreates it. Good , load_state_dict won't complain about missing _grid because it's non-persistent (not expected in state_dict). Let me verify load_state_dict with strict=True works on my checkpoint. Let me verify the current main checkpoint loads cleanly and check device of tensors.
Both runs are training concurrently on the GPU. While they run, let me verify my saved checkpoint **exactly** satisfies the output contract , loadable with `weights_only=True`, `state_dict` matching `build_model(task_config)` under `strict=True`, and scalar `feat_mean/feat_std`.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
cfg = json.load(open('task_config.json'))
ck = torch.load('outputs/model_main.pt', weights_only=True)
print('top-level keys:', list(ck.keys()))
print('feat_mean type/val:', type(ck['feat_mean']).__name__, ck['feat_mean'])
print('feat_std  type/val:', type(ck['feat_std']).__name__, ck['feat_std'])
devs = set(str(v.device) for v in ck['state_dict'].values())
print('state_dict tensor devices:', devs)
m = build_model(cfg)
ret = m.load_state_dict(ck['state_dict'], strict=True)
print('load_state_dict strict=True OK:', ret)
# confirm a forward pass on cpu
import torch
x = torch.randn(2,4,128)
print('forward output shape:', tuple(m(x).shape))
"
output
top-level keys: ['state_dict', 'feat_mean', 'feat_std']
feat_mean type/val: float -3.819819571759808e-09
feat_std  type/val: float 1.1599736213684082
state_dict tensor devices: {'cuda:0'}
load_state_dict strict=True OK: <All keys matched successfully>
forward output shape: (2, 1, 128)
The checkpoint loads correctly with strict=True and weights_only=True. But the state_dict tensors are on cuda:0. The grader likely handles this (torch.load with weights_only=True will load to CUDA if available; if grader runs on CPU it would need map_location). To be maximally safe and portable, I should save the state_dict with CPU tensors. Let me update the training script to move best state to CPU before saving, and also re-save the main model to CPU now as a safety measure. Let me update the save logic in train_improved.py to move tensors to CPU. And I'll create the final model.pt from the best checkpoint at the end, ensuring CPU tensors. Actually, weights_only=True loading: if the grader does torch.load(path, weights_only=True) on a CUDA-available machine, cuda tensors load fine. If on CPU-only, it errors without map_location. The task says the grader rolls the model; it likely has GPU. But to be safe, CPU tensors are universally loadable. Let me make the final save use CPU tensors. Let me update the script's save section and also plan to re-save whichever model wins to CPU. Let me edit train_improved.py to save CPU tensors.
The checkpoint loads with `strict=True` under `weights_only=True`. One robustness improvement: the tensors are on `cuda:0`. To make the checkpoint portable (loadable even on a CPU-only grader without `map_location`), I'll store CPU tensors. Let me fix the save logic and store best states on CPU.
str_replace_based_edit_tool
command: str_replace
path: /app/train_improved.py
old_str:             if sc < best["score"]:
                best = {"score": sc, "final": r["final_step_rel_l2"], "which": name, "epoch": ep,
                        "state": copy.deepcopy(mdl.state_dict())}
new_str:             if sc < best["score"]:
                cpu_state = {k: v.detach().cpu().clone() for k, v in mdl.state_dict().items()}
                best = {"score": sc, "final": r["final_step_rel_l2"], "which": name, "epoch": ep,
                        "state": cpu_state}
output
The file /app/train_improved.py has been edited successfully.
bash
cd /app && sleep 210; echo "=== longM ==="; tail -3 /app/outputs/log_longM.txt; echo "=== noaug ==="; tail -3 /app/outputs/log_noaug.txt
output
=== longM ===
[longM] ep=37/90 M=6 loss=9.4912e-03 best_rl2=0.00789(final 0.01227 ema@37) lr=1.03e-03 t=153s
[longM] ep=40/90 M=6 loss=1.6992e-02 best_rl2=0.00789(final 0.01227 ema@37) lr=9.57e-04 t=181s
[longM] ep=43/90 M=6 loss=7.4957e-03 best_rl2=0.00789(final 0.01227 ema@37) lr=8.79e-04 t=209s
=== noaug ===
[noaug] ep=37/80 M=6 loss=8.0489e-03 best_rl2=0.00949(final 0.01496 ema@37) lr=9.15e-04 t=169s
[noaug] ep=40/80 M=6 loss=1.0435e-02 best_rl2=0.00749(final 0.01170 ema@40) lr=8.27e-04 t=196s
[noaug] ep=43/80 M=6 loss=6.4300e-03 best_rl2=0.00612(final 0.00951 ema@43) lr=7.38e-04 t=224s
They're progressing, slightly slower due to sharing. Let me wait more. The longM run has 90 epochs and reaches M=16, so it'll take longer. Let me wait. At epoch 43, noaug is at 0.00612 (same as main was at ep43 with aug: 0.00612). Interesting , at this stage aug doesn't show a difference yet on val. The aug benefit may show more in generalization to public_test, or may be marginal on this val set. Let me wait for final numbers. longM at ep43 is at 0.00789, a bit behind main's 0.00612 at ep43 , but longM has a different schedule (90 epochs, so frac is different; at ep43/90 frac=0.48 → M=6, whereas main ep43/80 frac=0.54 → M=6). Similar. The longM eval cadence differs. Let me just wait for completion. Let me wait ~4 more minutes.
Both progressing well. Let me wait for them to complete (longM has 90 epochs reaching M=16, so it's the longer one).
bash
cd /app && sleep 220; echo "=== longM ==="; tail -3 /app/outputs/log_longM.txt; echo "=== noaug ==="; tail -3 /app/outputs/log_noaug.txt; echo "--- running ---"; pgrep -f train_improved.py || echo NONE
output
=== longM ===
[longM] ep=61/90 M=8 loss=6.5234e-03 best_rl2=0.00348(final 0.00528 ema@61) lr=4.22e-04 t=376s
[longM] ep=64/90 M=8 loss=3.2117e-03 best_rl2=0.00317(final 0.00484 ema@64) lr=3.54e-04 t=406s
[longM] ep=67/90 M=10 loss=3.3459e-03 best_rl2=0.00281(final 0.00432 ema@67) lr=2.92e-04 t=441s
=== noaug ===
[noaug] ep=58/80 M=10 loss=8.1025e-03 best_rl2=0.00321(final 0.00494 ema@58) lr=3.28e-04 t=365s
[noaug] ep=61/80 M=10 loss=5.4871e-03 best_rl2=0.00284(final 0.00438 ema@61) lr=2.60e-04 t=395s
[noaug] ep=64/80 M=10 loss=3.1952e-03 best_rl2=0.00256(final 0.00396 ema@64) lr=1.99e-04 t=431s
--- running ---
309
311
Both still running. noaug at ep64: 0.00256 (vs main aug at ep64: 0.00251 , essentially identical). So on val, augmentation doesn't seem to make a big difference. But let me check generalization on public_test at the end, which is the better test of whether aug helps. longM at ep67: 0.00281, with M reaching 10 now and 16 later. Let me wait for both to finish. The noaug (80 epochs) should finish first.
bash
cd /app && sleep 150; echo "=== noaug tail ==="; tail -2 /app/outputs/log_noaug.txt; echo "=== longM tail ==="; tail -2 /app/outputs/log_longM.txt; pgrep -f train_improved.py || echo NONE
output
=== noaug tail ===
[noaug] ep=77/80 M=10 loss=1.1710e-03 best_rl2=0.00193(final 0.00289 raw@77) lr=2.44e-05 t=587s
[noaug] ep=78/80 M=10 loss=1.1366e-03 best_rl2=0.00178(final 0.00276 raw@78) lr=1.78e-05 t=602s
=== longM tail ===
[longM] ep=76/90 M=10 loss=2.4086e-03 best_rl2=0.00216(final 0.00333 ema@76) lr=1.36e-04 t=543s
[longM] ep=79/90 M=16 loss=3.6883e-03 best_rl2=0.00203(final 0.00311 ema@79) lr=9.82e-05 t=583s
309
311
noaug is almost done (ep78/80), best 0.00178 (vs main with aug 0.00162). So aug helped slightly on val (0.00162 vs 0.00178). longM at ep79, M=16 now, best 0.00203 , but longM still has epochs left (up to 90) at M=16. The M=16 phase shows loss=3.7e-3 which is higher (harder). Let me wait for both to finish. Let me wait a bit more for both to complete.
bash
cd /app && sleep 120; echo "=== noaug ==="; grep SAVED /app/outputs/log_noaug.txt || tail -1 /app/outputs/log_noaug.txt; echo "=== longM ==="; grep SAVED /app/outputs/log_longM.txt || tail -2 /app/outputs/log_longM.txt; pgrep -f train_improved.py || echo ALL_DONE
output
=== noaug ===
[noaug] SAVED /app/outputs/model_noaug.pt best_val_rollout_rel_l2=0.00174 final=0.00270 (raw@ep79)
=== longM ===
[longM] SAVED /app/outputs/model_longM.pt best_val_rollout_rel_l2=0.00154 final=0.00229 (raw@ep90)
ALL_DONE
Both finished: - main (aug, M=10, 80 ep): val best 0.00162, final 0.00254 - noaug (M=10, 80 ep): val best 0.00174, final 0.00270 → aug helps (0.00162 < 0.00174) - longM (aug, M=16, 90 ep): val best 0.00154, final 0.00229 → slightly better than main So longM is the best on val so far. Let me independently evaluate all three on both val and public_test to pick the best generalizing model. The independent eval averages over all 77 start positions, which is more robust than the single training-time val metric.
All three finished. Summary of training-time val scores: - **main** (aug, M=10): 0.00162 - **noaug** (M=10): 0.00174 → augmentation helps - **longM** (aug, M=16, 90ep): 0.00154 → best Let me independently evaluate all three (plus baseline) on both val and the held-out public_test to choose the best-generalizing model robustly.
bash
cd /app && for ck in baseline_10ep model_noaug model_main model_longM; do
  echo "### $ck ###"
  for split in val public_test; do
    line=$(python3 rollout_eval.py outputs/$ck.pt $split | sed -n '3p')
    echo "  $split  $line"
  done
done
output
### baseline_10ep ###
  val  all starts(77): mean_rl2=0.0093 final=0.0176 rmse=0.0108
  public_test  all starts(77): mean_rl2=0.0076 final=0.0145 rmse=0.0092
### model_noaug ###
  val  all starts(77): mean_rl2=0.0017 final=0.0027 rmse=0.0021
  public_test  all starts(77): mean_rl2=0.0016 final=0.0025 rmse=0.0020
### model_main ###
  val  all starts(77): mean_rl2=0.0016 final=0.0025 rmse=0.0019
  public_test  all starts(77): mean_rl2=0.0013 final=0.0019 rmse=0.0016
### model_longM ###
  val  all starts(77): mean_rl2=0.0015 final=0.0023 rmse=0.0018
  public_test  all starts(77): mean_rl2=0.0012 final=0.0018 rmse=0.0015
Results (all-starts, the robust metric): | model | val mean | val final | public mean | public final | |---|---|---|---|---| | baseline | 0.0093 | 0.0176 | 0.0076 | 0.0145 | | noaug | 0.0017 | 0.0027 | 0.0016 | 0.0025 | | main (aug) | 0.0016 | 0.0025 | 0.0013 | 0.0019 | | longM (aug, M16) | 0.0015 | 0.0023 | 0.0012 | 0.0018 | So: - Augmentation helps generalization: main beats noaug especially on public_test (0.0013 vs 0.0016 mean, 0.0019 vs 0.0025 final). - longM (M=16) is the best overall: public_test mean 0.0012, final 0.0018. longM is the best on both val and public_test. The gains are consistent. longM is ~6x better than baseline on public_test mean and ~8x on final. Let me decide the final model. longM is clearly the best and generalizes well. But before finalizing, let me consider: is there value in pushing even further (e.g., M=20 to exactly match eval horizon, or an ensemble)? The grader uses a single model (build_model + state_dict), so no ensemble. Could M=20 help more? The trend from M=10 (main) → M=16 (longM) improved final-step from 0.0019→0.0018 on public_test , marginal. Diminishing returns. Pushing to M=20 might help the final steps slightly but risks instability and longer training. Given the strong results and diminishing returns, I think longM is a great final choice. However, let me also double check robustness: the grader might start the rollout from a specific frame (likely the first 4 frames of each test trajectory, i.e., start=4) and roll 20 steps. My "all starts" averaging is a superset. Let me also check the start=4 specific numbers for longM, and verify stability at start=4 for public_test. Let me also sanity-check that the model is stable over LONGER rollouts than 20 (e.g., 40-76 steps) , this indicates it won't blow up and is genuinely stable, which is reassuring even though eval is 20. Let me verify longM at start=4 and test a long 50-step rollout for stability. Also, I realize I should consider whether to train a final model with an even better configuration combining the best of everything, possibly with a different seed, and maybe averaging. But I think longM is solid. Let me consider one more improvement idea: a longer high-M phase. longM spent epochs 77-90 (14 epochs) ramping 10→16. The M=16 phase loss was still a bit high (3.7e-3). Maybe a dedicated run that reaches M=20 with more epochs at the top could help. But the marginal gain from M10→M16 was tiny. I'll not chase it further; risk/reward is poor and I want to preserve token budget. Let me do a robustness check on longM: start=4 eval, and a 50-step rollout stability check. Then finalize longM as /app/outputs/model.pt. Actually, let me reconsider one thing: model selection used the val rollout during training, and I'm now also using val/public_test to pick among 3 models. public_test is described as "public_test" , it's available to me, so using it for selection is fine (it's not the hidden grader set). The hidden grader likely uses a separate held-out set. Since val and public_test agree that longM is best, and the improvements are consistent and large, longM should generalize to the hidden set too. Let me do the robustness checks.
Clear ranking (all-starts metric): **longM** is best on both val and public_test, and **augmentation measurably improves generalization** (main beats noaug, especially on public_test). Summary: | model | val mean / final | public_test mean / final | |---|---|---| | baseline | 0.0093 / 0.0176 | 0.0076 / 0.0145 | | noaug | 0.0017 / 0.0027 | 0.0016 / 0.0025 | | main (aug, M10) | 0.0016 / 0.0025 | 0.0013 / 0.0019 | | **longM (aug, M16)** | **0.0015 / 0.0023** | **0.0012 / 0.0018** | Before finalizing, let me verify longM is robust: check the grader-like `start=4` case and confirm it stays stable well beyond 20 steps (no blow-up at longer horizons).
bash
cd /app && python3 -c "
import json, torch
from rollout_eval import load_model, rollout_eval
cfg = json.load(open('task_config.json')); dev='cuda'
model, fm, fs = load_model('outputs/model_longM.pt', cfg, dev)
for split in ['val','public_test']:
    traj = torch.load(f'data/{split}/trajectories.pt', weights_only=True)['trajectories'].float()
    r4 = rollout_eval(model, fm, fs, traj, dev, horizon=20, starts=[4])
    r50 = rollout_eval(model, fm, fs, traj, dev, horizon=50, starts=[4])
    print(f'{split}: start=4 20-step mean={r4[\"mean_rollout_rel_l2\"]:.4f} final={r4[\"final_step_rel_l2\"]:.4f} | 50-step final={r50[\"final_step_rel_l2\"]:.4f} (stability)')
"
output
val: start=4 20-step mean=0.0018 final=0.0025 | 50-step final=0.0246 (stability)
public_test: start=4 20-step mean=0.0016 final=0.0021 | 50-step final=0.0207 (stability)
The model is stable: even at 50 steps (way beyond the 20-step eval horizon), the error only grows to ~0.02-0.025, no blow-up. At the graded 20-step horizon from start=4, it's 0.0018 mean / 0.0025 final on val, 0.0016/0.0021 on public_test. longM is clearly the best and robust. Let me finalize it as /app/outputs/model.pt. Let me also reconsider: should I try to squeeze a bit more with a final polished run? The improvements from main→longM were small. I have decent token budget left (~148k). Let me consider one more experiment that could meaningfully help: a run reaching M=20 (exact eval horizon) with more total epochs and a longer top-horizon phase, plus maybe slightly higher EMA and a bit more epochs. If it beats longM on both val and public_test, I use it; otherwise I keep longM. Actually, let me think about the risk. Training with full BPTT at M=20 over ~100 epochs is more expensive (~15-20 min) and the marginal gains are likely small. But since it directly matches the eval horizon, it's the most principled. Let me do ONE more run: EPOCHS=110, MAX_M=20, with a schedule that spends a good chunk at M=20. I'll also bump the schedule so it reaches higher M. Let me adjust the curriculum to add M=12,16 stages before 20. Let me refine the curriculum to be a smooth ramp to MAX_M regardless of its value, so M=20 gets proper intermediate stages. I'll rewrite rollout_len_for_epoch to ramp through a list of fractions up to MAX_M. Let me make the schedule adaptive: define stage boundaries and values that scale with MAX_M. I'll rewrite to: stages at fracs [0.12,0.25,0.40,0.55,0.70,0.82,0.92] with M values [1,2,4,6,8, then ramp]. Simpler: build a generic ramp. Let me just write: ``` def rollout_len_for_epoch(ep): frac = ep/max(1,EPOCHS-1) # warmup single-step if frac < 0.12: return 1 # ramp from 2 to MAX_M across frac in [0.12, 0.80], then hold MAX_M if frac >= 0.80: return MAX_M r = (frac - 0.12)/(0.80-0.12) # 0..1 m = 2 + r*(MAX_M-2) # round to nearest even-ish integer return int(round(m)) ``` This gives a smooth ramp to MAX_M by frac 0.80, then holds MAX_M for the last 20% of epochs. For MAX_M=20, EPOCHS=110: last 22 epochs at M=20. For MAX_M=16, it'd differ from before but that's fine. But wait , changing the schedule will also change behavior for longM reproduction. That's fine; I'm doing a new run. But I should keep longM's checkpoint as the current best fallback. Actually, I worry about full BPTT at M=20 stability and memory. Memory: B=128, 20 steps, each storing activations for a 4-layer FNO width 32 on length 128. That's tiny (~ KBs per layer). Fine. Stability: with curriculum and grad clip, should be OK. Let me also reconsider LR for longer training: keep 1.5e-3. Let me launch this final run (call it "bestM20") and compare. Meanwhile set longM as the provisional final model so I always have a valid /app/outputs/model.pt. Let me first copy longM to the official output path as a safe checkpoint.
longM is stable even at 50 steps (error only ~0.02, no blow-up) and excellent at the graded 20-step horizon. I'll set it as the provisional official checkpoint now so a valid deliverable always exists, then attempt one more run that trains at the exact eval horizon (M=20) to see if it improves further.
bash
cd /app && cp outputs/model_longM.pt outputs/model.pt && python3 -c "
import torch,json; from candidate_model import build_model
cfg=json.load(open('task_config.json')); ck=torch.load('outputs/model.pt',weights_only=True)
build_model(cfg).load_state_dict(ck['state_dict'],strict=True)
print('provisional /app/outputs/model.pt OK; keys', list(ck.keys()), 'devices', set(str(v.device) for v in ck['state_dict'].values()))
"
output
provisional /app/outputs/model.pt OK; keys ['state_dict', 'feat_mean', 'feat_std'] devices {'cuda:0'}
The provisional model.pt loads fine. Note its tensors are on cuda:0 (because longM was trained before my CPU-save edit took effect , wait, I edited the script before launching longM and noaug? Let me check. I made the CPU-save edit AFTER launching longM and noaug. Let me check: I launched longM and noaug, then edited the save logic. So longM was saved with the OLD logic (GPU tensors). That's why model.pt has cuda:0 tensors. I should re-save model.pt with CPU tensors for portability. Let me just convert the current model.pt to CPU tensors regardless of which model I finalize. I'll do that at the very end for whatever final model I choose. Now let me set up and launch the M=20 run with the improved smooth curriculum. Let me edit rollout_len_for_epoch to a generic ramp. Actually, I need to be careful: editing the function affects reproducibility but I'm launching a fresh run so it's fine. Let me update it.
The provisional `model.pt` is valid (I'll convert its tensors to CPU at the very end for portability). Now let me generalize the curriculum into a smooth ramp so it works well for any `MAX_M`, then launch a run that trains at the exact eval horizon (M=20).
str_replace_based_edit_tool
command: str_replace
path: /app/train_improved.py
old_str: def rollout_len_for_epoch(ep):
    # gradually grow the training rollout horizon
    frac = ep / max(1, EPOCHS - 1)
    if frac < 0.12:   return 1
    if frac < 0.25:   return 2
    if frac < 0.40:   return 4
    if frac < 0.55:   return 6
    if frac < 0.72:   return 8
    if frac < 0.85:   return min(MAX_M, 10)
    return MAX_M
new_str: CURRICULUM = os.environ.get("CURRICULUM", "stager")  # stager | ramp
def rollout_len_for_epoch(ep):
    # gradually grow the training rollout horizon
    frac = ep / max(1, EPOCHS - 1)
    if CURRICULUM == "ramp":
        # single-step warmup, smooth ramp 2..MAX_M by frac=0.80, then hold MAX_M
        if frac < 0.12:  return 1
        if frac >= 0.80: return MAX_M
        r = (frac - 0.12) / (0.80 - 0.12)
        return int(round(2 + r * (MAX_M - 2)))
    if frac < 0.12:   return 1
    if frac < 0.25:   return 2
    if frac < 0.40:   return 4
    if frac < 0.55:   return 6
    if frac < 0.72:   return 8
    if frac < 0.85:   return min(MAX_M, 10)
    return MAX_M
output
The file /app/train_improved.py has been edited successfully.
bash
cd /app && EPOCHS=110 python3 -c "
import os
os.environ['EPOCHS']='110'; os.environ['MAX_M']='20'; os.environ['CURRICULUM']='ramp'
# mimic the schedule function
EPOCHS=110; MAX_M=20
def sched(ep):
    frac=ep/(EPOCHS-1)
    if frac<0.12: return 1
    if frac>=0.80: return MAX_M
    r=(frac-0.12)/(0.80-0.12); return int(round(2+r*(MAX_M-2)))
vals=[sched(e) for e in range(EPOCHS)]
from itertools import groupby
print('M schedule (value:count):', [(k,len(list(g))) for k,g in groupby(vals)])
"
output
M schedule (value:count): [(1, 14), (2, 2), (3, 4), (4, 4), (5, 4), (6, 4), (7, 4), (8, 4), (9, 4), (10, 5), (11, 4), (12, 4), (13, 4), (14, 4), (15, 4), (16, 4), (17, 4), (18, 5), (19, 4), (20, 24)]
The ramp schedule looks good: warmup at M=1 for 14 epochs, smooth ramp through M=2..19, then 24 epochs at M=20. This directly optimizes the 20-step eval horizon at the end. Let me launch this run. It'll be the most expensive (110 epochs, high M). With exclusive GPU now, should be ~10-12 min. Let me run it in the background. I'll also bump EMA_DECAY slightly and keep everything else. Actually, keep defaults for clean comparison. Let me launch.
The ramp schedule spends its final 24 epochs training at exactly M=20 (the eval horizon). Let me launch this run with exclusive GPU access.
bash
cd /app && nohup env EPOCHS=110 MAX_M=20 CURRICULUM=ramp TAG=m20 SAVE_PATH=/app/outputs/model_m20.pt python3 train_improved.py > /app/outputs/log_m20.txt 2>&1 &
echo "m20 PID $!"; sleep 90; tail -4 /app/outputs/log_m20.txt
output
m20 PID 520
[m20] feat_mean=-0.00000 feat_std=1.15997 device=cuda
Validation starts at ep >= 0.3*110 = 33. Let me wait. Meanwhile, let me think about whether there's anything else worth doing. One more idea worth testing cheaply: evaluate whether my models are robust to the exact rollout convention the grader uses. The grader "rolls your model autoregressively for 20 steps." The window update: I assumed window = cat([window[:,1:], pred]). That's the standard sliding window. This matches how the dataset is built (window = last k frames). I'm confident. Another consideration: the grader might feed the model the ground-truth first window (frames 0-3) and compare predictions for frames 4-23. My start=4 eval matches that. Good. Let me also think: is there any chance the grader normalizes differently? The contract says model.pt contains feat_mean, feat_std for "input/output standardization". So the grader does: input_norm = (window - feat_mean)/feat_std; pred_norm = model(input_norm); pred = pred_norm*feat_std + feat_mean. That's exactly what I do. Good. Let me wait for the m20 run to produce validation numbers. While waiting, let me reconsider if I should also produce a "polished main" config as a backup in case m20 doesn't improve. I already have longM as the current best fallback (saved as model.pt). Good. Let me wait ~3 min and check m20 progress.
Validation prints start around epoch 33. Let me wait and monitor the M=20 run.
bash
cd /app && sleep 230; tail -5 /app/outputs/log_m20.txt
output
[m20] ep=46/110 M=10 loss=1.2907e-02 best_rl2=0.00914(final 0.01439 ema@46) lr=1.04e-03 t=194s
[m20] ep=49/110 M=10 loss=1.0851e-02 best_rl2=0.00751(final 0.01170 ema@49) lr=9.78e-04 t=224s
[m20] ep=52/110 M=11 loss=1.3534e-02 best_rl2=0.00629(final 0.00984 ema@52) lr=9.19e-04 t=256s
[m20] ep=55/110 M=12 loss=7.3990e-03 best_rl2=0.00567(final 0.00900 ema@55) lr=8.59e-04 t=286s
[m20] ep=58/110 M=13 loss=1.0319e-02 best_rl2=0.00499(final 0.00783 ema@58) lr=7.99e-04 t=317s
At ep58 (M=13), best 0.00499. It's progressing. The high-M phase and LR annealing are ahead. This run has more epochs so by ep110 it should converge well. Let me wait. It's at t=317s for ep58; 110 epochs at increasing M... maybe ~650s total. Let me wait ~5 more min.
bash
cd /app && sleep 240; tail -5 /app/outputs/log_m20.txt
output
[m20] ep=67/110 M=15 loss=7.0879e-03 best_rl2=0.00374(final 0.00584 ema@67) lr=6.22e-04 t=415s
[m20] ep=70/110 M=16 loss=8.5843e-03 best_rl2=0.00340(final 0.00526 ema@70) lr=5.65e-04 t=449s
[m20] ep=73/110 M=16 loss=5.4982e-03 best_rl2=0.00310(final 0.00476 ema@73) lr=5.10e-04 t=481s
[m20] ep=76/110 M=17 loss=6.3494e-03 best_rl2=0.00291(final 0.00446 ema@76) lr=4.57e-04 t=515s
[m20] ep=79/110 M=18 loss=7.4013e-03 best_rl2=0.00261(final 0.00399 ema@79) lr=4.06e-04 t=548s
ep79, M=18, best 0.00261. Still improving, LR still ~4e-4 with 31 epochs to go (all at M=19-20). The final annealing should bring it down further. Let me wait for completion (~31 more epochs, maybe ~5-6 min).
bash
cd /app && sleep 260; tail -5 /app/outputs/log_m20.txt; pgrep -f train_improved.py >/dev/null && echo RUNNING || echo DONE
output
[m20] ep=88/110 M=20 loss=6.2376e-03 best_rl2=0.00220(final 0.00329 ema@88) lr=2.68e-04 t=659s
[m20] ep=91/110 M=20 loss=4.9084e-03 best_rl2=0.00208(final 0.00309 ema@91) lr=2.27e-04 t=701s
[m20] ep=94/110 M=20 loss=5.0036e-03 best_rl2=0.00200(final 0.00295 ema@94) lr=1.89e-04 t=741s
[m20] ep=97/110 M=20 loss=2.7378e-03 best_rl2=0.00190(final 0.00281 ema@97) lr=1.54e-04 t=778s
[m20] ep=100/110 M=20 loss=4.0716e-03 best_rl2=0.00183(final 0.00268 ema@100) lr=1.22e-04 t=817s
RUNNING
ep100, M=20, best 0.00183. Hmm, this is WORSE than longM (0.00154) at this point. The M=20 full-BPTT training has higher per-step loss (harder optimization over 20 steps) and the val metric at ep100 is 0.00183. It may not catch up to longM's 0.00154 in the final 10 epochs. Let me wait for it to finish. Interesting , training at the exact eval horizon (M=20) is actually a HARDER optimization problem and yields worse results than M=16. This is consistent with the literature: very long BPTT horizons can hurt due to optimization difficulty and the model over-focusing on long-horizon at the expense of per-step accuracy. The sweet spot seems to be around M=10-16. Let me wait for m20 to finish and get the final number, then compare. I expect longM to remain the best.
The M=20 run (at ep100: 0.00183) is tracking **worse** than longM (0.00154) , training over the full 20-step BPTT horizon is a harder optimization and over-weights long-horizon at the expense of per-step accuracy. Let me let it finish and confirm.
bash
cd /app && sleep 90; grep SAVED /app/outputs/log_m20.txt || tail -2 /app/outputs/log_m20.txt; pgrep -f train_improved.py >/dev/null && echo RUNNING || echo DONE
output
[m20] ep=106/110 M=20 loss=2.1455e-03 best_rl2=0.00169(final 0.00245 ema@106) lr=6.91e-05 t=897s
[m20] ep=107/110 M=20 loss=1.8759e-03 best_rl2=0.00168(final 0.00243 ema@107) lr=6.16e-05 t=914s
RUNNING
bash
cd /app && sleep 60; grep SAVED /app/outputs/log_m20.txt; pgrep -f train_improved.py >/dev/null && echo RUNNING || echo DONE
output
[m20] SAVED /app/outputs/model_m20.pt best_val_rollout_rel_l2=0.00164 final=0.00235 (ema@ep110)
DONE
m20 finished at val best 0.00164 (final 0.00235), which is worse than longM (0.00154 / 0.00229 on val). Let me confirm with the independent all-starts eval on both splits.
m20 finished at 0.00164 (val) , worse than longM's 0.00154, confirming M=16 is the sweet spot. Let me confirm with the independent all-starts eval on both splits to make the final decision.
bash
cd /app && for ck in model_main model_longM model_m20; do
  v=$(python3 rollout_eval.py outputs/$ck.pt val | sed -n '3p')
  p=$(python3 rollout_eval.py outputs/$ck.pt public_test | sed -n '3p')
  echo "$ck"; echo "   val: $v"; echo "   pub: $p"
done
output
model_main
   val: all starts(77): mean_rl2=0.0016 final=0.0025 rmse=0.0019
   pub: all starts(77): mean_rl2=0.0013 final=0.0019 rmse=0.0016
model_longM
   val: all starts(77): mean_rl2=0.0015 final=0.0023 rmse=0.0018
   pub: all starts(77): mean_rl2=0.0012 final=0.0018 rmse=0.0015
model_m20
   val: all starts(77): mean_rl2=0.0016 final=0.0024 rmse=0.0020
   pub: all starts(77): mean_rl2=0.0013 final=0.0019 rmse=0.0016
Confirmed: **longM (M=16) is the best** on both val and public_test across all metrics: - longM: val 0.0015/0.0023, pub 0.0012/0.0018 - main (M=10): val 0.0016/0.0025, pub 0.0013/0.0019 - m20 (M=20): val 0.0016/0.0024, pub 0.0013/0.0019 So M=16 is the sweet spot. longM wins. The provisional model.pt is already longM. Now let me finalize properly: 1. Re-save model.pt with CPU tensors (for portability) from the longM checkpoint. 2. Verify the final model.pt one more time end-to-end (load with weights_only=True, strict load, run a full 20-step rollout on public_test, print final score). 3. Update train.py so that the "official" training entry point reproduces the winning recipe (the task says "Improve the training recipe" and "Save your checkpoint to /app/outputs/model.pt"). The deliverable is the checkpoint, but it's good practice to make train.py produce the improved model. I'll make /app/train.py run the improved recipe (longM config) so that running `python3 /app/train.py` reproduces the result. I must keep the TASK_EPOCHS_OVERRIDE behavior and ensure it writes /app/outputs/model.pt. Let me think about whether to overwrite train.py. The task explicitly says "Improve the training recipe" and gives local training commands `python3 /app/train.py` and `TASK_EPOCHS_OVERRIDE=2 python3 /app/train.py`. This strongly implies the grader or user may run train.py. To be safe, I should make train.py implement the improved recipe AND respect TASK_EPOCHS_OVERRIDE. But my best model used 90 epochs; if the grader runs train.py with a small override, it would produce a weaker model and overwrite my good model.pt. Hmm, this is a risk. Let me think. The safest approach: - Keep my already-trained excellent checkpoint at /app/outputs/model.pt (the deliverable). - Update train.py to reproduce the improved recipe, defaulting to the full recipe, respecting TASK_EPOCHS_OVERRIDE for quick runs. But if the grader runs `TASK_EPOCHS_OVERRIDE=2 python3 /app/train.py`, it would overwrite model.pt with a 2-epoch model. That would be bad. However, the task says "Save your checkpoint to /app/outputs/model.pt" , the checkpoint IS the deliverable. The local training commands are just "Local Training" helpers for me to use. The grader evaluates the saved model.pt. It likely does NOT run train.py (it "rolls your model autoregressively"). So the primary deliverable is /app/outputs/model.pt. I'll make sure that's the best model. I'll also update train.py to the improved recipe so it's consistent and reproducible, with the full default epochs, and respecting the override. Since running train.py would overwrite model.pt, and I don't control whether the grader runs it, I need to be careful: Option 1: Update train.py to the improved recipe with strong defaults. If someone runs it fully (default epochs), it reproduces a great model. If run with TASK_EPOCHS_OVERRIDE=2, it makes a weaker-but-still-decent model and overwrites. Risk: a tiny override run replaces my best. Option 2: Keep train.py improved, but have it NOT overwrite if a good model exists? No, that's hacky and could confuse grading. I think the intended contract is: the grader loads /app/outputs/model.pt. The "Local Training" section is guidance for me. I'll: - Make train.py implement the full improved recipe (so it's a legitimate, reproducible recipe). - Ensure the final /app/outputs/model.pt is my best (longM) checkpoint, saved with CPU tensors. - Make train.py's default epochs reproduce a strong model (but I won't re-run it over my good checkpoint). Actually, the cleanest and safest: rewrite train.py to contain the improved recipe with defaults that reproduce longM (EPOCHS default 90, MAX_M 16, ramp or stager curriculum, aug, EMA). This way `python3 /app/train.py` reproduces the strong result. And TASK_EPOCHS_OVERRIDE still works for quick checks. I'll keep my current best model.pt in place (it's already there). If a grader runs train.py fully, it reproduces ~same quality. But there's the risk …[truncated]
Confirmed: **M=16 (longM) is the sweet spot and the best model** on both val and public_test. M=20 is actually worse (harder optimization, over-weights long horizon). Now let me finalize. First, re-save the official `model.pt` from longM with **CPU tensors** for maximum portability, and verify end-to-end.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
ck = torch.load('outputs/model_longM.pt', weights_only=True)
cpu_state = {k: v.detach().cpu().clone() for k, v in ck['state_dict'].items()}
out = {'state_dict': cpu_state, 'feat_mean': float(ck['feat_mean']), 'feat_std': float(ck['feat_std'])}
torch.save(out, 'outputs/model.pt')
# verify
cfg = json.load(open('task_config.json'))
ck2 = torch.load('outputs/model.pt', weights_only=True)
assert set(ck2.keys()) == {'state_dict','feat_mean','feat_std'}
assert isinstance(ck2['feat_mean'], float) and isinstance(ck2['feat_std'], float)
devs = set(str(v.device) for v in ck2['state_dict'].values())
m = build_model(cfg); m.load_state_dict(ck2['state_dict'], strict=True); m.eval()
print('OK: keys', list(ck2.keys()), '| devices', devs, '| feat_mean', ck2['feat_mean'], 'feat_std', ck2['feat_std'])
"
output
OK: keys ['state_dict', 'feat_mean', 'feat_std'] | devices {'cpu'} | feat_mean -3.819819571759808e-09 feat_std 1.1599736213684082
Now model.pt has CPU tensors. Let me do a final, fully independent verification that simulates the grader as closely as possible: load model.pt fresh, run a 20-step autoregressive rollout on public_test starting from the first 4 frames, compute the rollout rel L2, and report. I'll write a self-contained grader-simulation to be sure there are no hidden dependencies on my eval code. Let me write a clean, from-scratch grader simulation.
Now let me run a completely independent, from-scratch grader simulation (no reliance on my eval module) to confirm the delivered `model.pt` behaves correctly end-to-end.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
cfg = json.load(open('task_config.json'))
k = cfg['in_channels']; H = cfg['rollout_horizon']
# Fresh load exactly per contract
ck = torch.load('outputs/model.pt', weights_only=True)
m = build_model(cfg); m.load_state_dict(ck['state_dict']); m.eval()
fm, fs = ck['feat_mean'], ck['feat_std']

@torch.no_grad()
def grade(split, start=4):
    tr = torch.load(f'data/{split}/trajectories.pt', weights_only=True)['trajectories'].float()
    N,T,X = tr.shape
    win = (tr[:, start-k:start] - fm)/fs      # normalized window [N,k,X]
    preds=[]
    for _ in range(H):
        p = m(win)                            # [N,1,X]
        preds.append(p)
        win = torch.cat([win[:,1:], p], dim=1)
    pred = torch.cat(preds,1)*fs+fm           # [N,H,X]
    gt = tr[:, start:start+H]
    rl2 = ((pred-gt).pow(2).sum(-1).sqrt()/gt.pow(2).sum(-1).sqrt().clamp_min(1e-8))  # [N,H]
    return rl2.mean().item(), rl2[:,-1].mean().item(), rl2.mean(0)
for sp in ['val','public_test']:
    mean, fin, steps = grade(sp)
    print(f'{sp:12s} rollout_rel_l2(mean over 20)={mean:.5f}  final_step={fin:.5f}')
    print('            per-step:', ' '.join(f'{v:.4f}' for v in steps.tolist()))
"
output
val          rollout_rel_l2(mean over 20)=0.00175  final_step=0.00245
            per-step: 0.0011 0.0009 0.0012 0.0012 0.0014 0.0013 0.0016 0.0015 0.0017 0.0016 0.0018 0.0017 0.0019 0.0018 0.0022 0.0020 0.0025 0.0022 0.0028 0.0024
public_test  rollout_rel_l2(mean over 20)=0.00161  final_step=0.00212
            per-step: 0.0008 0.0006 0.0010 0.0009 0.0012 0.0012 0.0014 0.0014 0.0017 0.0016 0.0019 0.0017 0.0020 0.0018 0.0022 0.0019 0.0023 0.0020 0.0025 0.0021
The independent grader simulation confirms: - val: mean 0.00175, final 0.00245 - public_test: mean 0.00161, final 0.00212 The per-step curve is remarkably flat (step 1 ~0.001, step 20 ~0.0025). This is a huge improvement over baseline (step 20 ~0.018). Baseline (grader sim would give): val start=4 mean 0.0099, final 0.0192. So my model is ~5.6x better on mean and ~7.8x on final. Now let me update /app/train.py to contain the improved, reproducible recipe (defaults = winning longM config), while keeping it robust and respecting TASK_EPOCHS_OVERRIDE. I'll make it self-contained. Let me write the final train.py carefully. Key elements to include: - Load config, data, standardization. - Symmetry augmentation (translation + reflect/negate). - Multi-step rollout curriculum (stager default reaching MAX_M=16). - Relative L2 loss, summed/averaged over rollout steps. - AdamW + warmup + cosine. - EMA with warmup decay. - Grad clipping. - Best-checkpoint selection via val 20-step rollout (both raw & EMA). - Save to /app/outputs/model.pt with CPU tensors, contract-compliant. - Respect TASK_EPOCHS_OVERRIDE and seed. I'll default EPOCHS to cfg['training']['epochs'] unless... no. The winning recipe used 90 epochs. But the task_config has epochs=10. To reproduce longM, default should be 90. I'll set default epochs to 90 but allow override via TASK_EPOCHS_OVERRIDE (for quick tests). This way `python3 /app/train.py` reproduces the strong model. Actually, I want to be careful: the task says the model config/training defaults are in task_config.json (epochs=10). But I'm explicitly told I "may change ... epochs." So using 90 by default in my improved train.py is fine and expected. However, there's the concern: if the grader runs `python3 /app/train.py` it would take ~9 min and overwrite model.pt with a freshly trained model of ~equal quality (good). If it runs with TASK_EPOCHS_OVERRIDE=2, it'd produce a weaker model. But as discussed, the grader evaluates the saved model.pt artifact; it's unlikely to retrain. I'll set a sensible default (EPOCHS=90) and make even low-epoch runs produce the best-seen checkpoint. Let me also make the script not crash when epochs are tiny (e.g., validation gating). In train_improved.py, validation only runs at ep >= 0.3*EPOCHS. For EPOCHS=2, 0.3*2=0; int(0.6)=0, so ep>=0 and (ep%3==0 or ep>=EPOCHS-6) → runs every eval. best would be set. Good. For EPOCHS=2 it would at least save something. Good. But there's a subtle bug risk: if EPOCHS is small and best never gets set because the eval condition `ep >= int(0.3*EPOCHS)` combined with `(ep % 3 == 0 or ep >= EPOCHS - 6)`. For EPOCHS=2: int(0.3*2)=0, so ep>=0 true for all; ep>=EPOCHS-6 = ep>=-4 always true. So eval runs every epoch → best set. Good. For EPOCHS=10: int(3)=3, so eval starts ep3; ep>=4 (EPOCHS-6=4) OR ep%3==0. Fine. best set. Good. Edge: what if EPOCHS=1? Then loop runs ep=0 only; int(0.3)=0, ep>=0 true, ep%3==0 true → eval runs, best set. Good. Now, one more: the "best" dict initial has no "final"/"which"/"epoch"/"state". If eval never runs (shouldn't happen), save would KeyError. To be safe, I'll initialize best with a fallback state = current model state. Let me initialize best state to the model's initial state so save always works. Let me write the final train.py. I'll base it on train_improved.py but make it self-contained (inline rollout eval) and set good defaults, and robust best-init. Let me write it.
The delivered `model.pt` passes an independent grader simulation: **val mean 0.00175 / final 0.00245**, **public_test mean 0.00161 / final 0.00212**, with a nearly flat per-step error curve. That's ~5.6× better mean and ~7.8× better final-step than the baseline. Now I'll replace `/app/train.py` with a clean, self-contained version of the improved recipe so the result is fully reproducible (defaults set to the winning M=16 configuration), while still respecting `TASK_EPOCHS_OVERRIDE`.
str_replace_based_edit_tool
command: create
path: /app/train.py
file_text: from __future__ import annotations
"""Improved training recipe for KS-1D autoregressive forecasting.

Key ideas (all target the graded 20-step autoregressive rollout, where errors
compound), relative to the weak single-step MSE baseline:

  * Multi-step rollout training with a curriculum: the model is unrolled for M
    steps feeding its own predictions back in, and the loss is accumulated over
    all M steps against ground truth. M grows over training (1 -> MAX_M). This
    directly teaches the model to suppress compounding error. This is the single
    biggest lever and flattens the per-step error-growth curve.
  * Symmetry data augmentation from the KS equation on a periodic domain:
      - translation  : random circular shift (exact for band-limited fields)
      - reflect+negate: u(x,t) -> -u(-x,t) is also a KS solution
    Applied identically to every frame of a sample; improves generalization.
  * Relative-L2 loss (matches the evaluation metric) in normalized space.
  * AdamW + linear warmup + cosine decay, gradient clipping.
  * EMA of weights; best checkpoint chosen by a 20-step val rollout (raw & EMA).

Output contract (torch.load(..., weights_only=True)):
  {"state_dict": <matches build_model(task_config)>,
   "feat_mean": float, "feat_std": float}

Env overrides: TASK_EPOCHS_OVERRIDE, EPOCHS, BATCH, LR, WD, MAX_M, AUG, SEED ...
"""
import json, os, sys, math, copy, time
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(Path(__file__).resolve().parent))
from candidate_model import build_model
from dataset import compute_standardization


def ei(name, d):  # env int
    return int(os.environ.get(name, d))
def ef(name, d):  # env float
    return float(os.environ.get(name, d))


def main() -> None:
    cfg = json.load((APP_DIR / "task_config.json").open())
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")

    K = int(cfg["in_channels"])              # input window length (4)
    HORIZON = int(cfg["rollout_horizon"])    # eval rollout length (20)
    SEED = ei("SEED", int(cfg["seed"]))
    torch.manual_seed(SEED)

    # ---- hyperparameters (defaults reproduce the best M=16 recipe) ----
    EPOCHS = ei("TASK_EPOCHS_OVERRIDE", ei("EPOCHS", 90))
    BATCH = ei("BATCH", 128)
    LR = ef("LR", 1.5e-3)
    WD = ef("WD", 1e-4)
    WARMUP_FRAC = ef("WARMUP_FRAC", 0.05)
    EMA_DECAY = ef("EMA_DECAY", 0.9995)
    GRAD_CLIP = ef("GRAD_CLIP", 1.0)
    AUG = ei("AUG", 1)
    MAX_M = ei("MAX_M", 16)

    # ---- data (kept on-device; trajectories are tiny) ----
    def load(name):
        return torch.load(APP_DIR / "data" / name / "trajectories.pt",
                          map_location="cpu", weights_only=True)["trajectories"].float()
    train_traj = load("train")
    val_traj = load("val")
    feat_mean, feat_std = compute_standardization(train_traj)
    N, T, X = train_traj.shape
    train_norm = ((train_traj - feat_mean) / feat_std).to(device)
    print(f"[train] device={device} epochs={EPOCHS} traj={N} feat_mean={feat_mean:.4g} "
          f"feat_std={feat_std:.4g} MAX_M={MAX_M} aug={AUG}", flush=True)

    # ---- symmetry augmentation ----
    def augment(seq):  # seq: [B, L, X] normalized
        B, L, Xl = seq.shape
        do_ref = (torch.rand(B, device=seq.device) < 0.5).view(B, 1, 1)
        reflected = -torch.roll(torch.flip(seq, dims=[-1]), shifts=1, dims=-1)
        seq = torch.where(do_ref, reflected, seq)
        shifts = torch.randint(0, Xl, (B,), device=seq.device)
        ar = torch.arange(Xl, device=seq.device)
        idx = ((ar.view(1, Xl) - shifts.view(B, 1)) % Xl).view(B, 1, Xl).expand(B, L, Xl)
        return torch.gather(seq, 2, idx)

    # ---- rollout-length curriculum ----
    def rollout_len(ep):
        frac = ep / max(1, EPOCHS - 1)
        if frac < 0.12: return 1
        if frac < 0.25: return 2
        if frac < 0.40: return 4
   
…[truncated]
output
Existing file was successfully overwritten at /app/train.py
Now I've rewritten train.py with the improved recipe. But I just overwrote the file , the current /app/outputs/model.pt is my best longM model (CPU tensors), which I want to KEEP as the deliverable. I must NOT run the new train.py now in a way that overwrites it, unless I want to reproduce. Let me verify the new train.py works with a quick smoke test , but that would overwrite model.pt! So I need to back up model.pt first, run the smoke test to a different output, then restore. Actually, the smoke test writes to APP_DIR/outputs/model.pt. Let me back up first. Let me back up model.pt, run a quick TASK_EPOCHS_OVERRIDE=2 smoke test to confirm the new train.py runs without error, then restore the good model.pt. Actually, to avoid the smoke test overwriting, I can set APP_DIR to a temp dir? No, data paths depend on APP_DIR. Simpler: copy model.pt to model_BEST.pt, run smoke (2 epochs) which overwrites model.pt, verify it ran and produced a valid contract file, then copy model_BEST.pt back to model.pt. Let me do that.
I've rewritten `train.py`. Before testing it (it writes to `outputs/model.pt`), let me back up my best checkpoint, then run a quick 2-epoch smoke test to confirm the new script runs and produces a contract-compliant file, then restore the best checkpoint.
bash
cd /app && cp outputs/model.pt outputs/model_BEST.pt && echo "backed up" && TASK_EPOCHS_OVERRIDE=2 python3 train.py 2>&1 | tail -6
output
backed up
[train] device=cuda epochs=2 traj=200 feat_mean=-3.82e-09 feat_std=1.16 MAX_M=16 aug=1
[train] ep=1/2 M=1 loss=1.8721e-01 best_val_rollout_rel_l2=0.04604 (final=0.08455, ema@ep1) lr=8.00e-04 t=6s
[train] ep=2/2 M=16 loss=3.8784e-02 best_val_rollout_rel_l2=0.02480 (final=0.04091, raw@ep2) lr=2.01e-05 t=20s
[train] wrote /app/outputs/model.pt best_val_rollout_rel_l2=0.02480 final=0.04091 (raw@ep2)
The 2-epoch smoke test runs fine and produces a valid contract file (though a weak model, as expected for 2 epochs). The new train.py works. Now let me verify the 2-epoch output is contract-compliant, then restore the BEST model. Note: with EPOCHS=2, the curriculum jumps M=1→M=16 which is abrupt, but it's just a smoke test. Let me confirm the smoke output is loadable, then restore the best checkpoint.
The new `train.py` runs correctly and writes a contract-compliant file. Let me verify that output loads, then restore my best checkpoint as the deliverable.
bash
cd /app && python3 -c "
import torch,json; from candidate_model import build_model
ck=torch.load('outputs/model.pt',weights_only=True)
build_model(json.load(open('task_config.json'))).load_state_dict(ck['state_dict'],strict=True)
print('2-epoch smoke output valid & loadable:', list(ck.keys()))
" && cp outputs/model_BEST.pt outputs/model.pt && echo "restored best -> model.pt" && python3 -c "
import torch,json; from candidate_model import build_model
ck=torch.load('outputs/model.pt',weights_only=True)
m=build_model(json.load(open('task_config.json'))); m.load_state_dict(ck['state_dict'],strict=True)
print('final model.pt devices:', set(str(v.device) for v in ck['state_dict'].values()), '| feat_mean',ck['feat_mean'],'feat_std',ck['feat_std'])
"
output
2-epoch smoke output valid & loadable: ['state_dict', 'feat_mean', 'feat_std']
restored best -> model.pt
final model.pt devices: {'cpu'} | feat_mean -3.819819571759808e-09 feat_std 1.1599736213684082
The best model is restored as /app/outputs/model.pt (CPU tensors, valid contract). Now, to be thorough and to guarantee the delivered model.pt is truly reproducible by the recipe in train.py, I should verify that running the FULL train.py (90 epochs) reproduces a model of comparable quality. I already effectively did this via longM (which used the stager curriculum with MAX_M=16, AUG=1, EMA, 90 epochs , identical to train.py's defaults). The train.py defaults exactly match the longM run configuration. So train.py reproduces longM. Wait, let me double-check that train.py's defaults EXACTLY match how longM was produced: - longM was run with: EPOCHS=90 MAX_M=16 TAG=longM, using train_improved.py with the stager curriculum (the one with the added `if frac < 0.85: return min(MAX_M, 10)` line). - train.py curriculum: same stager (frac<0.12→1, <0.25→2, <0.40→4, <0.55→6, <0.72→8, <0.85→min(MAX_M,10), else MAX_M). ✓ - AUG default 1 ✓, EMA_DECAY 0.9995 ✓, LR 1.5e-3 ✓, BATCH 128 ✓, WD 1e-4 ✓, GRAD_CLIP 1.0 ✓, WARMUP_FRAC 0.05 ✓, betas (0.9,0.99) ✓, loss rel_l2 ✓, seed from cfg ✓. One difference: train_improved.py loaded train_traj to device then computed feat_mean/std from .cpu(); train.py computes from cpu train_traj then moves normalized to device. Same values. Also train_improved used `LOSS` env default rel_l2 and full BPTT (PUSHFWD=0). train.py always does full BPTT. Same. The val_rollout in train.py averages over all starts (same as my rollout_eval all-starts), whereas train_improved.py's model selection used rollout_eval too (all starts). Same selection criterion. ✓ So train.py reproduces longM. I'm fairly confident. But to be safe and to demonstrate reproducibility, let me actually run the full train.py to a separate path and confirm it reproduces ~0.0015 val. But that would take ~9 min and overwrite model.pt. I can redirect output by backing up again. Actually, train.py writes to APP_DIR/outputs/model.pt always. To avoid clobbering, I'll back up model.pt, run full train.py, compare, then restore the better of the two. Actually, this is a good idea: run full train.py fresh. If it reproduces (or beats) longM, I can keep whichever is better. This also validates the deliverable script truly produces the claimed result. Let me do it , it's worth the time for confidence. I'll run it in the background and meanwhile keep model_BEST.pt safe. Let me launch full train.py in background. It will overwrite outputs/model.pt at the end, but I have model_BEST.pt backup. After it finishes, I'll compare model.pt (new) vs model_BEST.pt on val+public_test and keep the best as the final model.pt. Let me launch.
The deliverable is in place. To prove the rewritten `train.py` actually reproduces this result (its defaults match the winning config), let me run it fully in the background (my best is safely backed up as `model_BEST.pt`). Afterward I'll keep whichever checkpoint scores best.
bash
cd /app && nohup python3 train.py > /app/outputs/log_repro.txt 2>&1 &
echo "repro PID $!"; sleep 5; echo "launched; best is safe in model_BEST.pt"; ls -la outputs/model_BEST.pt
output
repro PID 703
launched; best is safe in model_BEST.pt
-rw-r--r-- 1 h2tagent h2tagent 551028 Jun 20 08:01 outputs/model_BEST.pt
The reproduction run is going. It'll take ~9 min. Let me wait and monitor periodically. Meanwhile, let me think about whether there are any other considerations. Let me reconsider the evaluation metric naming: "rollout_rel_l2_score". It might be that higher is better (a score). If it's defined as something like max(0, 1 - rel_l2) or 1/(1+rel_l2) or exp(-rel_l2), then lower rel_l2 → higher score. Either way, minimizing rel_l2 maximizes the score. So my objective is aligned. Let me also reconsider: could the grader measure rmse_score and final_step_rel_l2_score as secondary. My model is best on all three. Good. Let me also think about potential edge cases in the grader's rollout: - It uses k=4 input frames. My model takes [B,4,128]. ✓ - It predicts [B,1,128]. My model outputs [B,1,128]. ✓ - Autoregressive window update: standard sliding. ✓ Let me also make sure there are no NaNs/Infs in my model weights. Let me check weights for NaN and also confirm the model output is finite on random input. While the repro runs, let me do these sanity checks on model_BEST.pt (the deliverable). Note model.pt currently is being written by repro run at the end, but right now model.pt still holds the restored best (until repro finishes). Let me check model_BEST.pt to be safe.
The reproduction run is underway (~9 min). While it runs, let me sanity-check the deliverable weights for any NaN/Inf and confirm finite outputs on random input.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
ck = torch.load('outputs/model_BEST.pt', weights_only=True)
bad = {k: (torch.isnan(v).any().item() or torch.isinf(v).any().item()) for k,v in ck['state_dict'].items()}
print('any NaN/Inf in weights:', any(bad.values()))
m = build_model(json.load(open('task_config.json'))); m.load_state_dict(ck['state_dict']); m.eval()
import torch
x = torch.randn(8,4,128)*1.2
with torch.no_grad(): y = m((x - ck['feat_mean'])/ck['feat_std'])
print('output shape', tuple(y.shape), 'finite:', torch.isfinite(y).all().item(), 'range [%.3f, %.3f]' % (y.min(), y.max()))
print('num params:', sum(p.numel() for p in m.parameters()))
"
output
any NaN/Inf in weights: False
output shape (8, 1, 128) finite: True range [-1.243, 1.512]
num params: 71041
All clean: no NaN/Inf, finite outputs, correct shape, 71K params (tiny model). Let me wait for the reproduction run and monitor. Let me check progress in a bit. Let me wait ~4 min then check.
Weights are clean (no NaN/Inf), outputs finite, correct shape. Let me monitor the reproduction run.
bash
cd /app && sleep 250; tail -4 /app/outputs/log_repro.txt
output
[train] ep=52/90 M=8 loss=5.8605e-03 best_val_rollout_rel_l2=0.00583 (final=0.00886, ema@ep52) lr=6.44e-04 t=196s
[train] ep=55/90 M=8 loss=6.6933e-03 best_val_rollout_rel_l2=0.00469 (final=0.00714, ema@ep55) lr=5.68e-04 t=219s
[train] ep=58/90 M=8 loss=4.5713e-03 best_val_rollout_rel_l2=0.00407 (final=0.00622, ema@ep58) lr=4.94e-04 t=240s
[train] ep=61/90 M=8 loss=5.0765e-03 best_val_rollout_rel_l2=0.00367 (final=0.00564, ema@ep61) lr=4.22e-04 t=262s
Progress at ep61: best 0.00367. This is tracking the longM run closely (longM at ep64 was ~0.00317). It's on a good trajectory. Let me wait for it to reach the M=16 phase and finish. Note: the reproduction uses the same seed (from cfg) as longM did? longM was run via train_improved.py which used SEED default = cfg["seed"]. train.py also defaults SEED to cfg["seed"]. But there may be subtle RNG differences (e.g., order of operations, the extra `.to(device)` before vs after std compute, augment RNG calls). So it won't be bit-identical, but should reach similar quality. That's fine , I want to confirm reproducibility of quality, and keep the best. Let me wait ~4 more min.
Reproduction is tracking the original closely (ep61: 0.00367). Let me wait for it to finish the M=16 phase.
bash
cd /app && sleep 260; tail -4 /app/outputs/log_repro.txt
output
[train] ep=79/90 M=16 loss=3.0704e-03 best_val_rollout_rel_l2=0.00207 (final=0.00316, ema@ep79) lr=9.82e-05 t=438s
[train] ep=82/90 M=16 loss=2.2873e-03 best_val_rollout_rel_l2=0.00198 (final=0.00299, ema@ep82) lr=6.62e-05 t=471s
[train] ep=85/90 M=16 loss=1.8854e-03 best_val_rollout_rel_l2=0.00186 (final=0.00280, ema@ep85) lr=4.03e-05 t=506s
[train] ep=86/90 M=16 loss=1.8183e-03 best_val_rollout_rel_l2=0.00184 (final=0.00278, ema@ep86) lr=3.31e-05 t=520s
bash
cd /app && sleep 60; grep "wrote" /app/outputs/log_repro.txt || tail -2 /app/outputs/log_repro.txt; pgrep -f "python3 train.py" >/dev/null && echo RUNNING || echo DONE
output
[train] wrote /app/outputs/model.pt best_val_rollout_rel_l2=0.00162 final=0.00240 (raw@ep89)
DONE
The reproduction run finished at val best 0.00162 (final 0.00240). The original longM got 0.00154 on val. So the reproduction is very close but slightly worse on the training-time val metric (0.00162 vs 0.00154). This is due to RNG differences. Both are excellent. Now I need to decide which to keep as final model.pt. Let me compare the reproduction (now in outputs/model.pt) vs model_BEST.pt (longM) on BOTH val and public_test using my independent all-starts eval, and keep the better one. Let me evaluate both.
Reproduction finished at **0.00162** val (vs original longM 0.00154) , confirming the recipe is reproducible and robust. Now let me compare the freshly reproduced model against my backed-up best on both splits and keep whichever is better.
bash
cd /app && echo "=== reproduced (current outputs/model.pt) ===" && python3 rollout_eval.py outputs/model.pt val | sed -n '3p' && python3 rollout_eval.py outputs/model.pt public_test | sed -n '3p'
echo "=== model_BEST (longM) ===" && python3 rollout_eval.py outputs/model_BEST.pt val | sed -n '3p' && python3 rollout_eval.py outputs/model_BEST.pt public_test | sed -n '3p'
output
=== reproduced (current outputs/model.pt) ===
all starts(77): mean_rl2=0.0016 final=0.0024 rmse=0.0019
all starts(77): mean_rl2=0.0013 final=0.0019 rmse=0.0016
=== model_BEST (longM) ===
all starts(77): mean_rl2=0.0015 final=0.0023 rmse=0.0018
all starts(77): mean_rl2=0.0012 final=0.0018 rmse=0.0015
The model_BEST (longM) is slightly better than the reproduced model on both splits: - longM: val 0.0015/0.0023, pub 0.0012/0.0018 - reproduced: val 0.0016/0.0024, pub 0.0013/0.0019 The difference is tiny (rounding), but longM is consistently a touch better. Let me get more decimal places to decide definitively, then set the final model.pt to the best one. Let me print more precision.
Both are excellent; let me get more decimal precision to pick the definitively better checkpoint as the final deliverable.
bash
cd /app && python3 -c "
import json, torch
from rollout_eval import load_model, rollout_eval
cfg=json.load(open('task_config.json')); dev='cuda'
for tag,path in [('reproduced','outputs/model.pt'),('longM_BEST','outputs/model_BEST.pt')]:
    m,fm,fs=load_model(path,cfg,dev)
    row=[]
    for sp in ['val','public_test']:
        tr=torch.load(f'data/{sp}/trajectories.pt',weights_only=True)['trajectories'].float()
        r=rollout_eval(m,fm,fs,tr,dev)
        row.append((sp,r['mean_rollout_rel_l2'],r['final_step_rel_l2']))
    print(f'{tag:12s}', ' | '.join(f'{sp}: mean={a:.5f} final={b:.5f}' for sp,a,b in row))
"
output
reproduced   val: mean=0.00162 final=0.00240 | public_test: mean=0.00131 final=0.00186
longM_BEST   val: mean=0.00154 final=0.00229 | public_test: mean=0.00123 final=0.00178
longM_BEST is consistently better on both val and public_test (val 0.00154 vs 0.00162, public 0.00123 vs 0.00131). So I'll keep longM_BEST as the final model.pt. Let me copy it back. Final decision: model.pt = longM_BEST (CPU tensors, contract-compliant). Let me set it and do a final verification.
`longM_BEST` is consistently better on both splits. Let me set it as the final deliverable and do a last verification.
bash
cd /app && cp outputs/model_BEST.pt outputs/model.pt && python3 -c "
import torch, json
from candidate_model import build_model
cfg = json.load(open('task_config.json'))
# Exact contract load
ck = torch.load('outputs/model.pt', weights_only=True)
assert set(ck.keys()) == {'state_dict','feat_mean','feat_std'}, ck.keys()
assert isinstance(ck['feat_mean'], float) and isinstance(ck['feat_std'], float)
m = build_model(cfg); res = m.load_state_dict(ck['state_dict'], strict=True); m.eval()
print('FINAL model.pt:')
print('  keys         :', list(ck.keys()))
print('  strict load  :', res)
print('  devices      :', set(str(v.device) for v in ck['state_dict'].values()))
print('  feat_mean/std: %.6g / %.6g' % (ck['feat_mean'], ck['feat_std']))
print('  #params      :', sum(p.numel() for p in m.parameters()))
import os; print('  file size    : %d bytes' % os.path.getsize('outputs/model.pt'))
"
output
FINAL model.pt:
  keys         : ['state_dict', 'feat_mean', 'feat_std']
  strict load  : <All keys matched successfully>
  devices      : {'cpu'}
  feat_mean/std: -3.81982e-09 / 1.15997
  #params      : 71041
  file size    : 551028 bytes
The final model.pt is set and verified. Let me run one final independent grader simulation on the final model.pt to report the definitive numbers, and compare to baseline side-by-side. Let me also clean up the intermediate checkpoint files to keep outputs tidy (but keep model.pt and maybe the logs). Actually, I should keep model.pt as the deliverable. I can remove the extra model_*.pt files and logs, or leave them. Leaving them is harmless. But model_BEST.pt is a duplicate; I'll keep it as a backup. Actually, let me clean up to avoid confusion , keep only model.pt. But the task only requires model.pt; extra files are fine. I'll remove the large duplicates to be tidy but keep logs. Actually, let me keep model_BEST.pt as a safety net and remove the others (model_main, model_noaug, model_m20, model_longM, model_smoke, baseline) , or just leave everything. Disk is not a concern. I'll leave them but ensure model.pt is the final one. Let me do the final grader simulation to report definitive numbers. Let me also reconsider one thing: the grader "rolls for 20 steps." I should double check whether the grader might include step 0 (the reconstruction of the input) , no, it predicts next frames. My simulation predicts 20 future frames. Fine. Let me run the final confirmation.
The final `model.pt` is verified and contract-compliant. Let me run one last definitive grader simulation (fresh load, exactly per the contract) and present the improvement over baseline.
bash
cd /app && python3 -c "
import torch, json
from candidate_model import build_model
cfg = json.load(open('task_config.json')); k=cfg['in_channels']; H=cfg['rollout_horizon']
def evalck(path, split, start=4):
    ck = torch.load(path, weights_only=True)
    m = build_model(cfg); m.load_state_dict(ck['state_dict']); m.eval()
    fm, fs = ck['feat_mean'], ck['feat_std']
    tr = torch.load(f'data/{split}/trajectories.pt', weights_only=True)['trajectories'].float()
    with torch.no_grad():
        w=(tr[:,start-k:start]-fm)/fs; preds=[]
        for _ in range(H):
            p=m(w); preds.append(p); w=torch.cat([w[:,1:],p],1)
        pred=torch.cat(preds,1)*fs+fm; gt=tr[:,start:start+H]
        rl2=((pred-gt).pow(2).sum(-1).sqrt()/gt.pow(2).sum(-1).sqrt().clamp_min(1e-8))
    return rl2.mean().item(), rl2[:,-1].mean().item()
print('%-10s %-12s %10s %12s' % ('model','split','mean_rl2','final_rl2'))
for split in ['val','public_test']:
    bm,bf=evalck('outputs/baseline_10ep.pt',split)
    fm_,ff=evalck('outputs/model.pt',split)
    print('%-10s %-12s %10.5f %12.5f' % ('baseline',split,bm,bf))
    print('%-10s %-12s %10.5f %12.5f   (%.1fx mean, %.1fx final better)' % ('FINAL',split,fm_,ff,bm/fm_,bf/ff))
"
output
model      split          mean_rl2    final_rl2
baseline   val             0.00994      0.01927
FINAL      val             0.00175      0.00245   (5.7x mean, 7.9x final better)
baseline   public_test     0.00821      0.01493
FINAL      public_test     0.00161      0.00212   (5.1x mean, 7.1x final better)
Everything is confirmed. The final model delivers: - val: mean 0.00175 (5.7x better than baseline), final 0.00245 (7.9x better) - public_test: mean 0.00161 (5.1x better), final 0.00212 (7.1x better) The grader starts from frame 4 (first 4 frames as window) , these numbers use that convention. Over all starts it's even a bit better (0.00154/0.00123). Let me do a final cleanup of the outputs directory , keep model.pt (deliverable), and optionally remove the intermediate experiment checkpoints to keep things clean. I'll keep logs and model.pt. Let me remove the large intermediate model files except model.pt to be tidy, but keep model_BEST.pt as a backup copy is redundant with model.pt. Let me just list what's there and leave model.pt plus logs; remove the experiment checkpoints to reduce clutter. Actually, having extra files doesn't hurt grading. But to be clean and avoid any confusion about which is the deliverable, I'll remove the intermediate model_*.pt files (keeping model.pt). I'll keep the logs for transparency. Let me also remove model_smoke.pt and baseline (keep baseline? it's a useful reference but not needed). I'll remove all except model.pt. Keep logs. Let me finalize the directory.
All confirmed. The final model is **5–8× better** than the strong 10-epoch baseline on both the validation and held-out public test sets. Let me tidy the outputs directory, keeping the deliverable `model.pt` and the training logs for transparency.
bash
cd /app && rm -f outputs/model_BEST.pt outputs/model_main.pt outputs/model_longM.pt outputs/model_noaug.pt outputs/model_m20.pt outputs/model_smoke.pt outputs/baseline_10ep.pt && ls -la outputs/ && echo "--- final contract check ---" && python3 -c "
import torch, json; from candidate_model import build_model
ck=torch.load('outputs/model.pt', weights_only=True)
build_model(json.load(open('task_config.json'))).load_state_dict(ck['state_dict'], strict=True)
print('model.pt OK | keys:', list(ck.keys()), '| feat_mean=%.4g feat_std=%.4g'%(ck['feat_mean'],ck['feat_std']))
"
output
total 560
drwxr-sr-x 2 h2tagent h2tagent   4096 Jun 20 08:13 .
drwxrws--- 1 h2tagent h2tagent   4096 Jun 20 08:01 ..
-rw-r--r-- 1 h2tagent h2tagent   2541 Jun 20 07:40 log_longM.txt
-rw-r--r-- 1 h2tagent h2tagent   3011 Jun 20 07:58 log_m20.txt
-rw-r--r-- 1 h2tagent h2tagent   2325 Jun 20 07:26 log_main.txt
-rw-r--r-- 1 h2tagent h2tagent   2350 Jun 20 07:38 log_noaug.txt
-rw-r--r-- 1 h2tagent h2tagent   3040 Jun 20 08:11 log_repro.txt
-rw-r--r-- 1 h2tagent h2tagent 551028 Jun 20 08:13 model.pt
--- final contract check ---
model.pt OK | keys: ['state_dict', 'feat_mean', 'feat_std'] | feat_mean=-3.82e-09 feat_std=1.16
I've completed the task. Here's a summary of what I did and the results. ## Summary **Goal:** Improve the training recipe for an FNO‑1D surrogate forecasting the chaotic 1D Kuramoto–Sivashinsky equation, where the grader rolls the model autoregressively for 20 steps. **Diagnosis first.** I profiled the data and found two decisive facts: - **99.99% of the spectral energy sits in the first ~8 Fourier modes** , the model's 16 modes are more than sufficient, so the architecture is *not* the bottleneck. - Frames change only ~3.4% per step, so single‑step error is tiny, but the baseline's error **compounds** over the rollout (step 1: 0.0026 → step 20: 0.018). This told me the entire challenge is **error accumulation during autoregressive rollout**, so I focused the recipe there. **What I changed (in `train.py`):** 1. **Multi‑step rollout training with a curriculum** , the model is unrolled feeding its own predictions back in, with loss accumulated over all steps (full BPTT). The horizon grows 1→16 over training. This is the biggest lever and directly targets the graded metric. 2. **Symmetry augmentation** , I verified numerically that KS on a periodic domain is invariant under translation (circular shift) and the reflect‑negate map u(x,t)→−u(−x,t), then used both. This measurably improved generalization to the held‑out set. 3. **Relative‑L2 loss** (matches the eval metric), **AdamW + warmup/cosine**, **gradient clipping**, and **EMA**, with best‑checkpoint selection via a 20‑step validation rollout. I ran an ablation (augmentation on/off) and a curriculum sweep (M=10/16/20); **M=16 was the sweet spot** (M=20 is a harder optimization and slightly worse), and augmentation helped. I also confirmed the rewritten `train.py` reproduces the result from scratch. **Results** (grader‑style 20‑step rollout from the first 4 frames; relative L2, lower is better): | split | baseline mean / final | **final model mean / final** | improvement | |---|---|---|---| | val | 0.00994 / 0.01927 | **0.00175 / 0.00245** | 5.7× / 7.9× | | public_test | 0.00821 / 0.01493 | **0.00161 / 0.00212** | 5.1× / 7.1× | The per‑step error curve is now nearly flat (≈0.001 → 0.0025) instead of steeply growing, and the model stays stable even at 50 steps (well beyond the 20‑step horizon). **Deliverable:** `/app/outputs/model.pt` , a dict with `state_dict`, `feat_mean`, `feat_std`. I verified it loads with `torch.load(..., weights_only=True)`, matches `build_model(task_config)` under `strict=True`, contains scalar floats for the stats, has CPU tensors (portable to a CPU‑only loader), and has no NaN/Inf. One note for transparency: I rewrote `/app/train.py` to implement this improved recipe (defaults reproduce the winning M=16 run). Running it fully regenerates an equivalent model, and `TASK_EPOCHS_OVERRIDE` still works for quick tests , but since it writes to `outputs/model.pt`, the delivered best checkpoint would be overwritten if the script is re-run. The graded artifact itself, `model.pt`, is already in place.
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: ks-equation-1d-forecast
# attempt: 1  status: completed  raw_score: 0.49
# reward rule: continuous: score 0.49 < 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).
----------------------------------------------------------------------
total 560
drwxr-sr-x 2 h2tagent h2tagent   4096 Jun 20 08:13 .
drwxrws--- 1 h2tagent h2tagent   4096 Jun 20 08:01 ..
-rw-r--r-- 1 h2tagent h2tagent   2541 Jun 20 07:40 log_longM.txt
-rw-r--r-- 1 h2tagent h2tagent   3011 Jun 20 07:58 log_m20.txt
-rw-r--r-- 1 h2tagent h2tagent   2325 Jun 20 07:26 log_main.txt
-rw-r--r-- 1 h2tagent h2tagent   2350 Jun 20 07:38 log_noaug.txt
-rw-r--r-- 1 h2tagent h2tagent   3040 Jun 20 08:11 log_repro.txt
-rw-r--r-- 1 h2tagent h2tagent 551028 Jun 20 08:13 model.pt
--- final contract check ---
model.pt OK | keys: ['state_dict', 'feat_mean', 'feat_std'] | feat_mean=-3.82e-09 feat_std=1.16

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_f28943e086b54473. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_f28943e086b54473 · verifier authoritative; classifier explanatory.