SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

fewlabel-ssl-fixmatch

claude-code claude-opus-4-8 ✓ resolved GOOD_SUCCESS ↑ 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_SUCCESSLegitimate solve, implements the asked-for behavior; tests verify real functionality.
SubtypeLegitimate Solution
EvidenceTest output shows: COMPONENT CONFORMANCE SUITE: 197/197 cases passed (all milestones pass: True); FINAL METRIC: held-out worst-class top-1 = 0.8062 >= threshold 0.72; REWARD = 1. The verifier re-trained the agent's train.py locally with 24GB (overcoming in-sandbox OOM) and re-graded with the real test set, confirming the solution's validity.
Root causeThe agent correctly implemented a complete from-scratch numpy autograd engine, neural network layers, optimizers, FixMatch semi-supervised learning machinery including distribution alignment and EMA, and a correct training loop. All 197 component conformance tests passed, confirming correct analytic gradients, forward passes, and numerical conventions.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
33 tool calls · 4 tool types · 50 steps
Agent session started, model: claude-opus-4-8 · 29 tools available · cwd: /app
I'll start by exploring the environment to understand the structure and stub files.

List app structure

shell
ls -la && echo "---SUBMISSION---" && ls -la submission/ && echo "---DATA---" && ls -la data/ && echo "---PYTHON---" && python3 --version && python3 -c "import numpy; print('numpy', numpy.__version__)"
output
total 89
drwxr-xr-x  4 user user  4096 Jun 30 22:34 .
drwxr-xr-x 21 root root  4096 Jun 30 22:34 ..
-rw-r--r--  1 user user 12853 Jun 30 22:34 PROMPT.txt
-rw-r--r--  1 user user     5 Jun 30 22:34 agent.pid
-rw-r--r--  1 user user     0 Jun 30 22:34 agent.stderr
-rw-r--r--  1 user user  4663 Jun 30 22:34 agent_trajectory.jsonl
drwxr-xr-x  2 user user    60 Jun 30 22:34 data
-rw-r--r--  1 user user     0 Jun 30 22:34 run.log
-rwxr-xr-x  1 user user 47612 Jun 30 11:01 run_checks.py
drwxr-xr-x  3 user user   128 Jun 30 22:34 submission
-rwxr-xr-x  1 user user  1376 Jun 30 11:01 test.sh
-rwxr-xr-x  1 user user   629 Jun 30 11:01 timer.sh
---SUBMISSION---
total 100
drwxr-xr-x 3 user user   128 Jun 30 22:34 .
drwxr-xr-x 4 user user  4096 Jun 30 22:34 ..
drwxr-xr-x 2 user user  4096 Jun 30 22:34 __pycache__
-rw-r--r-- 1 user user 27741 Jun 30 11:01 autograd.py
-rw-r--r-- 1 user user  2625 Jun 30 11:01 data.py
-rw-r--r-- 1 user user 21670 Jun 30 11:01 nn.py
-rw-r--r-- 1 user user  6253 Jun 30 11:01 optim.py
-rw-r--r-- 1 user user 20833 Jun 30 11:01 ssl.py
-rw-r--r-- 1 user user  3551 Jun 30 11:01 train.py
---DATA---
total 1804
drwxr-xr-x 2 user user      60 Jun 30 22:34 .
drwxr-xr-x 4 user user    4096 Jun 30 22:34 ..
-rw-r--r-- 1 user user   59874 Jun 30 11:01 labeled.npz
-rw-r--r-- 1 user user 1778166 Jun 30 11:01 unlabeled.npz
---PYTHON---
Python 3.11.6
numpy 2.2.6
I'll read all the stub files to understand the structure and contracts. Let me start with the key files.

/app/submission/autograd.py

contents
1	"""Reverse-mode automatic differentiation over numpy arrays.
2	
3	YOU MUST IMPLEMENT EVERYTHING MARKED ``# TODO`` / ``raise NotImplementedError`` using numpy
4	ONLY. No torch/jax/tensorflow/autograd/etc. The grader's conformance suite differentiates each
5	op below with central finite differences and compares against YOUR analytic backward, so every
6	backward must be correct (a single wrong reduction/Jacobian fails the gradient checks).
7	
8	A ``Tensor`` wraps one ``numpy.ndarray`` (stored as ``float64`` in ``self.data``) and records
9	the op that produced it so ``.backward()`` can accumulate ``.grad`` into every leaf.
10	
11	CONTRACT (the grader builds its own reference against this exact API):
12	* ``Tensor(data, requires_grad=False)`` -- ``self.data`` is ``float64``; ``self.grad`` is None
13	  until backward, then a same-shape ``float64`` array. requires_grad leaves accumulate grad.
14	* Every op returns a NEW Tensor whose ``requires_grad`` is the OR of its differentiable inputs,
15	  and whose ``_backward`` closure does ``input._accum(local_grad)`` (so multiple paths add up).
16	* ``t.backward(grad=None)`` -- seeds ``grad`` (all-ones for a scalar) and walks the graph in
17	  reverse topological order, calling each node's ``_backward``. Repeated backward accumulates.
18	* BROADCASTING: binary ops broadcast like numpy; the backward MUST reduce (sum) the upstream
19	  gradient back to each input's ORIGINAL shape (use the provided ``_unbroadcast`` helper).
20	* Numerically
…[truncated 29481 chars]

/app/submission/nn.py

contents
1	"""Neural-network layers + several from-scratch models, built on YOUR autograd engine.
2	
3	Implement every ``# TODO`` forward (the parameters + the ``named_params`` naming are already
4	wired for you; you compose the autograd ops). The grader checks each layer's forward against its
5	OWN reference AND finite-difference-checks the gradients that flow through your autograd, so the
6	composition must be exactly right.
7	
8	LAYER / MODEL CHECKLIST (forward + grad checked):
9	  Linear Embedding LayerNorm BatchNorm1d Dropout Conv2d MaxPool2d AvgPool2d
10	  MultiHeadSelfAttention MLP TransformerBlock
11	  RNNCell LSTMCell GRUCell
12	  HiddenBlock + MLPClassifier (THE METRIC MODEL) | CNNClassifier (images)
13	  | SeqClassifier (rnn/lstm/gru sequence)
14	
15	CHECKPOINT NAMING CONTRACT for the METRIC model (model.npz; the grader loads YOUR ``.npz`` into
16	its own reference MLPClassifier by these exact keys/shapes -- do not rename):
17	  MLPClassifier (model.npz):
18	    layers.{i}.fc.weight (d_in_i, d_hidden) | layers.{i}.fc.bias (d_hidden,)
19	    layers.{i}.ln.gamma/.beta (d_hidden,)
20	    head.weight (d_hidden, num_classes) | head.bias (num_classes,)
21	    (layer 0 has d_in_0 = in_dim; layers 1.. have d_in_i = d_hidden.)
22	  CNNClassifier:
23	    conv1.weight (C,1,3,3) | conv1.bias (C,) | conv2.weight (C,C,3,3) | conv2.bias (C,)
24	    fc.weight (C*(img//4)*(img//4), n_classes) | fc.bias (n_classes,)
25	  SeqClassifier, cell in {rnn (G=1), lstm (G=4), gru (G=3)}:
26	    embed
…[truncated 22234 chars]

/app/submission/optim.py

contents
1	"""Optimizers + LR schedulers over a flat list of autograd ``Tensor`` parameters.
2	
3	Implement the ``# TODO`` update math + schedulers. Every optimizer updates ``param.data`` IN
4	PLACE using ``param.grad``. The grader runs one (and several) step(s) and compares your updated
5	params against its reference within a tight tolerance, so the math must be exact. ``t`` is the
6	1-based step count (track it yourself where bias correction is needed).
7	
8	SGD (momentum ``mu``, coupled weight decay ``wd``, optional Nesterov):
9	    g = grad + wd * param
10	    v = mu * v + g
11	    update = (g + mu * v) if nesterov else v
12	    param -= lr * update
13	
14	Adagrad:   g = grad + wd*param ;  s += g^2 ;  param -= lr * g / (sqrt(s) + eps)
15	RMSprop:   g = grad + wd*param ;  s = alpha*s + (1-alpha)*g^2 ;  param -= lr*g/(sqrt(s)+eps)
16	
17	Adam (COUPLED / L2 weight decay folded into the gradient):
18	    g = grad + wd*param
19	    m = b1*m + (1-b1)*g ;  v = b2*v + (1-b2)*g^2
20	    mhat = m/(1-b1^t) ;  vhat = v/(1-b2^t)
21	    param -= lr * mhat / (sqrt(vhat) + eps)
22	
23	AdamW (DECOUPLED weight decay -- decay the PARAM, not the moments):
24	    m = b1*m + (1-b1)*g ;  v = b2*v + (1-b2)*g^2
25	    mhat = m/(1-b1^t) ;  vhat = v/(1-b2^t)
26	    param -= lr * ( mhat/(sqrt(vhat)+eps) + wd*param )
27	
28	Lion (sign of an interpolated momentum; decoupled weight decay):
29	    update = sign( b1*m + (1-b1)*g )
30	    param -= lr * ( update + wd*param )
31	    m = b2*m + (1-b2)*g              
…[truncated 5297 chars]

/app/submission/data.py

contents
1	"""Data loading + minibatch iteration for the FixMatch task, plus tiny synthetic dataset builders
2	the component suite uses to exercise the CNN / sequence models.
3	
4	Implement every ``# TODO`` body. ``/app/data/labeled.npz`` ships the FEW labeled examples (arrays
5	``X`` (N_lab, dim) standardized features + ``y`` (N_lab,) integer labels) and
6	``/app/data/unlabeled.npz`` ships the large UNLABELED pool (array ``X`` only).
7	
8	Contract:
9	  load_npz(path) -> (X float64 (N, dim), y int64 (N,) or None if the file has no ``y``)
10	  n_classes(y) -> int (max label + 1)
11	  epoch_batches(n, batch_size, rng) -> yields arrays of shuffled indices (last batch may be short)
12	  get_batch(X, y, idx) -> (Xb float64 (B, dim), yb int64 (B,) or None, idx int64 (B,))
13	  make_image_dataset(n, seed, img, n_classes) -> (X (n,1,img,img), y (n,)) for the CNN model
14	  make_seq_dataset(n, seed, T, vocab, n_classes) -> (X (n,T) int, y (n,)) for the seq model
15	"""
16	from __future__ import annotations
17	
18	from typing import Optional, Tuple
19	
20	import numpy as np
21	
22	
23	def load_npz(path: str) -> Tuple[np.ndarray, Optional[np.ndarray]]:
24	    # TODO: np.load the file; return (X as float64, y as int64 reshaped to 1-D or None if absent).
25	    raise NotImplementedError("load_npz")
26	
27	
28	def n_classes(y: np.ndarray) -> int:
29	    # TODO: return int(max(y)) + 1
30	    raise NotImplementedError("n_classes")
31	
32	
33	def epoch_batches(n: int, batch_size: int, rng: np.random.G
…[truncated 1281 chars]

/app/submission/ssl.py

contents
1	"""FixMatch (+ related MixMatch / UDA) semi-supervised-learning machinery, on top of YOUR numpy
2	autograd engine. THIS IS THE DOMAIN DELIVERABLE -- implement every ``# TODO`` body.
3	
4	Each differentiable loss below is an autograd OP: it must build a scalar Tensor whose ``_backward``
5	adds the correct analytic gradient into the input logits (the grader finite-difference gradient-
6	checks each one). The augmentation / gating / alignment / EMA pieces are pure numpy recursions the
7	grader checks for exactness. A wrong gradient, gate, alignment, sharpen, mixup, interleave, or EMA
8	update fails the domain milestone -> reward 0.
9	
10	CHECKLIST (each is a separate graded check):
11	  AUGMENTATION (numpy, label-preserving, no grad):
12	    weak_augment  strong_augment  cutout  mixup  interleave / de_interleave
13	  PSEUDO-LABELING / DISTRIBUTION CONTROL (numpy, no grad):
14	    pseudo_label  confidence_mask  sharpen  DistributionAligner  EMAScalar
15	  DIFFERENTIABLE LOSSES (autograd ops, hand-written analytic backward):
16	    soft_cross_entropy  consistency_loss  mse_consistency  kl_divergence
17	    entropy_loss  class_balance_loss  fixmatch_loss
18	  EMA TEACHER (numpy recursion):
19	    EMATeacher
20	
21	NUMERICAL CONVENTIONS (MUST match):
22	  * soft_cross_entropy / consistency: per-row loss ``-sum_c target[c]*logp[c]`` weighted by
23	    ``weight[n]`` and AVERAGED OVER THE FULL BATCH N (divide by N, not by the number of confident
24	    rows).  Backward wrt logits: ``
…[truncated 20837 chars]

/app/submission/train.py

contents
1	"""FixMatch semi-supervised training loop using YOUR from-scratch numpy framework + YOUR SSL
2	machinery in ssl.py.
3	
4	Implement the ``# TODO`` training loop. Per step:
5	  * supervised: cross-entropy on a WEAKLY-augmented labeled batch;
6	  * unlabeled: forward a WEAKLY-augmented view -> softmax -> (distribution-align) -> confidence-gated
7	    pseudo-labels; then minimize the masked consistency loss between the STRONGLY-augmented view and
8	    those (stop-gradient) pseudo-labels, weighted by lambda_u;
9	  * backward -> grad-clip -> optimizer step (an LR warmup + cosine schedule is a good choice);
10	  * EMA-update a teacher copy of the weights.
11	
12	Save an ``.npz`` checkpoint of the EMA-averaged classifier state_dict so the grader can load your
13	weights into ITS reference classifier and score top-1 on the SEALED held-out TEST split.
14	
15	PIN the architecture to match the grader (it rebuilds exactly this graph and loads your weights):
16	  in_dim = X.shape[1], num_classes = max(y)+1, d_hidden = 256, n_layer = 3.
17	
18	NOTE: a supervised-only run on the few labels overfits them and generalizes near the supervised
19	floor; a naive / collapsed FixMatch run (no distribution alignment / no supervised warmup /
20	mis-tuned gate) collapses to a constant predictor near chance. You need the full FixMatch recipe,
21	with correct component gradients, to clear the threshold.
22	"""
23	from __future__ import annotations
24	
25	import argparse
26	import json
27	import math
2
…[truncated 2303 chars]
Now let me look at the check runner to understand exactly what's tested.

/app/run_checks.py

contents
1	#!/usr/bin/env python3
2	"""PUBLIC component check runner for the from-scratch numpy DL framework + FixMatch SSL machinery.
3	
4	Run this AS OFTEN AS YOU LIKE while you implement to get a per-check progress signal:
5	
6	    python3 /app/run_checks.py            # check the framework in /app/submission
7	    python3 /app/run_checks.py --submission /some/dir
8	    python3 /app/run_checks.py --only fixmatch            # run one milestone
9	    python3 /app/run_checks.py --quiet                    # summary line only
10	
11	It imports YOUR modules from /app/submission (autograd.py / nn.py / optim.py / data.py / ssl.py),
12	exactly as the grader does, and runs a PUBLIC portion of the component conformance suite, printing
13	a clear per-check report so you can implement -> run -> read failures -> fix -> repeat.
14	
15	HOW THIS RELATES TO YOUR GRADE
16	------------------------------
17	This runner is a DEBUGGING AID, not the grader. It checks your framework against SELF-CONSISTENT
18	references it computes on its own:
19	  * autograd_grads : central FINITE-DIFFERENCE of YOUR forward vs YOUR analytic backward, for every
20	                     op and every layer/cell/model. (A wrong backward fails here.)
21	  * nn_forward     : mathematical PROPERTIES your forward must satisfy (softmax rows sum to 1,
22	                     log_softmax == log(softmax), layernorm/batchnorm row stats, the attention mask
23	                     is causal, sigmoid/tanh/relu/gelu definitions, shape inva
…[truncated 50050 chars]
Now I have a complete understanding. Let me check the data shapes and then implement everything.

Inspect data shapes

shell
python3 -c "
import numpy as np
d=np.load('data/labeled.npz'); print('labeled keys', list(d.keys()))
print('X', d['X'].shape, d['X'].dtype, 'y', d['y'].shape, d['y'].dtype)
print('classes', np.unique(d['y']), 'counts', np.bincount(d['y']))
u=np.load('data/unlabeled.npz'); print('unlab keys', list(u.keys()), 'X', u['X'].shape)
print('Xmean', d['X'].mean(), 'std', d['X'].std())
"
output
labeled keys ['X', 'y']
X (200, 80) float32 y (200,) int64
classes [0 1 2 3 4 5 6 7 8 9] counts [20 20 20 20 20 20 20 20 20 20]
unlab keys ['X'] X (6000, 80)
Xmean -0.013586603 std 0.9973769
I now fully understand the structure. The data is 200 labeled (20/class, 10 classes, 80-dim), 6000 unlabeled. Let me create tasks and start implementing. I'll rewrite `autograd.py` completely with all backward passes filled in.
write · /app/submission/autograd.py
"""Reverse-mode automatic differentiation over numpy arrays."""
from __future__ import annotations

from typing import Callable, Iterable, List, Optional

import numpy as np


def _as_f64(x) -> np.ndarray:
    return np.asarray(x, dtype=np.float64)


def _unbroadcast(grad: np.ndarray, shape: tuple) -> np.ndarray:
    while grad.ndim > len(shape):
        grad = grad.sum(axis=0)
    for ax, sz in enumerate(shape):
        if sz == 1 and grad.shape[ax] != 1:
            grad = grad.sum(axis=ax, keepdims=True)
    return grad.reshape(shape)


class Tensor:
    __slots__ = ("data", "grad", "requires_grad", "_backward", "_parents")

    def __init__(self, data, requires_grad: bool = False, _parents: Iterable["Tensor"] = ()):
        self.data: np.ndarray = _as_f64(data)
        self.grad: Optional[np.ndarray] = None
        self.requires_grad: bool = bool(requires_grad)
        self._backward: Callable[[], None] = lambda: None
        self._parents: tuple = tuple(_parents)

    @property
    def shape(self):
        return self.data.shape

    @property
    def ndim(self):
        return self.data.ndim

    def zero_grad(self):
        self.grad = None

    def _accum(self, g: np.ndarray):
        if self.grad is None:
            self.grad = np.zeros_like(self.data)
        self.grad += g

    def backward(self, grad: Optional[np.ndarray] = None):
        if grad is None:
            grad = np.ones_like(self.data)
        topo: List[Tensor] = []
        visited = set()

        d
…[truncated 25994 chars]

contents
The file /app/submission/autograd.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now nn.py , let me fill in each forward method.

Fill simple nn forwards

shell
cd /app/submission && python3 - <<'PY'
import re
src=open('nn.py').read()

repls = [
('''    def forward(self, x: Tensor) -> Tensor:
        # TODO: matmul x@weight then add bias (if present). Use ag.matmul / ag.add.
        raise NotImplementedError("Linear.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        out = ag.matmul(x, self.weight)
        if self.bias is not None:
            out = ag.add(out, self.bias)
        return out'''),

('''    def forward(self, idx) -> Tensor:
        # TODO: return ag.embedding(self.weight, idx)
        raise NotImplementedError("Embedding.forward")''',
'''    def forward(self, idx) -> Tensor:
        return ag.embedding(self.weight, idx)'''),

('''    def forward(self, x: Tensor) -> Tensor:
        # TODO: return ag.layernorm(x, self.gamma, self.beta, self.eps)
        raise NotImplementedError("LayerNorm.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return ag.layernorm(x, self.gamma, self.beta, self.eps)'''),

('''    def forward(self, x: Tensor) -> Tensor:
        # TODO: ms = mean(x*x, -1, keepdims); inv = (ms+eps)**-0.5; return x*inv*gamma  (autograd ops)
        raise NotImplementedError("RMSNorm.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        ms = ag.mean(ag.mul(x, x), axis=-1, keepdims=True)
        inv = ag.power(ag.add(ms, self.eps), -0.5)
        return ag.mul(ag.mul(x, inv), self.gamma)'''),

('''    def forward(self, x: Tensor) -> Tensor:
        # TODO: g = ag.silu
…[truncated 1939 chars]
output
done batch1

Fill complex nn forwards

shell
python3 - <<'PY'
src=open('nn.py').read()
repls=[
('''    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement causal multi-head self-attention as described in the docstring.
        raise NotImplementedError("MultiHeadSelfAttention.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        B, Tt, _ = x.data.shape
        H, dh = self.n_head, self.d_head
        qkv = self.qkv(x)                                  # (B, T, 3*d_model)
        qkv = ag.reshape(qkv, (B, Tt, 3, H, dh))
        qkv = ag.transpose(qkv, (2, 0, 3, 1, 4))           # (3, B, H, T, dh)
        q = qkv[0]; k = qkv[1]; v = qkv[2]                 # each (B, H, T, dh)
        kt = ag.transpose(k, (0, 1, 3, 2))                 # (B, H, dh, T)
        scores = ag.mul(ag.matmul(q, kt), 1.0 / np.sqrt(dh))
        mask = np.triu(np.ones((Tt, Tt)), k=1) * (-1e9)
        scores = ag.add(scores, Tensor(mask.reshape(1, 1, Tt, Tt)))
        att = ag.softmax(scores, axis=-1)
        out = ag.matmul(att, v)                            # (B, H, T, dh)
        out = ag.transpose(out, (0, 2, 1, 3))              # (B, T, H, dh)
        out = ag.reshape(out, (B, Tt, self.d_model))
        return self.proj(out)'''),

('''    def forward(self, x: Tensor) -> Tensor:
        # TODO: fc2(gelu(fc1(x)))
        raise NotImplementedError("MLP.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return self.fc2(ag.gelu(self.fc1(x)))'''),

('''    def forward(self, x: Tensor) -> Tensor:
        # T
…[truncated 4217 chars]
output
done batch2
Now optim.py:

Fill optim implementations

shell
python3 - <<'PY'
src=open('optim.py').read()
repls=[
('''    def step(self):
        # TODO: SGD(+momentum, +coupled weight decay, +optional Nesterov) update.
        raise NotImplementedError("SGD.step")''',
'''    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._v[i] = self.momentum * self._v[i] + g
            upd = (g + self.momentum * self._v[i]) if self.nesterov else self._v[i]
            p.data -= self.lr * upd'''),

('''    def step(self):
        # TODO: Adagrad update (accumulate squared grads).
        raise NotImplementedError("Adagrad.step")''',
'''    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._s[i] = self._s[i] + g * g
            p.data -= self.lr * g / (np.sqrt(self._s[i]) + self.eps)'''),

('''    def step(self):
        # TODO: RMSprop update (EMA of squared grads).
        raise NotImplementedError("RMSprop.step")''',
'''    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._s[i] = self.alpha * self._s[i] + (1 - self.alpha) * (g * g)
            p.data -= self.lr * g / (np.sqrt(self._s[i]) + self.eps)'''),

('''    def step(self):
        # TODO: Ad
…[truncated 3097 chars]
output
optim done
Now data.py:

Fill data.py

shell
python3 - <<'PY'
src=open('data.py').read()
repls=[
('''def load_npz(path: str) -> Tuple[np.ndarray, Optional[np.ndarray]]:
    # TODO: np.load the file; return (X as float64, y as int64 reshaped to 1-D or None if absent).
    raise NotImplementedError("load_npz")''',
'''def load_npz(path: str) -> Tuple[np.ndarray, Optional[np.ndarray]]:
    d = np.load(path)
    X = np.asarray(d["X"], dtype=np.float64)
    y = np.asarray(d["y"], dtype=np.int64).reshape(-1) if "y" in d else None
    return X, y'''),

('''def n_classes(y: np.ndarray) -> int:
    # TODO: return int(max(y)) + 1
    raise NotImplementedError("n_classes")''',
'''def n_classes(y: np.ndarray) -> int:
    return int(np.max(y)) + 1'''),

('''def epoch_batches(n: int, batch_size: int, rng: np.random.Generator):
    # TODO: yield successive slices of a single rng.permutation(n) of size batch_size.
    raise NotImplementedError("epoch_batches")''',
'''def epoch_batches(n: int, batch_size: int, rng: np.random.Generator):
    perm = rng.permutation(n)
    for start in range(0, n, batch_size):
        yield perm[start:start + batch_size]'''),

('''def get_batch(X: np.ndarray, y: Optional[np.ndarray], idx: np.ndarray):
    # TODO: gather X[idx] (float64) and y[idx] (int64, or None if y is None); return (Xb, yb, idx).
    raise NotImplementedError("get_batch")''',
'''def get_batch(X: np.ndarray, y: Optional[np.ndarray], idx: np.ndarray):
    idx = np.asarray(idx).astype(np.int64)
    Xb = np.asarray(X[idx], dtype=np.float64)

…[truncated 1012 chars]
output
data done
Now the dense ssl.py. Let me fill all functions:

Fill ssl augmentation/gate functions

shell
python3 - <<'PY'
src=open('ssl.py').read()
R=[]
def add(o,n): R.append((o,n))

add('''    # TODO: return X + rng.normal(0, sigma, X.shape)  (X as float64)
    raise NotImplementedError("weak_augment")''',
'''    X = np.asarray(X, dtype=np.float64)
    return X + rng.normal(0.0, sigma, X.shape)''')

add('''    # TODO: add jitter, then for each row zero round(mask_frac*dim) randomly-chosen coordinates.
    raise NotImplementedError("strong_augment")''',
'''    X = np.asarray(X, dtype=np.float64).copy()
    X = X + rng.normal(0.0, sigma, X.shape)
    n, dim = X.shape
    k = int(round(mask_frac * dim))
    if k > 0:
        for i in range(n):
            cols = rng.choice(dim, size=k, replace=False)
            X[i, cols] = 0.0
    return X''')

add('''    # TODO: copy X; for each row pick a random start and zero [start:start+length].
    raise NotImplementedError("cutout")''',
'''    X = np.asarray(X, dtype=np.float64).copy()
    n, dim = X.shape
    for i in range(n):
        start = int(rng.integers(0, dim))
        X[i, start:min(start + length, dim)] = 0.0
    return X''')

add('''    # TODO: implement the convex combination described above; return (X_mix, y_mix, lam, perm).
    raise NotImplementedError("mixup")''',
'''    X = np.asarray(X, dtype=np.float64)
    onehot = np.asarray(onehot, dtype=np.float64)
    lam = float(rng.beta(alpha, alpha))
    lam = max(lam, 1.0 - lam)
    perm = rng.permutation(X.shape[0])
    X_mix = lam * X + (1.0 - lam) * X[perm]
    y_mix = lam
…[truncated 5427 chars]
output
ssl batch1 done 17
Now the ssl loss ops:

Fill ssl loss ops

shell
python3 - <<'PY'
src=open('ssl.py').read()
R=[]
def add(o,n): R.append((o,n))

add('''    # TODO: forward value via _stable_log_softmax_np; build out via _mk(val, (logits,)); set out._backward.
    raise NotImplementedError("soft_cross_entropy")''',
'''    logp = _stable_log_softmax_np(x)
    rowloss = -(tgt * logp).sum(axis=1)
    val = float((w * rowloss).sum() / n)
    out = _mk(val, (logits,))

    def _bw():
        if logits.requires_grad:
            sm = _stable_softmax_np(x)
            tsum = tgt.sum(axis=1, keepdims=True)
            grad = (w.reshape(-1, 1) / n) * (sm * tsum - tgt)
            logits._accum(grad * out.grad)

    out._backward = _bw
    return out''')

add('''    # TODO: forward (sum of squared diffs, weighted, /N); backward through the softmax (see docstring).
    raise NotImplementedError("mse_consistency")''',
'''    s = _stable_softmax_np(x)
    diff = s - tgt
    val = float((w * (diff * diff).sum(axis=1)).sum() / n)
    out = _mk(val, (student_logits,))

    def _bw():
        if student_logits.requires_grad:
            v = (2.0 * w.reshape(-1, 1) / n) * diff
            dot = (v * s).sum(axis=1, keepdims=True)
            grad = s * (v - dot)
            student_logits._accum(grad * out.grad)

    out._backward = _bw
    return out''')

add('''    # TODO: forward (include the teacher-entropy term so KL is reported); backward as above.
    raise NotImplementedError("kl_divergence")''',
'''    logp = _stable_log_softmax_np(x)
    logt = np.lo
…[truncated 6121 chars]
output
ssl batch2 done 14
Now let me run the public checks (excluding integration/train which need more):

Run all public checks quiet

shell
cd /app && python3 run_checks.py --quiet 2>&1 | tail -20
output
----------------------------------------------------------------------
autograd_grads 77/77 | nn_forward 20/20 | optim 16/16 | fixmatch 31/31 | integration 2/2 | data 4/4
TOTAL  150/150 public checks passing
All public checks pass. Now make sure model.npz clears the held-out test threshold, and remember the grader re-checks with DIFFERENT seeds/shapes.
All 150 public checks pass. Now let me implement `train.py` and train a model. First let me write the training loop.

/app/submission/train.py

− removed
def train(lab_path, unlab_path, out_path, steps=5000, seed=0):
    dl = np.load(lab_path)
    Xl = np.asarray(dl["X"], dtype=np.float64)
    yl = np.asarray(dl["y"], dtype=np.int64).reshape(-1)
    Xu = np.asarray(np.load(unlab_path)["X"], dtype=np.float64)
    in_dim = Xl.shape[1]
    C = int(yl.max()) + 1
    # TODO: build the model + optimizer + EMA teacher (+ distribution aligner), then run the
    # FixMatch training loop (supervised CE + masked consistency with confidence-gated, optionally
    # distribution-aligned pseudo-labels), and save_checkpoint(out_path, ema.state_dict(), cfg).
    raise NotImplementedError("train")
+ added
def _predict(model, X, bs=512):
    preds = []
    for s in range(0, X.shape[0], bs):
        logits = model(X[s:s + bs]).data
        preds.append(logits.argmax(axis=1))
    return np.concatenate(preds)


def train(lab_path, unlab_path, out_path, steps=4000, seed=0,
          Xl=None, yl=None, Xu=None, val_X=None, val_y=None, verbose=True):
    if Xl is None:
        dl = np.load(lab_path)
        Xl = np.asarray(dl["X"], dtype=np.float64)
        yl = np.asarray(dl["y"], dtype=np.int64).reshape(-1)
        Xu = np.asarray(np.load(unlab_path)["X"], dtype=np.float64)
    in_dim = Xl.shape[1]
    C = int(yl.max()) + 1
    Nl, Nu = Xl.shape[0], Xu.shape[0]

    # Hyperparameters (FixMatch recipe).
    base_lr = 3e-3
    wd = 5e-4
    bs_l = 64
    bs_u = 320
    tau = 0.95
    lambda_max = 1.0
    warmup_unsup = 400          # supervised-only warmup steps
    ramp_len = 800              # linear ramp of lambda_u
    lr_warmup = 200
    ema_decay = 0.999
    weak_sigma = 0.1
    strong_sigma = 0.5
    strong_mask = 0.5

    model = MLPClassifier(in_dim, C, d_hidden=D_HIDDEN, n_layer=N_LAYER, seed=seed)
    opt = O.AdamW(model.params(), lr=base_lr, weight_decay=wd)
    ema = S.EMATeacher(model, decay=ema_decay)
    aligner = S.DistributionAligner(C, momentum=0.999)

    rng = np.random.default_rng(seed + 13)
    aug = np.random.default_rng(seed + 1234)

    for step in range(steps):
        lr = lr_at(step, steps, base_lr, lr_warmup)
        opt.lr = lr

        # supervised: wea
…[truncated 1894 chars]

contents
The file /app/submission/train.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now let me write a tuning harness that holds out part of the labeled set to estimate generalization, comparing supervised-only vs FixMatch.

Tune: supervised vs fixmatch validation

shell
cd /app/submission && cat > /tmp/tune.py <<'PY'
import sys, time
sys.path.insert(0,'/app/submission')
import numpy as np
import autograd as ag, optim as O, ssl as S
from nn import MLPClassifier
import train as TR

dl=np.load('/app/data/labeled.npz')
Xl=np.asarray(dl['X'],np.float64); yl=np.asarray(dl['y'],np.int64).reshape(-1)
Xu=np.asarray(np.load('/app/data/unlabeled.npz')['X'],np.float64)
C=int(yl.max())+1

# stratified split: hold out 6/class for val
rng=np.random.default_rng(0)
tr_idx=[]; va_idx=[]
for c in range(C):
    idx=np.where(yl==c)[0]; rng.shuffle(idx)
    va_idx+=list(idx[:6]); tr_idx+=list(idx[6:])
tr_idx=np.array(tr_idx); va_idx=np.array(va_idx)
Xtr,ytr=Xl[tr_idx],yl[tr_idx]; Xva,yva=Xl[va_idx],yl[va_idx]
print("train",Xtr.shape,"val",Xva.shape,"unlab",Xu.shape)

# supervised-only baseline
def sup_only(steps=800,seed=0):
    m=MLPClassifier(Xtr.shape[1],C,d_hidden=256,n_layer=3,seed=seed)
    opt=O.AdamW(m.params(),lr=3e-3,weight_decay=5e-4)
    rng=np.random.default_rng(seed+5)
    for st in range(steps):
        bi=rng.integers(0,Xtr.shape[0],64)
        loss=ag.cross_entropy(m(Xtr[bi]),ytr[bi])
        opt.zero_grad(); loss.backward(); O.clip_grad_norm(m.params(),5.0); opt.step()
    pred=m(Xva).data.argmax(1)
    return float((pred==yva).mean())

t0=time.time()
sup_acc=np.mean([sup_only(seed=s) for s in range(3)])
print(f"SUPERVISED-ONLY val acc = {sup_acc:.3f}  ({time.time()-t0:.1f}s)")

t0=time.time()
acc=TR.train(None,None,'/tmp/model_tune.npz',steps=3
…[truncated 195 chars]
output
train (140, 80) val (60, 80) unlab (6000, 80)
SUPERVISED-ONLY val acc = 0.478  (11.5s)
step     0 lr=0.0000 loss=2.4954 mask_rate=0.000 val_ema_acc=0.100
Output seems truncated. Let me run it to a log file in the background and monitor.

Run tuning in background

shell
nohup python3 -u /tmp/tune.py > /tmp/tune.log 2>&1 &
echo "started pid $!"
output
started pid 1503

Check tuning log after 60s

shell
sleep 60; cat /tmp/tune.log
output
<tool_use_error>Blocked: sleep 60 followed by: cat /tmp/tune.log. To wait for a condition, use Monitor with an until-loop (e.g. `until <check>; do sleep 2; done`). To wait for a command you started, use run_in_background: true. Do not chain shorter sleeps to work around this block.</tool_use_error>

Check tuning log

shell
cat /tmp/tune.log
output
train (140, 80) val (60, 80) unlab (6000, 80)

Wait for tuning to finish

shell
until grep -q "FIXMATCH val acc" /tmp/tune.log; do sleep 5; done; echo "=== DONE ==="; cat /tmp/tune.log
output
Command running in background with ID: bgrncdyjg. Output is being written to: /tmp/claude-1000/-app/8c94ab8d-0283-411e-aa02-7c4322861da2/tasks/bgrncdyjg.output. You will be notified when it completes. To check interim output, use Read on that file path.

Read current tune log

shell
sleep 1; cat /tmp/tune.log
output
train (140, 80) val (60, 80) unlab (6000, 80)
SUPERVISED-ONLY val acc = 0.478  (13.1s)
step     0 lr=0.0000 loss=2.4954 mask_rate=0.000 val_ema_acc=0.100
FixMatch is training (slow due to the per-row strong-augment loop). Let me check progress while it runs.

Check progress

shell
sleep 1; tail -5 /tmp/tune.log
output
train (140, 80) val (60, 80) unlab (6000, 80)
SUPERVISED-ONLY val acc = 0.478  (13.1s)
step     0 lr=0.0000 loss=2.4954 mask_rate=0.000 val_ema_acc=0.100
The per-row loop in `strong_augment` is the bottleneck. Let me vectorize it (preserving semantics: zero `round(mask_frac*dim)` random coords per row) for faster iteration.

Kill running tune

shell
kill 1503 2>/dev/null; pkill -f tune.py 2>/dev/null; echo killed
output
Exit code 144

/app/submission/ssl.py

contents
66	def strong_augment(X, rng, sigma: float = 0.5, mask_frac: float = 0.5) -> np.ndarray:
67	    """Strong augmentation: LARGE jitter (std ``sigma``) + then zero a random fraction ``mask_frac``
68	    of the coordinates of EACH sample (a different random subset per row). Returns a NEW array."""
69	    X = np.asarray(X, dtype=np.float64).copy()
70	    X = X + rng.normal(0.0, sigma, X.shape)
71	    n, dim = X.shape
72	    k = int(round(mask_frac * dim))
73	    if k > 0:
74	        for i in range(n):
75	            cols = rng.choice(dim, size=k, replace=False)
76	            X[i, cols] = 0.0
77	    return X
78	
79

/app/submission/ssl.py

− removed
    n, dim = X.shape
    k = int(round(mask_frac * dim))
    if k > 0:
        for i in range(n):
            cols = rng.choice(dim, size=k, replace=False)
            X[i, cols] = 0.0
    return X
+ added
    n, dim = X.shape
    k = int(round(mask_frac * dim))
    if k > 0:
        # vectorized per-row selection of k distinct coordinates to zero
        order = np.argsort(rng.random((n, dim)), axis=1)[:, :k]
        rows = np.repeat(np.arange(n), k)
        X[rows, order.reshape(-1)] = 0.0
    return X

contents
The file /app/submission/ssl.py has been updated successfully. (file state is current in your context , no need to Read it back)

Verify integration and restart tuning

shell
cd /app && python3 run_checks.py --only integration --quiet 2>&1 | tail -3
nohup python3 -u /tmp/tune.py > /tmp/tune.log 2>&1 &
echo "started $!"
output
integration 2/2
TOTAL  2/2 public checks passing
All public checks pass. Now make sure model.npz clears the held-out test threshold, and remember the grader re-checks with DIFFERENT seeds/shapes.
started 1821

Wait for tuning result

shell
until grep -q "FIXMATCH val acc" /tmp/tune.log; do sleep 5; done; echo "=== DONE ==="; cat /tmp/tune.log
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 verifier (local re-grade of the agent's own checkpoint) ===

COMPONENT CONFORMANCE SUITE: 197/197 cases passed  (all milestones pass: True)
FINAL METRIC: held-out worst-class top-1 = 0.8062  >= threshold 0.72

REWARD = 1   (1 iff every component milestone passes AND the sealed held-out metric clears its threshold)

NOTE: the in-sandbox training in the 481MB e2b box was OOM-killed (0-byte checkpoint), so the raw
in-sandbox reward was an infrastructure artifact. This reward is from a faithful LOCAL re-train of the
agent's OWN train.py (24GB, no OOM) with its own default hyperparameters, then re-graded by the real verifier.

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_744809e58b2049c9. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_744809e58b2049c9 · verifier authoritative; classifier explanatory.