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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 - Complex Implementation
EvidenceVerifier output: 'COMPONENT CONFORMANCE SUITE: 197/197 cases passed (all milestones pass: True)' and 'FINAL METRIC: held-out worst-class top-1 = 0.8478 >= threshold 0.72', 'REWARD = 1'. The component suite includes finite-difference gradient checks against reference implementations for all 50+ autograd ops, all neural network layers/cells, all optimizers/schedulers, and all FixMatch SSL components (consistency losses, confidence gates, distribution alignment, EMA updates). The final metric is scored by the grader's own reference model loading the agent's checkpoint weights, ensuring the solution generalizes properly.
Root causeThe agent successfully implemented a comprehensive numpy-only deep-learning framework (reverse-mode autodiff engine with ~50 ops each with correct analytic backward, neural network layers, optimizers, data pipeline) and the FixMatch semi-supervised learning algorithm (weak/strong augmentation, confidence-gated pseudo-labeling, masked consistency losses with proper backprop, distribution alignment, EMA teacher). The trained model cleared the sealed held-out threshold with 0.8478 accuracy, well above the 0.72 requirement, demonstrating both correctness of the framework and effective semi-supervised training.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
243 tool calls · 3 tool types · 273 steps
Agent session started, model: claude-opus-4-8 · 29 tools available · cwd: /app
I'll start by exploring the structure of the task and understanding the stub files.

List app structure

shell
ls -la && echo "---SUBMISSION---" && ls -la submission/ && echo "---DATA---" && ls -la data/
output
total 89
drwxr-xr-x  4 user user  4096 Jun 30 22:41 .
drwxr-xr-x 21 root root  4096 Jun 30 22:41 ..
-rw-r--r--  1 user user 12853 Jun 30 22:41 PROMPT.txt
-rw-r--r--  1 user user     5 Jun 30 22:41 agent.pid
-rw-r--r--  1 user user     0 Jun 30 22:41 agent.stderr
-rw-r--r--  1 user user  4497 Jun 30 22:41 agent_trajectory.jsonl
drwxr-xr-x  2 user user    60 Jun 30 22:41 data
-rw-r--r--  1 user user     0 Jun 30 22:41 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 22:41 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 22:41 .
drwxr-xr-x 4 user user  4096 Jun 30 22:41 ..
drwxr-xr-x 2 user user  4096 Jun 30 22:41 __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 22:41 .
drwxr-xr-x 4 user user    4096 Jun 30 22:41 ..
-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

Line counts of stub files

shell
wc -l submission/*.py run_checks.py test.sh 2>/dev/null
output
836 submission/autograd.py
    54 submission/data.py
   542 submission/nn.py
   162 submission/optim.py
   402 submission/ssl.py
    86 submission/train.py
  1008 run_checks.py
    25 test.sh
  3115 total
Let me read all the stub files to understand the contracts.

/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]
Now let me read the rest of the stub files.

/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 read the check runner to understand exact conventions and tolerances.

/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]
I now have a thorough understanding. Let me check the data and test.sh, then start implementing.

Inspect data shapes

shell
python3 -c "
import numpy as np
d=np.load('data/labeled.npz'); print('labeled X',d['X'].shape, 'y',d['y'].shape, 'classes', sorted(set(d['y'].tolist())))
import collections; print(collections.Counter(d['y'].tolist()))
u=np.load('data/unlabeled.npz'); print('unlabeled keys',u.files,'X',u['X'].shape)
print('X stats',d['X'].mean(),d['X'].std())
" && echo "---TEST.SH---" && cat test.sh
output
labeled X (200, 80) y (200,) classes [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Counter({7: 20, 0: 20, 9: 20, 2: 20, 6: 20, 5: 20, 1: 20, 8: 20, 4: 20, 3: 20})
unlabeled keys ['X'] X (6000, 80)
X stats -0.013586603 0.9973769
---TEST.SH---
#!/usr/bin/env bash
# Smoke test (NOT the grader): confirms the environment is wired -- numpy imports, the few labeled
# split + the unlabeled pool load, and the submission stubs are present. It does NOT check
# correctness (the stubs raise NotImplementedError until you implement them).
set -uo pipefail

python3 - <<'PY'
import numpy as np, os
lp, up = "/app/data/labeled.npz", "/app/data/unlabeled.npz"
assert os.path.exists(lp), "missing labeled.npz"
assert os.path.exists(up), "missing unlabeled.npz"
dl = np.load(lp); du = np.load(up)
print(f"labeled.npz: X{dl['X'].shape} {dl['X'].dtype}  y{dl['y'].shape}  classes={len(set(dl['y'].tolist()))}")
print(f"unlabeled.npz: X{du['X'].shape} {du['X'].dtype}  (no labels)")
for f in ("autograd.py", "nn.py", "optim.py", "data.py", "ssl.py", "train.py"):
    assert os.path.exists(f"/app/submission/{f}"), f"missing /app/submission/{f}"
assert os.path.exists("/app/run_checks.py"), "missing /app/run_checks.py"
print("submission stubs present:", sorted(os.listdir("/app/submission")))
print("numpy", np.__version__)
PY

# The visible check runner is present + runnable (it exits non-zero on the unfilled stub, which is
# expected -- the stubs raise NotImplementedError until you implement them).
python3 /app/run_checks.py -
…[truncated 102 chars]
Now I understand the full scope. Let me implement everything, starting with `autograd.py`. First the `backward` topological walk:

/app/submission/autograd.py

− removed
        TODO: implement the topological walk + seeding. (The per-op ``_backward`` closures do
        the local accumulation; here you only orchestrate the order + seed ``self.grad``.)
        """
        raise NotImplementedError("Tensor.backward")
+ added
        TODO: implement the topological walk + seeding. (The per-op ``_backward`` closures do
        the local accumulation; here you only orchestrate the order + seed ``self.grad``.)
        """
        topo: List["Tensor"] = []
        visited = set()

        def build(t: "Tensor"):
            if id(t) in visited:
                return
            visited.add(id(t))
            for p in t._parents:
                build(p)
            topo.append(t)

        build(self)
        if grad is None:
            grad = np.ones_like(self.data)
        self._accum(_as_f64(grad))
        for node in reversed(topo):
            node._backward()

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 the binary ops:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("add backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g, b.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("sub backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(-g, b.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("mul backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g * b.data, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g * a.data, b.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("div backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g / b.data, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(-g * a.data / (b.data ** 2), b.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("power backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * pf * (a.data ** (pf - 1.0)))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("maximum backward")  # TODO
+ added
    def _bw():
        g = out.grad
        am = (a.data > b.data).astype(np.float64) + 0.5 * (a.data == b.data)
        if a.requires_grad:
            a._accum(_unbroadcast(g * am, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g * (1.0 - am), b.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("minimum backward")  # TODO
+ added
    def _bw():
        g = out.grad
        am = (a.data < b.data).astype(np.float64) + 0.5 * (a.data == b.data)
        if a.requires_grad:
            a._accum(_unbroadcast(g * am, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g * (1.0 - am), b.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("where backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(np.where(c, g, 0.0), a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(np.where(c, 0.0, g), b.data.shape))

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 unary math:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("exp backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * out.data)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("log backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad / a.data)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("sqrt backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * 0.5 / out.data)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("abs backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * np.sign(a.data))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("clip backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            mask = ((a.data > lo) & (a.data < hi)).astype(np.float64)
            a._accum(out.grad * mask)

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 reductions. For sum/mean/max/min I need a helper to broadcast back:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("sum backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        g = out.grad
        if axis is not None and not keepdims:
            g = np.expand_dims(g, axis)
        a._accum(np.broadcast_to(g, a.data.shape).copy())

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("mean backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        g = out.grad
        if axis is None:
            n = a.data.size
        elif isinstance(axis, tuple):
            n = int(np.prod([a.data.shape[ax] for ax in axis]))
        else:
            n = a.data.shape[axis]
        if axis is not None and not keepdims:
            g = np.expand_dims(g, axis)
        a._accum(np.broadcast_to(g, a.data.shape).copy() / n)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("max backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        outd = out.data
        g = out.grad
        if axis is not None and not keepdims:
            outd = np.expand_dims(outd, axis)
            g = np.expand_dims(g, axis)
        mask = (a.data == outd).astype(np.float64)
        counts = mask.sum(axis=axis, keepdims=True)
        a._accum(mask * g / counts)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("min backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        outd = out.data
        g = out.grad
        if axis is not None and not keepdims:
            outd = np.expand_dims(outd, axis)
            g = np.expand_dims(g, axis)
        mask = (a.data == outd).astype(np.float64)
        counts = mask.sum(axis=axis, keepdims=True)
        a._accum(mask * g / counts)

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 shape ops:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("transpose backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        if axes is None:
            a._accum(np.transpose(out.grad))
        else:
            inv = np.argsort(axes)
            a._accum(np.transpose(out.grad, tuple(inv)))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("reshape backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad.reshape(a.data.shape))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("getitem backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        gz = np.zeros_like(a.data)
        np.add.at(gz, idx, out.grad)
        a._accum(gz)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("concat backward")  # TODO
+ added
    def _bw():
        g = out.grad
        offset = 0
        for t in ts:
            sz = t.data.shape[axis]
            if t.requires_grad:
                sl = [slice(None)] * g.ndim
                sl[axis] = slice(offset, offset + sz)
                t._accum(g[tuple(sl)])
            offset += sz

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("stack backward")  # TODO
+ added
    def _bw():
        g = out.grad
        for i, t in enumerate(ts):
            if t.requires_grad:
                sl = [slice(None)] * g.ndim
                sl[axis] = i
                t._accum(g[tuple(sl)])

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("matmul backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            da = g @ np.swapaxes(b.data, -1, -2)
            a._accum(_unbroadcast(da, a.data.shape))
        if b.requires_grad:
            db = np.swapaxes(a.data, -1, -2) @ g
            b._accum(_unbroadcast(db, b.data.shape))

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 nonlinearities:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("relu backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * (a.data > 0.0))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("leaky_relu backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * np.where(a.data > 0.0, 1.0, sl))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("sigmoid backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * s * (1.0 - s))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("tanh backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * (1.0 - t * t))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("softplus backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * (1.0 / (1.0 + np.exp(-bx))))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("silu backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * s * (1.0 + x * (1.0 - s)))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("mish backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            sig = 1.0 / (1.0 + np.exp(-x))
            a._accum(out.grad * (t + x * (1.0 - t * t) * sig))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("elu backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            grad_local = np.where(pos, 1.0, al * np.exp(np.minimum(x, 0.0)))
            a._accum(out.grad * grad_local)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("logsumexp backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        g = out.grad
        if not keepdims:
            g = np.expand_dims(g, axis)
        sm = e / s
        a._accum(g * sm)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("var backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        if axis is None:
            n = x.size
        elif isinstance(axis, tuple):
            n = int(np.prod([x.shape[ax] for ax in axis]))
        else:
            n = x.shape[axis]
        g = out.grad
        if axis is not None and not keepdims:
            g = np.expand_dims(g, axis)
        a._accum(g * (2.0 / n) * xc)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("std backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        if axis is None:
            n = x.size
        elif isinstance(axis, tuple):
            n = int(np.prod([x.shape[ax] for ax in axis]))
        else:
            n = x.shape[axis]
        g = out.grad
        if axis is not None and not keepdims:
            g = np.expand_dims(g, axis)
        a._accum(g * xc / (n * sd))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("cumsum backward")  # TODO
+ added
    def _bw():
        if not a.requires_grad:
            return
        g = out.grad
        rev = np.flip(np.cumsum(np.flip(g, axis=axis), axis=axis), axis=axis)
        a._accum(rev)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("outer backward")  # TODO
+ added
    def _bw():
        g = out.grad
        if a.requires_grad:
            a._accum(g @ b.data.reshape(-1))
        if b.requires_grad:
            b._accum(a.data.reshape(-1) @ g)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("gelu backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            pdf = np.exp(-0.5 * x * x) / np.sqrt(2.0 * np.pi)
            a._accum(out.grad * (cdf + x * pdf))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("softmax backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            g = out.grad
            a._accum(s * (g - (g * s).sum(axis=axis, keepdims=True)))

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("log_softmax backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            g = out.grad
            sm = np.exp(out.data)
            a._accum(g - sm * g.sum(axis=axis, keepdims=True))

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 losses:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("cross_entropy backward")  # TODO
+ added
    def _bw():
        if not logits.requires_grad:
            return
        sm = np.exp(logp)
        oh = np.zeros_like(sm)
        oh[np.arange(n), t] = 1.0
        logits._accum(out.grad * (sm - oh) / n)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("mse_loss backward")  # TODO
+ added
    def _bw():
        if pred.requires_grad:
            pred._accum(out.grad * 2.0 * (pred.data - tgt) / pred.data.size)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("layernorm backward")  # TODO
+ added
    def _bw():
        g = out.grad
        D = x.shape[-1]
        if gamma.requires_grad:
            axes = tuple(range(g.ndim - 1))
            gamma._accum((g * xhat).sum(axis=axes))
        if beta.requires_grad:
            axes = tuple(range(g.ndim - 1))
            beta._accum(g.sum(axis=axes))
        if a.requires_grad:
            gx = g * gamma.data
            dx = inv / D * (D * gx - gx.sum(axis=-1, keepdims=True)
                            - xhat * (gx * xhat).sum(axis=-1, keepdims=True))
            a._accum(dx)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("batchnorm backward")  # TODO
+ added
    def _bw():
        g = out.grad
        N = x.shape[0]
        if gamma.requires_grad:
            gamma._accum((g * xhat).sum(axis=0))
        if beta.requires_grad:
            beta._accum(g.sum(axis=0))
        if a.requires_grad:
            gx = g * gamma.data
            dx = inv / N * (N * gx - gx.sum(axis=0, keepdims=True)
                            - xhat * (gx * xhat).sum(axis=0, keepdims=True))
            a._accum(dx)

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

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("embedding backward")  # TODO
+ added
    def _bw():
        if not weight.requires_grad:
            return
        gz = np.zeros_like(weight.data)
        np.add.at(gz, idx, out.grad)
        weight._accum(gz)

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

/app/submission/autograd.py

− removed
        def _bw_id():
            raise NotImplementedError("dropout (eval) backward")  # TODO

        out._backward = _bw_id
        return out
    raise NotImplementedError("dropout (training) -- optional")
+ added
        def _bw_id():
            if a.requires_grad:
                a._accum(out.grad)

        out._backward = _bw_id
        return out
    r = rng if rng is not None else np.random.default_rng()
    mask = (r.random(a.data.shape) >= p).astype(np.float64) / (1.0 - p)
    out = _mk(a.data * mask, (a,), a.requires_grad)

    def _bw():
        if a.requires_grad:
            a._accum(out.grad * mask)

    out._backward = _bw
    return out

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 conv2d, maxpool2d, avgpool2d. Let me replace the three stub functions:

/app/submission/autograd.py

− removed
    TODO: implement the FORWARD and the backward. (Unlike the other ops, the forward is NOT
    pre-filled for you -- build the output, then differentiate it.)
    """
    raise NotImplementedError("conv2d")
+ added
    TODO: implement the FORWARD and the backward. (Unlike the other ops, the forward is NOT
    pre-filled for you -- build the output, then differentiate it.)
    """
    x = _ensure(x)
    weight = _ensure(weight)
    has_bias = bias is not None
    if has_bias:
        bias = _ensure(bias)
    N, Cin, H, W = x.data.shape
    Cout, Cin2, KH, KW = weight.data.shape
    s = int(stride)
    pad = int(padding)
    xp = _pad2d(x.data, pad)
    Hp, Wp = xp.shape[2], xp.shape[3]
    OH = (Hp - KH) // s + 1
    OW = (Wp - KW) // s + 1
    # im2col: (N, Cin, KH, KW, OH, OW)
    cols = np.empty((N, Cin, KH, KW, OH, OW), dtype=np.float64)
    for i in range(KH):
        for j in range(KW):
            cols[:, :, i, j, :, :] = xp[:, :, i:i + s * OH:s, j:j + s * OW:s]
    cols_r = cols.reshape(N, Cin * KH * KW, OH * OW)
    w_r = weight.data.reshape(Cout, Cin * KH * KW)
    out_data = np.einsum("oc,ncp->nop", w_r, cols_r).reshape(N, Cout, OH, OW)
    if has_bias:
        out_data = out_data + bias.data.reshape(1, Cout, 1, 1)
    rg = x.requires_grad or weight.requires_grad or (has_bias and bias.requires_grad)
    parents = (x, weight, bias) if has_bias else (x, weight)
    out = _mk(out_data, parents, rg)

    def _bw():
        g = out.grad  # (N, Cout, OH, OW)
        g_r = g.reshape(N, Cout, OH * OW)
        if has_bias and bias.requires_grad:
            bias._accum(g.sum(axis=(0, 2, 3)))
        if weight.requires_grad:
            dw_r = np.einsum("nop,ncp->oc", g_r, cols_r)
     
…[truncated 580 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)

/app/submission/autograd.py

− removed
    TODO: implement the FORWARD and the backward.
    """
    raise NotImplementedError("maxpool2d")
+ added
    TODO: implement the FORWARD and the backward.
    """
    x = _ensure(x)
    N, C, H, W = x.data.shape
    k = int(kernel)
    s = int(stride)
    OH = (H - k) // s + 1
    OW = (W - k) // s + 1
    win = np.empty((N, C, k, k, OH, OW), dtype=np.float64)
    for i in range(k):
        for j in range(k):
            win[:, :, i, j, :, :] = x.data[:, :, i:i + s * OH:s, j:j + s * OW:s]
    win_r = win.reshape(N, C, k * k, OH, OW)
    out_data = win_r.max(axis=2)
    out = _mk(out_data, (x,), x.requires_grad)

    def _bw():
        if not x.requires_grad:
            return
        g = out.grad  # (N, C, OH, OW)
        mask = (win_r == out_data[:, :, None, :, :]).astype(np.float64)
        counts = mask.sum(axis=2, keepdims=True)
        contrib = mask / counts * g[:, :, None, :, :]
        contrib = contrib.reshape(N, C, k, k, OH, OW)
        dx = np.zeros_like(x.data)
        for i in range(k):
            for j in range(k):
                dx[:, :, i:i + s * OH:s, j:j + s * OW:s] += contrib[:, :, i, j, :, :]
        x._accum(dx)

    out._backward = _bw
    return out

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

/app/submission/autograd.py

− removed
    TODO: implement the FORWARD and the backward.
    """
    raise NotImplementedError("avgpool2d")
+ added
    TODO: implement the FORWARD and the backward.
    """
    x = _ensure(x)
    N, C, H, W = x.data.shape
    k = int(kernel)
    s = int(stride)
    OH = (H - k) // s + 1
    OW = (W - k) // s + 1
    acc = np.zeros((N, C, OH, OW), dtype=np.float64)
    for i in range(k):
        for j in range(k):
            acc += x.data[:, :, i:i + s * OH:s, j:j + s * OW:s]
    out_data = acc / (k * k)
    out = _mk(out_data, (x,), x.requires_grad)

    def _bw():
        if not x.requires_grad:
            return
        g = out.grad / (k * k)
        dx = np.zeros_like(x.data)
        for i in range(k):
            for j in range(k):
                dx[:, :, i:i + s * OH:s, j:j + s * OW:s] += g
        x._accum(dx)

    out._backward = _bw
    return out

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 let me implement nn.py forwards. Let me do them all:

/app/submission/nn.py

− removed
        # TODO: matmul x@weight then add bias (if present). Use ag.matmul / ag.add.
        raise NotImplementedError("Linear.forward")
+ added
        out = ag.matmul(x, self.weight)
        if self.bias is not None:
            out = ag.add(out, self.bias)
        return out

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

/app/submission/nn.py

− removed
        # TODO: return ag.embedding(self.weight, idx)
        raise NotImplementedError("Embedding.forward")
+ added
        return ag.embedding(self.weight, idx)

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

/app/submission/nn.py

− removed
        # TODO: return ag.layernorm(x, self.gamma, self.beta, self.eps)
        raise NotImplementedError("LayerNorm.forward")
+ added
        return ag.layernorm(x, self.gamma, self.beta, self.eps)

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

/app/submission/nn.py

− removed
        # TODO: ms = mean(x*x, -1, keepdims); inv = (ms+eps)**-0.5; return x*inv*gamma  (autograd ops)
        raise NotImplementedError("RMSNorm.forward")
+ added
        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)

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

/app/submission/nn.py

− removed
        # TODO: g = ag.silu(self.w_gate(x)); u = self.w_up(x); return self.w_down(ag.mul(g, u))
        raise NotImplementedError("SwiGLU.forward")
+ added
        g = ag.silu(self.w_gate(x))
        u = self.w_up(x)
        return self.w_down(ag.mul(g, u))

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

/app/submission/nn.py

− removed
        # TODO: return ag.batchnorm(x, self.gamma, self.beta, self.eps)
        raise NotImplementedError("BatchNorm1d.forward")
+ added
        return ag.batchnorm(x, self.gamma, self.beta, self.eps)

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

/app/submission/nn.py

− removed
        # TODO: return ag.dropout(x, self.p, training, rng)
        raise NotImplementedError("Dropout.forward")
+ added
        return ag.dropout(x, self.p, training, rng)

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

/app/submission/nn.py

− removed
        # TODO: return ag.conv2d(x, self.weight, self.bias, self.stride, self.padding)
        raise NotImplementedError("Conv2d.forward")
+ added
        return ag.conv2d(x, self.weight, self.bias, self.stride, self.padding)

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

/app/submission/nn.py

− removed
        # TODO: return ag.maxpool2d(x, self.kernel, self.stride)
        raise NotImplementedError("MaxPool2d.forward")
+ added
        return ag.maxpool2d(x, self.kernel, self.stride)

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

/app/submission/nn.py

− removed
        # TODO: return ag.avgpool2d(x, self.kernel, self.stride)
        raise NotImplementedError("AvgPool2d.forward")
+ added
        return ag.avgpool2d(x, self.kernel, self.stride)

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

/app/submission/nn.py

− removed
        # TODO: implement causal multi-head self-attention as described in the docstring.
        raise NotImplementedError("MultiHeadSelfAttention.forward")
+ added
        B, Tn, _ = x.shape
        H, dh = self.n_head, self.d_head
        qkv = self.qkv(x)  # (B, T, 3*d_model)
        qkv = ag.reshape(qkv, (B, Tn, 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]
        kt = ag.transpose(k, (0, 1, 3, 2))  # (B, H, dh, T)
        scores = ag.mul(ag.matmul(q, kt), 1.0 / np.sqrt(dh))  # (B, H, T, T)
        mask = np.triu(np.ones((Tn, Tn), dtype=np.float64), k=1) * (-1e9)
        scores = ag.add(scores, Tensor(mask.reshape(1, 1, Tn, Tn)))
        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, Tn, self.d_model))
        return self.proj(out)

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

/app/submission/nn.py

− removed
        # TODO: fc2(gelu(fc1(x)))
        raise NotImplementedError("MLP.forward")
+ added
        return self.fc2(ag.gelu(self.fc1(x)))

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

/app/submission/nn.py

− removed
        # TODO: pre-norm residual wiring (see docstring).
        raise NotImplementedError("TransformerBlock.forward")
+ added
        x = ag.add(x, self.attn(self.ln1(x)))
        x = ag.add(x, self.mlp(self.ln2(x)))
        return x

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

/app/submission/nn.py

− removed
        # TODO: tanh(x@W_ih + b_ih + h@W_hh + b_hh)
        raise NotImplementedError("RNNCell.forward")
+ added
        pre = ag.add(ag.add(ag.matmul(x, self.W_ih), self.b_ih),
                     ag.add(ag.matmul(h, self.W_hh), self.b_hh))
        return ag.tanh(pre)

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

/app/submission/nn.py

− removed
        # TODO: implement the LSTM cell update; return (h_new, c_new).
        raise NotImplementedError("LSTMCell.forward")
+ added
        h, c = state
        H = self.hidden
        z = ag.add(ag.add(ag.matmul(x, self.W_ih), self.b_ih),
                   ag.add(ag.matmul(h, self.W_hh), self.b_hh))
        i = ag.sigmoid(z[:, 0 * H:1 * H])
        f = ag.sigmoid(z[:, 1 * H:2 * H])
        g = ag.tanh(z[:, 2 * H:3 * H])
        o = ag.sigmoid(z[:, 3 * H:4 * H])
        c_new = ag.add(ag.mul(f, c), ag.mul(i, g))
        h_new = ag.mul(o, ag.tanh(c_new))
        return h_new, c_new

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

/app/submission/nn.py

− removed
        # TODO: implement the GRU cell update; return h_new.
        raise NotImplementedError("GRUCell.forward")
+ added
        H = self.hidden
        gi = ag.add(ag.matmul(x, self.W_ih), self.b_ih)
        gh = ag.add(ag.matmul(h, self.W_hh), self.b_hh)
        r = ag.sigmoid(ag.add(gi[:, 0 * H:1 * H], gh[:, 0 * H:1 * H]))
        z = ag.sigmoid(ag.add(gi[:, 1 * H:2 * H], gh[:, 1 * H:2 * H]))
        n = ag.tanh(ag.add(gi[:, 2 * H:3 * H], ag.mul(r, gh[:, 2 * H:3 * H])))
        h_new = ag.add(ag.mul(ag.sub(1.0, z), n), ag.mul(z, h))
        return h_new

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

/app/submission/nn.py

− removed
        # TODO: relu(layernorm(linear(x))) -- compose self.fc, self.ln and ag.relu.
        raise NotImplementedError("HiddenBlock.forward")
+ added
        return ag.relu(self.ln(self.fc(x)))

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

/app/submission/nn.py

− removed
        # TODO: h = Tensor(X) if X is a raw array; for blk in self.layers: h = blk(h);
        #       return self.head(h)
        raise NotImplementedError("MLPClassifier.forward")
+ added
        h = X if isinstance(X, Tensor) else Tensor(np.asarray(X, dtype=np.float64))
        for blk in self.layers:
            h = blk(h)
        return self.head(h)

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

/app/submission/nn.py

− removed
        # TODO: implement the conv->relu->maxpool x2 -> flatten -> fc pipeline (see docstring).
        #       Wrap a raw ndarray x in a Tensor first; reshape with the batch size N as dim 0.
        raise NotImplementedError("CNNClassifier.forward")
+ added
        h = x if isinstance(x, Tensor) else Tensor(np.asarray(x, dtype=np.float64))
        N = h.shape[0]
        h = ag.maxpool2d(ag.relu(self.conv1(h)), 2, 2)
        h = ag.maxpool2d(ag.relu(self.conv2(h)), 2, 2)
        h = ag.reshape(h, (N, self.feat))
        return self.fc(h)

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

/app/submission/nn.py

− removed
        # TODO: embed idx, loop the cell over time from a zero state, classify the final hidden.
        raise NotImplementedError("SeqClassifier.forward")
+ added
        idx = np.asarray(idx)
        N, T = idx.shape
        emb = self.embed(idx)  # (N, T, d_model)
        h = Tensor(np.zeros((N, self.hidden)))
        if self.cell_kind == "lstm":
            c = Tensor(np.zeros((N, self.hidden)))
            for t in range(T):
                h, c = self.cell(emb[:, t, :], (h, c))
        else:
            for t in range(T):
                h = self.cell(emb[:, t, :], h)
        return self.fc(h)

contents
The file /app/submission/nn.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now let me run the autograd and nn_forward checks before continuing:

Run autograd grad checks

shell
python3 run_checks.py --only autograd_grads 2>&1 | tail -25
output
grad/cross_entropy                   OK  
  grad/embedding                       OK  
  grad/nn.Linear_x                     OK  
  grad/nn.RMSNorm_x                    OK  
  grad/nn.SwiGLU_x                     OK  
  grad/nn.LayerNorm_x                  OK  
  grad/nn.BatchNorm1d_x                OK  
  grad/nn.HiddenBlock_x                OK  
  grad/nn.MLP_x                        OK  
  grad/nn.MHA_x                        OK  
  grad/nn.Conv2d_x                     OK  
  grad/nn.MaxPool2d_x                  OK  
  grad/nn.AvgPool2d_x                  OK  
  grad/nn.RNNCell_x                    OK  
  grad/nn.LSTMCell_x                   OK  
  grad/nn.GRUCell_x                    OK  
  grad/clf_head.bias                   OK  
  grad/clf_layers.0.fc.weight          OK  
  grad/clf_layers.1.ln.gamma           OK  
  grad/clf_layers.0.fc.bias            OK  

----------------------------------------------------------------------
autograd_grads 77/77
TOTAL  77/77 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 autograd grad checks pass. Now nn_forward and optim:

Run nn_forward checks

shell
python3 run_checks.py --only nn_forward 2>&1 | tail -8
output
fwd/MLPClassifier_shape              OK  
  fwd/CNN_shape                        OK  
  fwd/Seq_shape                        OK  

----------------------------------------------------------------------
nn_forward 20/20
TOTAL  20/20 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.
Now optim.py. Let me implement all the optimizers and schedulers:

/app/submission/optim.py

− removed
    def step(self):
        # TODO: SGD(+momentum, +coupled weight decay, +optional Nesterov) update.
        raise NotImplementedError("SGD.step")
+ added
    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            v = self.momentum * self._v[i] + g
            self._v[i] = v
            upd = (g + self.momentum * v) if self.nesterov else v
            p.data -= self.lr * upd

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

/app/submission/optim.py

− removed
    def step(self):
        # TODO: Adagrad update (accumulate squared grads).
        raise NotImplementedError("Adagrad.step")
+ added
    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)

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

/app/submission/optim.py

− removed
    def step(self):
        # TODO: RMSprop update (EMA of squared grads).
        raise NotImplementedError("RMSprop.step")
+ added
    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)

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

/app/submission/optim.py

− removed
    def step(self):
        # TODO: Adam update with bias correction + COUPLED (L2) weight decay.
        raise NotImplementedError("Adam.step")
+ added
    def step(self):
        self.t += 1
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._m[i] = self.b1 * self._m[i] + (1 - self.b1) * g
            self._v[i] = self.b2 * self._v[i] + (1 - self.b2) * (g * g)
            mhat = self._m[i] / (1 - self.b1 ** self.t)
            vhat = self._v[i] / (1 - self.b2 ** self.t)
            p.data -= self.lr * mhat / (np.sqrt(vhat) + self.eps)

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

/app/submission/optim.py

− removed
    def step(self):
        # TODO: AdamW update with bias correction + DECOUPLED weight decay.
        raise NotImplementedError("AdamW.step")
+ added
    def step(self):
        self.t += 1
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad
            self._m[i] = self.b1 * self._m[i] + (1 - self.b1) * g
            self._v[i] = self.b2 * self._v[i] + (1 - self.b2) * (g * g)
            mhat = self._m[i] / (1 - self.b1 ** self.t)
            vhat = self._v[i] / (1 - self.b2 ** self.t)
            p.data -= self.lr * (mhat / (np.sqrt(vhat) + self.eps) + self.weight_decay * p.data)

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

/app/submission/optim.py

− removed
    def step(self):
        # TODO: Lion update (sign of interpolated momentum; momentum updated AFTER the step).
        raise NotImplementedError("Lion.step")
+ added
    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad
            upd = np.sign(self.b1 * self._m[i] + (1 - self.b1) * g)
            p.data -= self.lr * (upd + self.weight_decay * p.data)
            self._m[i] = self.b2 * self._m[i] + (1 - self.b2) * g

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

/app/submission/optim.py

− removed
    # TODO: compute the global L2 norm over all param grads; scale in place if it exceeds max_norm.
    raise NotImplementedError("clip_grad_norm")
+ added
    total = math.sqrt(sum(float((p.grad ** 2).sum()) for p in params if p.grad is not None))
    if total > max_norm:
        sc = max_norm / (total + 1e-6)
        for p in params:
            if p.grad is not None:
                p.grad = p.grad * sc
    return total

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

/app/submission/optim.py

− removed
    # TODO
    raise NotImplementedError("cosine_lr")
+ added
    if warmup > 0 and step < warmup:
        return base_lr * (step + 1) / warmup
    prog = min(1.0, max(0.0, (step - warmup) / max(1, total - warmup)))
    return min_lr + 0.5 * (base_lr - min_lr) * (1 + math.cos(math.pi * prog))

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

/app/submission/optim.py

− removed
    # TODO
    raise NotImplementedError("step_lr")
+ added
    return base_lr * gamma ** (step // step_size)

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

/app/submission/optim.py

− removed
    # TODO
    raise NotImplementedError("exponential_lr")
+ added
    return base_lr * gamma ** step

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

/app/submission/optim.py

− removed
    # TODO
    raise NotImplementedError("warmup_lr")
+ added
    if step < warmup:
        return base_lr * (step + 1) / warmup
    return base_lr

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

Run optim checks

shell
python3 run_checks.py --only optim 2>&1 | tail -25
output
[optim]  16/16
  optim/SGD_1step                      OK    (max_abs=0.0e+00)
  optim/SGD_momentum_5step             OK    (max_abs=0.0e+00)
  optim/SGD_nesterov_5step             OK    (max_abs=0.0e+00)
  optim/Adagrad_5step                  OK    (max_abs=0.0e+00)
  optim/RMSprop_5step                  OK    (max_abs=0.0e+00)
  optim/Adam_1step                     OK    (max_abs=0.0e+00)
  optim/Adam_10step_wd                 OK    (max_abs=0.0e+00)
  optim/AdamW_1step                    OK    (max_abs=0.0e+00)
  optim/AdamW_10step_wd                OK    (max_abs=0.0e+00)
  optim/Lion_5step                     OK    (max_abs=0.0e+00)
  optim/clip_grad_norm_clips           OK    (max_abs=0.0e+00)
  optim/clip_grad_norm_noop            OK    (max_abs=0.0e+00)
  optim/sched_cosine                   OK    (max_abs=0.0e+00)
  optim/sched_warmup                   OK    (max_abs=0.0e+00)
  optim/sched_step                     OK    (max_abs=0.0e+00)
  optim/sched_exponential              OK    (max_abs=0.0e+00)

----------------------------------------------------------------------
optim 16/16
TOTAL  16/16 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.
Now data.py:

/app/submission/data.py

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


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 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")
+ added
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.files else None
    return X, y


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):
    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):
    idx = np.asarray(idx, dtype=np.int64)
    Xb = np.asarray(X[idx], dtype=np.float64)
    yb = np.asarray(y[idx], dtype=np.int64) if y is not None else None
    return Xb, yb, idx

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

/app/submission/data.py

− removed
    # TODO: build per-class templates, pick labels, return template[y] + noise and the labels.
    raise NotImplementedError("make_image_dataset")
+ added
    rng = np.random.default_rng(seed)
    templates = rng.standard_normal((n_classes, 1, img, img))
    y = rng.integers(0, n_classes, size=n)
    X = templates[y] + rng.standard_normal((n, 1, img, img)) * 0.5
    return np.asarray(X, dtype=np.float64), np.asarray(y, dtype=np.int64)

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

/app/submission/data.py

− removed
    # TODO: sample (n, T) token ids in [0, vocab); label = (row sum) % n_classes.
    raise NotImplementedError("make_seq_dataset")
+ added
    rng = np.random.default_rng(seed)
    X = rng.integers(0, vocab, size=(n, T))
    y = X.sum(axis=1) % n_classes
    return np.asarray(X, dtype=np.int64), np.asarray(y, dtype=np.int64)

contents
The file /app/submission/data.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now the big one , ssl.py. Let me implement augmentation, gates, alignment, ramps, and the differentiable losses. Starting with augmentation:

/app/submission/ssl.py

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

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

/app/submission/ssl.py

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

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

/app/submission/ssl.py

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

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

/app/submission/ssl.py

− removed
    # TODO: implement the convex combination described above; return (X_mix, y_mix, lam, perm).
    raise NotImplementedError("mixup")
+ added
    X = np.asarray(X, dtype=np.float64)
    onehot = np.asarray(onehot, dtype=np.float64)
    lam = float(rng.beta(alpha, alpha))
    lam = builtins_max(lam, 1.0 - lam)
    n = X.shape[0]
    perm = rng.permutation(n)
    X_mix = lam * X + (1.0 - lam) * X[perm]
    y_mix = lam * onehot + (1.0 - lam) * onehot[perm]
    return X_mix, y_mix, lam, perm

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

/app/submission/ssl.py

− removed
    # TODO: stack to (K, M, ...), swap the leading block axis with K over full blocks, return list.
    raise NotImplementedError("interleave")
+ added
    arrs = [np.asarray(a) for a in arrays]
    K = len(arrs)
    stacked = np.stack(arrs, axis=0)  # (K, M, *rest)
    M = stacked.shape[1]
    rest = stacked.shape[2:]
    nb = M // batch_size
    a = stacked.reshape((K, nb, batch_size) + rest)
    b = a.swapaxes(0, 1)  # (nb, K, batch_size, *rest)
    out = b.reshape((K, M) + rest)
    return [out[i] for i in range(K)]

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

/app/submission/ssl.py

− removed
    # TODO: invert the interleave permutation.
    raise NotImplementedError("de_interleave")
+ added
    arrs = [np.asarray(a) for a in arrays]
    K = len(arrs)
    stacked = np.stack(arrs, axis=0)  # (K, M, *rest)
    M = stacked.shape[1]
    rest = stacked.shape[2:]
    nb = M // batch_size
    c = stacked.reshape((nb, K, batch_size) + rest)
    d = c.swapaxes(0, 1)  # (K, nb, batch_size, *rest)
    out = d.reshape((K, M) + rest)
    return [out[i] for i in range(K)]

contents
The file /app/submission/ssl.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now the gate/sharpen/EMAScalar/DistributionAligner/FlexMatch/ramps/complement:

/app/submission/ssl.py

− removed
    # TODO: compute hard/conf/mask/onehot as above.
    raise NotImplementedError("pseudo_label")
+ added
    weak_probs = np.asarray(weak_probs, dtype=np.float64)
    n, c = weak_probs.shape
    hard = weak_probs.argmax(axis=1)
    conf = weak_probs.max(axis=1)
    mask = (conf >= tau).astype(np.float64)
    onehot = np.zeros((n, c), dtype=np.float64)
    onehot[np.arange(n), hard] = 1.0
    return onehot, mask, hard

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

/app/submission/ssl.py

− removed
    # TODO: return (probs.max(axis=1) >= tau).astype(float)
    raise NotImplementedError("confidence_mask")
+ added
    probs = np.asarray(probs, dtype=np.float64)
    return (probs.max(axis=1) >= tau).astype(np.float64)

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

/app/submission/ssl.py

− removed
    # TODO: pw = probs ** (1/temperature); return pw / pw.sum(axis=1, keepdims=True)
    raise NotImplementedError("sharpen")
+ added
    probs = np.asarray(probs, dtype=np.float64)
    pw = probs ** (1.0 / temperature)
    return pw / pw.sum(axis=1, keepdims=True)

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

/app/submission/ssl.py

− removed
        # TODO: update self.value with the EMA recursion and return it.
        raise NotImplementedError("EMAScalar.update")
+ added
        self.value = self.decay * self.value + (1.0 - self.decay) * float(new)
        return self.value

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

/app/submission/ssl.py

− removed
        # TODO: update self.running, rescale by prior/(running+1e-6), renormalize rows, return.
        raise NotImplementedError("DistributionAligner.align")
+ added
        weak_probs = np.asarray(weak_probs, dtype=np.float64)
        self.running = self.momentum * self.running + (1.0 - self.momentum) * weak_probs.mean(axis=0)
        aligned = weak_probs * (self.prior / (self.running + 1e-6))
        aligned = aligned / aligned.sum(axis=1, keepdims=True)
        return aligned

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

/app/submission/ssl.py

− removed
        # TODO: compute sigma (per-class confident-argmax counts), set self.sigma, return beta*tau
        # with denom = max(sigma.max(), C - sigma.sum()) (guard against 0).
        raise NotImplementedError("FlexMatchThresholder.update")

    def flex_mask(self, weak_probs) -> np.ndarray:
        # TODO: thr = self.update(weak_probs); return (max prob per row >= thr[argmax]) as 0/1 float.
        raise NotImplementedError("FlexMatchThresholder.flex_mask")
+ added
        weak_probs = np.asarray(weak_probs, dtype=np.float64)
        hard = weak_probs.argmax(axis=1)
        conf = weak_probs.max(axis=1)
        adm = conf >= self.tau
        sigma = np.array([float(np.sum(adm & (hard == c))) for c in range(self.C)], dtype=np.float64)
        self.sigma = sigma
        denom = builtins_max(float(sigma.max()), float(self.C - sigma.sum()))
        denom = denom if denom > 0 else 1.0
        return (sigma / denom) * self.tau

    def flex_mask(self, weak_probs) -> np.ndarray:
        weak_probs = np.asarray(weak_probs, dtype=np.float64)
        thr = self.update(weak_probs)
        hard = weak_probs.argmax(axis=1)
        conf = weak_probs.max(axis=1)
        return (conf >= thr[hard]).astype(np.float64)

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

/app/submission/ssl.py

− removed
    # TODO: clip(step/length, 0, 1) (handle length<=0 -> 1.0).
    raise NotImplementedError("linear_rampup")
+ added
    if length <= 0:
        return 1.0
    return float(np.clip(step / length, 0.0, 1.0))

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

/app/submission/ssl.py

− removed
    # TODO: per the docstring (1.0 once step>=length).
    raise NotImplementedError("cosine_rampup")
+ added
    if length <= 0:
        return 1.0
    x = float(np.clip(step / length, 0.0, 1.0))
    return 0.5 * (1.0 - np.cos(np.pi * 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)

/app/submission/ssl.py

− removed
    # TODO: per the docstring.
    raise NotImplementedError("exp_rampup")
+ added
    if length <= 0:
        return 1.0
    x = float(np.clip(step / length, 0.0, 1.0))
    return float(np.exp(-5.0 * (1.0 - x) ** 2))

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

/app/submission/ssl.py

− removed
    # TODO: build the (N,C) complementary one-hot on argmin for confident rows only.
    raise NotImplementedError("complement_distribution")
+ added
    weak_probs = np.asarray(weak_probs, dtype=np.float64)
    n, c = weak_probs.shape
    conf = weak_probs.max(axis=1)
    least = weak_probs.argmin(axis=1)
    sel = conf >= tau
    comp = np.zeros((n, c), dtype=np.float64)
    comp[np.arange(n)[sel], least[sel]] = 1.0
    return comp

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

/app/submission/ssl.py

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

    def _bw():
        if not logits.requires_grad:
            return
        sm = np.exp(logp)
        tsum = tgt.sum(axis=1, keepdims=True)
        grad = (w[:, None] / n) * (sm * tsum - tgt)
        logits._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward (sum of squared diffs, weighted, /N); backward through the softmax (see docstring).
    raise NotImplementedError("mse_consistency")
+ added
    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 not student_logits.requires_grad:
            return
        v = (2.0 * w[:, None] / n) * diff
        grad = s * (v - (v * s).sum(axis=1, keepdims=True))
        student_logits._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward (include the teacher-entropy term so KL is reported); backward as above.
    raise NotImplementedError("kl_divergence")
+ added
    logp = _stable_log_softmax_np(x)
    log_t = np.log(np.clip(tgt, 1e-12, None))
    per_row = (tgt * (log_t - logp)).sum(axis=1)
    val = float((w * per_row).sum() / n)
    out = _mk(val, (student_logits,))

    def _bw():
        if not student_logits.requires_grad:
            return
        sm = np.exp(logp)
        tsum = tgt.sum(axis=1, keepdims=True)
        grad = (w[:, None] / n) * (sm * tsum - tgt)
        student_logits._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward mean entropy; backward per the docstring.
    raise NotImplementedError("entropy_loss")
+ added
    logp = _stable_log_softmax_np(x)
    p = np.exp(logp)
    H = -(p * logp).sum(axis=1)  # (N,)
    val = float(H.sum() / n)
    out = _mk(val, (logits,))

    def _bw():
        if not logits.requires_grad:
            return
        grad = (1.0 / n) * p * (-logp - H[:, None])
        logits._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward (-H of the batch marginal); backward per the docstring.
    raise NotImplementedError("class_balance_loss")
+ added
    p = _stable_softmax_np(x)
    pbar = p.mean(axis=0)  # (C,)
    val = float((pbar * np.log(np.clip(pbar, 1e-12, None))).sum())
    out = _mk(val, (logits,))

    def _bw():
        if not logits.requires_grad:
            return
        a = 1.0 + np.log(np.clip(pbar, 1e-12, None))  # (C,)
        ap = (p * a[None, :]).sum(axis=1, keepdims=True)
        grad = (1.0 / n) * p * (a[None, :] - ap)
        logits._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: stable sigmoid-BCE forward via _mk(val, (z,)); backward (w/N)*(sigmoid(z)-t).
    raise NotImplementedError("bce_consistency")
+ added
    per_elem = np.maximum(x, 0.0) - x * t + np.log1p(np.exp(-np.abs(x)))
    val = float((w * per_elem.sum(axis=1)).sum() / n)
    out = _mk(val, (z,))

    def _bw():
        if not z.requires_grad:
            return
        s = 1.0 / (1.0 + np.exp(-x))
        grad = (w[:, None] / n) * (s - t)
        z._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward sum-squared-diff averaged over N; backward (2w/N)*(x-t).
    raise NotImplementedError("pi_consistency")
+ added
    diff = x - t
    val = float((w * (diff * diff).sum(axis=1)).sum() / n)
    out = _mk(val, (z,))

    def _bw():
        if not z.requires_grad:
            return
        grad = (2.0 * w[:, None] / n) * diff
        z._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward via _stable_log_softmax_np; backward through softmax per the docstring.
    raise NotImplementedError("focal_consistency")
+ added
    logp = _stable_log_softmax_np(x)
    p = np.exp(logp)
    neglog = -logp
    om = 1.0 - p
    om_g = om ** gm
    phi = t * om_g * neglog
    val = float((w * phi.sum(axis=1)).sum() / n)
    out = _mk(val, (z,))

    def _bw():
        if not z.requires_grad:
            return
        om_gm1 = om ** (gm - 1.0)
        u = t * (-gm * om_gm1 * neglog - om_g / p)
        up = (u * p).sum(axis=1, keepdims=True)
        grad = (w[:, None] / n) * p * (u - up)
        z._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward JS (clip probs to 1e-12 before log); backward through softmax per the docstring.
    raise NotImplementedError("js_divergence")
+ added
    p = _stable_softmax_np(x)
    m = 0.5 * (p + t)
    pc = np.clip(p, 1e-12, None)
    tc = np.clip(t, 1e-12, None)
    mc = np.clip(m, 1e-12, None)
    js = 0.5 * (p * (np.log(pc) - np.log(mc))).sum(axis=1) \
        + 0.5 * (t * (np.log(tc) - np.log(mc))).sum(axis=1)
    val = float((w * js).sum() / n)
    out = _mk(val, (z,))

    def _bw():
        if not z.requires_grad:
            return
        u = (w[:, None] / n) * 0.5 * (np.log(pc) - np.log(mc))
        up = (u * p).sum(axis=1, keepdims=True)
        grad = p * (u - up)
        z._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: forward -(comp*log(1-p)) (clip 1-p to 1e-12); backward through softmax per the docstring.
    raise NotImplementedError("negative_consistency")
+ added
    p = _stable_softmax_np(x)
    om = np.clip(1.0 - p, 1e-12, None)
    val = float(-(w * (comp * np.log(om)).sum(axis=1)).sum() / n)
    out = _mk(val, (z,))

    def _bw():
        if not z.requires_grad:
            return
        u = comp / om
        up = (u * p).sum(axis=1, keepdims=True)
        grad = (w[:, None] / n) * p * (u - up)
        z._accum(out.grad * grad)

    out._backward = _bw
    return out

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

/app/submission/ssl.py

− removed
    # TODO: onehot, mask = pseudo_label(...); loss = soft_cross_entropy(...); scale by lambda_u.
    raise NotImplementedError("consistency_loss")
+ added
    weak_probs = np.asarray(weak_probs, dtype=np.float64)
    onehot, mask, _ = pseudo_label(weak_probs, tau)
    loss = soft_cross_entropy(strong_logits, onehot, weight=mask)
    if lambda_u != 1.0:
        loss = ag.mul(loss, lambda_u)
    mask_rate = float(mask.mean())
    return loss, mask_rate

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

/app/submission/ssl.py

− removed
    # TODO: sup = ag.cross_entropy(...); cons, mr = consistency_loss(...); return (ag.add(sup, cons), mr).
    raise NotImplementedError("fixmatch_loss")
+ added
    sup = ag.cross_entropy(sup_logits, sup_y)
    cons, mr = consistency_loss(strong_logits, weak_probs, tau, lambda_u=lambda_u)
    return ag.add(sup, cons), mr

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

/app/submission/ssl.py

− removed
    def update(self, model):
        # TODO: for each named param, shadow <- decay*shadow + (1-decay)*param.data (in place).
        raise NotImplementedError("EMATeacher.update")

    def copy_to(self, model):
        # TODO: write self.shadow[k] into each model param's data.
        raise NotImplementedError("EMATeacher.copy_to")
+ added
    def update(self, model):
        d = self.decay
        for k, v in model.named_params().items():
            self.shadow[k] = d * self.shadow[k] + (1.0 - d) * v.data

    def copy_to(self, model):
        for k, v in model.named_params().items():
            v.data[...] = self.shadow[k]

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

Run fixmatch checks

shell
python3 run_checks.py --only fixmatch 2>&1 | tail -40
output
[fixmatch]  31/31
  fixmatch/sce_bwd_onehot              OK    (max_abs=2.72e-11)
  fixmatch/sce_bwd_soft                OK    (max_abs=3.07e-11)
  fixmatch/mse_consistency_bwd         OK    (max_abs=2.91e-12)
  fixmatch/kl_divergence_bwd           OK    (max_abs=1.02e-11)
  fixmatch/entropy_loss_bwd            OK    (max_abs=1.93e-11)
  fixmatch/class_balance_bwd           OK    (max_abs=2.09e-11)
  fixmatch/bce_consistency_bwd         OK    (max_abs=9.43e-12)
  fixmatch/pi_consistency_bwd          OK    (max_abs=8.00e-11)
  fixmatch/focal_bwd_onehot            OK    (max_abs=8.93e-12)
  fixmatch/focal_bwd_soft              OK    (max_abs=1.15e-11)
  fixmatch/js_divergence_bwd           OK    (max_abs=1.39e-12)
  fixmatch/negative_consistency_bwd    OK    (max_abs=7.06e-12)
  fixmatch/flexmatch_threshold         OK  
  fixmatch/rampup_schedules            OK  
  fixmatch/complement_distribution     OK  
  fixmatch/cons_bwd_tau0.3             OK    (max_abs=2.06e-11)
  fixmatch/cons_bwd_tau0.5             OK    (max_abs=0.00e+00)
  fixmatch/cons_mask_all_zero          OK  
  fixmatch/pseudo_label_gate           OK  
  fixmatch/pseudo_label_boundary       OK  
  fixmatch/confidence_mask             OK  
  fixmatch/sharpen_T0.5                OK  
  fixmatch/sharpen_T2.0                OK  
  fixmatch/sharpen_identity            OK  
  fixmatch/mixup_convex                OK    (lam=0.904)
  fixmatch/interleave_roundtrip        OK  
  fixmatch/da_recursion                OK  
 
…[truncated 443 chars]
All 31 fixmatch checks pass. Let me run the full suite:

Run full check suite

shell
python3 run_checks.py --quiet 2>&1 | tail -6
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 write the FixMatch training loop in train.py. First let me understand the data better to design the training:

Inspect data structure

shell
python3 -c "
import numpy as np
d=np.load('data/labeled.npz'); X,y=d['X'],d['y']
u=np.load('data/unlabeled.npz')['X']
# quick supervised-only baseline idea: check class separability via nearest centroid on raw 80-dim
from collections import Counter
print('labeled', X.shape, 'unlabeled', u.shape)
# PCA to see signal subspace
allX=np.vstack([X,u])
allX=allX-allX.mean(0)
cov=allX.T@allX/len(allX)
w,_=np.linalg.eigh(cov)
print('top eigs', w[-12:][::-1])
"
output
labeled (200, 80) unlabeled (6000, 80)
top eigs [1.3897966 1.3660743 1.3534957 1.3339317 1.3317931 1.3191792 1.3178654
 1.3113981 1.3056706 1.2844936 1.2825733 1.269397 ]
All checks pass. Now let me write the FixMatch training loop:

/app/submission/train.py

− removed
    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
    in_dim = Xl.shape[1]
    C = int(yl.max()) + 1
    Nl = Xl.shape[0]
    Nu = Xu.shape[0]

    rng = np.random.default_rng(seed)
    aug = np.random.default_rng(seed + 12345)

    model = MLPClassifier(in_dim, C, d_hidden=D_HIDDEN, n_layer=N_LAYER, seed=seed)
    opt = O.AdamW(model.params(), lr=3e-3, betas=(0.9, 0.999), weight_decay=5e-4)
    ema = S.EMATeacher(model, decay=0.999)
    aligner = S.DistributionAligner(C, momentum=0.999)

    tau = 0.95
    lambda_u_max = 1.0
    base_lr = 3e-3
    warmup = 200
    rampup_len = max(1, steps // 2)
    lab_bs = 64
    unlab_bs = 384

    def sample(n, bs):
        return rng.integers(0, n, size=bs)

    for step in range(steps):
        lr = lr_at(step, steps, base_lr, warmup)
        opt.lr = lr
        lam = lambda_u_max * S.linear_rampup(step, rampup_len)

        # supervised: weak-augmented labeled batch
        li = sample(Nl, lab_bs)
        Xl_w = S.weak_augment(Xl[li], aug, sigma=0.1)
        sup_logits = model(Xl_w)
        sup_loss = ag.cross_entropy(sup_logits, yl[li])

        opt.zero_grad()
        if lam > 0.0:
            ui = sample(Nu, unlab_bs)
            Xu_b = Xu[ui]
            # weak view -> detached pseudo-labels (distribution aligned)
            wp = S._stable_softmax_np(np.asarray(model(S.weak_augment(Xu_b, aug, sigma=0.1)).data,
                                                 dtype=np.float64))
            wp = aligner.align(wp)
            strong_logits = model(S.strong_augment(Xu_b, aug, sigma=
…[truncated 811 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)
Let me build a quick proxy-evaluation harness to verify FixMatch generalizes before committing to the full run. I'll hold out part of the labeled set:

Proxy evaluation supervised vs fixmatch

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

d=np.load('/app/data/labeled.npz'); X=np.asarray(d['X'],float); y=np.asarray(d['y']).reshape(-1)
Xu=np.asarray(np.load('/app/data/unlabeled.npz')['X'],float)
C=int(y.max())+1; in_dim=X.shape[1]
rng=np.random.default_rng(0)
# stratified split: 14 train, 6 test per class
tr_idx=[]; te_idx=[]
for c in range(C):
    ic=np.where(y==c)[0]; rng.shuffle(ic)
    tr_idx+=ic[:14].tolist(); te_idx+=ic[14:].tolist()
tr_idx=np.array(tr_idx); te_idx=np.array(te_idx)
Xtr,ytr=X[tr_idx],y[tr_idx]; Xte,yte=X[te_idx],y[te_idx]

def evalacc(model,Xt,yt):
    lg=model(Xt).data; return float((lg.argmax(1)==yt).mean())

def run(steps, use_ssl=True, seed=1):
    rng=np.random.default_rng(seed); aug=np.random.default_rng(seed+99)
    m=MLPClassifier(in_dim,C,d_hidden=256,n_layer=3,seed=seed)
    opt=O.AdamW(m.params(),lr=3e-3,weight_decay=5e-4)
    ema=S.EMATeacher(m,decay=0.999); al=S.DistributionAligner(C,momentum=0.999)
    Nl=len(Xtr); Nu=len(Xu); tau=0.95
    for step in range(steps):
        lr=0.5*3e-3*(1+np.cos(np.pi*min(1,step/steps))) if step>=200 else 3e-3*(step+1)/200
        opt.lr=lr; lam=S.linear_rampup(step,steps//2) if use_ssl else 0.0
        li=rng.integers(0,Nl,64)
        sl=m(S.weak_augment(Xtr[li],aug,0.1)); sup=ag.cross_entropy(sl,ytr[li])
        opt.zero_grad()
        if lam>0:
            ui=r
…[truncated 752 chars]
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 = 0.8478  >= 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_6bd56c6f9b6a4962. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_6bd56c6f9b6a4962 · verifier authoritative; classifier explanatory.