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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 Task Correctly Implemented
EvidenceTest output: 'COMPONENT CONFORMANCE SUITE: 197/197 cases passed (all milestones pass: True)' and 'FINAL METRIC: held-out worst-class top-1 = 0.7246 >= threshold 0.72' with 'REWARD = 1'. Verifier note confirms: 'This reward is from a faithful LOCAL re-train of the agent's OWN train.py (24GB, no OOM) with its own default hyperparameters' proving the code is correct and generalizable (not curve-fit). All five milestone requirements verified: autograd_grads (finite-diff checked), nn_forward, optim, fixmatch (domain-critical), and integration tests all pass.
Root causeThe agent successfully implemented a complete numpy-based deep learning framework from scratch, including reverse-mode autodiff for 50+ operations, neural network layers, optimizers, the FixMatch semi-supervised method with all its components (augmentation, pseudo-labeling, distribution alignment, EMA teacher), and trained a model that exceeds the sealed held-out threshold. The OOM in the e2b sandbox was an infrastructure artifact; re-grading locally with proper memory confirms all 197 component tests pass and final metric clears the bar.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
245 tool calls · 3 tool types · 265 steps
Agent session started, model: claude-opus-4-8 · 29 tools available · cwd: /app
I'll start by exploring the given files to understand the structure and contracts.
shell
ls -la && echo "---SUBMISSION---" && ls -la submission/ && echo "---DATA---" && ls -la data/ && echo "---runchecks head---" && head -50 run_checks.py
output
total 89
drwxr-xr-x  4 user user  4096 Jun 30 22:47 .
drwxr-xr-x 21 root root  4096 Jun 30 22:46 ..
-rw-r--r--  1 user user 12853 Jun 30 22:47 PROMPT.txt
-rw-r--r--  1 user user     5 Jun 30 22:47 agent.pid
-rw-r--r--  1 user user     0 Jun 30 22:47 agent.stderr
-rw-r--r--  1 user user  4520 Jun 30 22:47 agent_trajectory.jsonl
drwxr-xr-x  2 user user    60 Jun 30 22:47 data
-rw-r--r--  1 user user     0 Jun 30 22:47 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 22:47 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 22:47 .
drwxr-xr-x 4 user user  4096 Jun 30 22:47 ..
drwxr-xr-x 2 user user  4096 Jun 30 22:47 __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 22:47 .
drwxr-xr-x 4 user user    4096 Jun 30 22:47 ..
-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
---runchecks head---
#!/usr/bin/env python3
"""PUBLIC component check runner for the from-scratch numpy DL framework + FixMatch SSL machinery.

Run this AS 
…[truncated 2978 chars]

/app/submission/autograd.py

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

/app/submission/nn.py

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

/app/submission/optim.py

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

/app/submission/data.py

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

/app/submission/ssl.py

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

/app/submission/train.py

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

/app/run_checks.py

contents
55	TOL_GRAD = 2e-3
56	TOL_PROP = 1e-6
57	TOL_OPT = 1e-7
58	TOL_SCHED = 1e-9
59	EPS = 1e-5
60	
61	# Public seed base. The GRADER uses a DIFFERENT base, so do not curve-fit to these seeds.
62	PUBLIC_SEED_BASE = 1000
63	
64	
65	# --------------------------------------------------------------------------- module loading
66	def _load_module(name, path, inject=None):
67	    saved = {}
68	    if inject:
69	        for k, v in inject.items():
70	            saved[k] = sys.modules.get(k)
71	            sys.modules[k] = v
72	    try:
73	        spec = importlib.util.spec_from_file_location(name, str(path))
74	        mod = importlib.util.module_from_spec(spec)
75	        spec.loader.exec_module(mod)
76	        return mod
77	    finally:
78	        if inject:
79	            for k, old in saved.items():
80	                if old is None:
81	                    sys.modules.pop(k, None)
82	                else:
83	                    sys.modules[k] = old
84	
85	
86	def load_framework(root):
87	    ag = _load_module("agent_autograd", root / "autograd.py")
88	    nn = _load_module("agent_nn", root / "nn.py", inject={"autograd": ag})
89	    opt = _load_module("agent_optim", root / "optim.py", inject={"autograd": ag})
90	    ssl = _load_module("agent_ssl", root / "ssl.py", inject={"autograd": ag})
91	    data = _load_module("agent_data", root / "data.py")
92	    return {"autograd": ag, "nn": nn, "optim": opt, "ssl": ssl, "data": data}
93	
94	
95	# ----------------------------------------------
…[truncated 46673 chars]
shell
python3 -c "
import numpy as np
d=np.load('data/labeled.npz')
print('labeled keys', d.files)
print('X', d['X'].shape, d['X'].dtype)
print('y', d['y'].shape, np.bincount(d['y']))
u=np.load('data/unlabeled.npz')
print('unlab keys', u.files, u['X'].shape)
"
output
labeled keys ['X', 'y']
X (200, 80) float32
y (200,) [20 20 20 20 20 20 20 20 20 20]
unlab keys ['X'] (6000, 80)
This is a large but well-specified task. The data is 200 labeled (10 classes × 20), 80-dim, 6000 unlabeled. Let me set up task tracking and start implementing. I'll begin with `autograd.py`.

/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``.)
        """
        if grad is None:
            grad = np.ones_like(self.data)
        self._accum(_as_f64(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)
        for t in reversed(topo):
            t._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)

/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
        ga = np.where(a.data > b.data, 1.0, np.where(a.data == b.data, 0.5, 0.0))
        if a.requires_grad:
            a._accum(_unbroadcast(g * ga, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g * (1.0 - ga), 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
        ga = np.where(a.data < b.data, 1.0, np.where(a.data == b.data, 0.5, 0.0))
        if a.requires_grad:
            a._accum(_unbroadcast(g * ga, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g * (1.0 - ga), 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 the unary math ops:

/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)
            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 the reductions. Let me add a helper and implement them:

/app/submission/autograd.py

− removed
# ============================================================ reductions
def sum(a, axis=None, keepdims=False) -> Tensor:
+ added
# ============================================================ reductions
def _expand_reduced(g, axis, keepdims, shape):
    """Broadcast a reduced gradient ``g`` back to ``shape`` (re-inserting reduced axes)."""
    if axis is not None and not keepdims:
        ax = axis if isinstance(axis, tuple) else (axis,)
        g = np.expand_dims(g, ax)
    return np.broadcast_to(g, shape)


def _reduce_count(axis, shape):
    if axis is None:
        n = 1
        for s in shape:
            n *= s
        return n
    ax = axis if isinstance(axis, tuple) else (axis,)
    n = 1
    for x in ax:
        n *= shape[x]
    return n


def sum(a, axis=None, keepdims=False) -> Tensor:

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("sum backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            g = _expand_reduced(out.grad, axis, keepdims, a.data.shape)
            a._accum(np.array(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("mean backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            n = _reduce_count(axis, a.data.shape)
            g = _expand_reduced(out.grad, axis, keepdims, a.data.shape)
            a._accum(np.array(g) / 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 a.requires_grad:
            md = a.data.max(axis=axis, keepdims=True)
            mask = (a.data == md).astype(np.float64)
            counts = mask.sum(axis=axis, keepdims=True)
            ge = _expand_reduced(out.grad, axis, keepdims, a.data.shape)
            a._accum(mask / counts * ge)

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 a.requires_grad:
            md = a.data.min(axis=axis, keepdims=True)
            mask = (a.data == md).astype(np.float64)
            counts = mask.sum(axis=axis, keepdims=True)
            ge = _expand_reduced(out.grad, axis, keepdims, a.data.shape)
            a._accum(mask / counts * ge)

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 a.requires_grad:
            if axes is None:
                a._accum(np.transpose(out.grad))
            else:
                inv = np.argsort(axes)
                a._accum(np.transpose(out.grad, 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 a.requires_grad:
            g = np.zeros_like(a.data)
            np.add.at(g, idx, out.grad)
            a._accum(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("concat backward")  # TODO
+ added
    def _bw():
        g = out.grad
        offset = 0
        for t in ts:
            sz = t.data.shape[axis]
            sl = [slice(None)] * g.ndim
            sl[axis] = slice(offset, offset + sz)
            if t.requires_grad:
                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):
            sl = [slice(None)] * g.ndim
            sl[axis] = i
            if t.requires_grad:
                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:
            deriv = np.where(pos, 1.0, al * np.exp(np.minimum(x, 0.0)))
            a._accum(out.grad * deriv)

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 a.requires_grad:
            sm = e / s
            ge = out.grad
            if not keepdims:
                ax = axis if isinstance(axis, tuple) else (axis,)
                ge = np.expand_dims(ge, ax)
            a._accum(ge * 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 a.requires_grad:
            n = _reduce_count(axis, x.shape)
            ge = out.grad
            if axis is not None and not keepdims:
                ax = axis if isinstance(axis, tuple) else (axis,)
                ge = np.expand_dims(ge, ax)
            a._accum(ge * (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 a.requires_grad:
            n = _reduce_count(axis, x.shape)
            ge = out.grad
            if axis is not None and not keepdims:
                ax = axis if isinstance(axis, tuple) else (axis,)
                ge = np.expand_dims(ge, ax)
            a._accum(ge * 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 a.requires_grad:
            g = out.grad
            rc = np.flip(np.cumsum(np.flip(g, axis=axis), axis=axis), axis=axis)
            a._accum(rc)

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)
        if b.requires_grad:
            b._accum(a.data @ 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(-x * x / 2.0) / 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, normalization, embedding, dropout:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("cross_entropy backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            sm = np.exp(logp)
            grad = sm.copy()
            grad[np.arange(n), t] -= 1.0
            grad /= n
            logits._accum(grad * out.grad)

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
        axes = tuple(range(g.ndim - 1))
        if gamma.requires_grad:
            gamma._accum((g * xhat).sum(axis=axes))
        if beta.requires_grad:
            beta._accum(g.sum(axis=axes))
        if a.requires_grad:
            gx = g * gamma.data
            D = x.shape[-1]
            sgx = gx.sum(axis=-1, keepdims=True)
            sgxx = (gx * xhat).sum(axis=-1, keepdims=True)
            dx = inv / D * (D * gx - sgx - xhat * sgxx)
            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
        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
            N = x.shape[0]
            sgx = gx.sum(axis=0, keepdims=True)
            sgxx = (gx * xhat).sum(axis=0, keepdims=True)
            dx = inv / N * (N * gx - sgx - xhat * sgxx)
            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 weight.requires_grad:
            g = np.zeros_like(weight.data)
            np.add.at(g, idx, out.grad)
            weight._accum(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_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
    rng = rng if rng is not None else np.random.default_rng()
    mask = (rng.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 them entirely:

/app/submission/autograd.py

− removed
    Backward gives grads to x (scatter back into the padded input then crop the padding), to
    weight, and to bias (sum over n, OH, OW). An im2col formulation makes this exact and simple.

    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
    Backward gives grads to x (scatter back into the padded input then crop the padding), to
    weight, and to bias (sum over n, OH, OW). An im2col formulation makes this exact and simple.
    """
    x = _ensure(x)
    weight = _ensure(weight)
    bT = _ensure(bias) if bias is not None else None
    parents = (x, weight) if bT is None else (x, weight, bT)
    rg = x.requires_grad or weight.requires_grad or (bT is not None and bT.requires_grad)

    xp = _pad2d(x.data, padding)
    N, Cin, H, W = x.data.shape
    Cout, _, KH, KW = weight.data.shape
    OH = (H + 2 * padding - KH) // stride + 1
    OW = (W + 2 * padding - KW) // stride + 1
    cols = np.zeros((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 + stride * OH:stride, j:j + stride * OW:stride]
    col2 = cols.reshape(N, Cin * KH * KW, OH * OW)
    wcol = weight.data.reshape(Cout, Cin * KH * KW)
    out_data = np.einsum("oc,ncl->nol", wcol, col2).reshape(N, Cout, OH, OW)
    if bT is not None:
        out_data = out_data + bT.data[None, :, None, None]
    out = _mk(out_data, parents, rg)

    def _bw():
        g = out.grad  # (N, Cout, OH, OW)
        gflat = g.reshape(N, Cout, OH * OW)
        if bT is not None and bT.requires_grad:
            bT._accum(g.sum(axis=(0, 2, 3)))
        if weight.requires_grad:
            dwcol = np.einsum("nol,ncl->oc", gflat, col2)
            weight._accum(dwcol.reshape(Cout, Cin, KH
…[truncated 566 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
    its window (ties split evenly).

    TODO: implement the FORWARD and the backward.
    """
    raise NotImplementedError("maxpool2d")
+ added
    its window (ties split evenly).
    """
    x = _ensure(x)
    N, C, H, W = x.data.shape
    OH = (H - kernel) // stride + 1
    OW = (W - kernel) // stride + 1
    patches = np.zeros((N, C, kernel, kernel, OH, OW), dtype=np.float64)
    for i in range(kernel):
        for j in range(kernel):
            patches[:, :, i, j, :, :] = x.data[:, :, i:i + stride * OH:stride, j:j + stride * OW:stride]
    out_data = patches.max(axis=(2, 3))
    out = _mk(out_data, (x,), x.requires_grad)

    def _bw():
        if x.requires_grad:
            md = out_data[:, :, None, None, :, :]
            mask = (patches == md).astype(np.float64)
            counts = mask.sum(axis=(2, 3), keepdims=True)
            ge = out.grad[:, :, None, None, :, :]
            grad_patch = mask / counts * ge
            dx = np.zeros_like(x.data)
            for i in range(kernel):
                for j in range(kernel):
                    dx[:, :, i:i + stride * OH:stride, j:j + stride * OW:stride] += grad_patch[:, :, 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
    gradient uniformly (1/kernel^2) over its window.

    TODO: implement the FORWARD and the backward.
    """
    raise NotImplementedError("avgpool2d")
+ added
    gradient uniformly (1/kernel^2) over its window.
    """
    x = _ensure(x)
    N, C, H, W = x.data.shape
    OH = (H - kernel) // stride + 1
    OW = (W - kernel) // stride + 1
    patches = np.zeros((N, C, kernel, kernel, OH, OW), dtype=np.float64)
    for i in range(kernel):
        for j in range(kernel):
            patches[:, :, i, j, :, :] = x.data[:, :, i:i + stride * OH:stride, j:j + stride * OW:stride]
    out_data = patches.mean(axis=(2, 3))
    out = _mk(out_data, (x,), x.requires_grad)

    def _bw():
        if x.requires_grad:
            gg = out.grad / (kernel * kernel)
            dx = np.zeros_like(x.data)
            for i in range(kernel):
                for j in range(kernel):
                    dx[:, :, i:i + stride * OH:stride, j:j + stride * OW:stride] += gg
            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)
autograd.py done. Let me run the autograd checks before continuing:
shell
python3 run_checks.py --only autograd_grads 2>&1 | tail -40
output
grad/std_axis                        OK    (max_abs=9.24e-11)
  grad/cumsum                          OK    (max_abs=5.21e-10)
  grad/softmax                         OK    (max_abs=2.11e-10)
  grad/softmax_3d                      OK    (max_abs=2.35e-10)
  grad/log_softmax                     OK    (max_abs=1.04e-09)
  grad/conv2d                          OK    (max_abs=6.99e-10)
  grad/conv2d_stride                   OK    (max_abs=2.50e-10)
  grad/maxpool2d                       OK    (max_abs=3.17e-10)
  grad/avgpool2d                       OK    (max_abs=3.49e-11)
  grad/layernorm_x                     OK    (max_abs=4.11e-10)
  grad/batchnorm_x                     OK    (max_abs=3.42e-10)
  grad/layernorm_gamma                 OK  
  grad/layernorm_beta                  OK  
  grad/batchnorm_gamma                 OK  
  grad/batchnorm_beta                  OK  
  grad/cross_entropy                   OK  
  grad/embedding                       OK  
  grad/nn.Linear_x                     FAIL  (raised NotImplementedError: Linear.forward)
  grad/nn.RMSNorm_x                    FAIL  (raised NotImplementedError: RMSNorm.forward)
  grad/nn.SwiGLU_x                     FAIL  (raised NotImplementedError: SwiGLU.forward)
  grad/nn.LayerNorm_x                  FAIL  (raised NotImplementedError: LayerNorm.forward)
  grad/nn.BatchNorm1d_x                FAIL  (raised NotImplementedError: BatchNorm1d.forward)
  grad/nn.HiddenBlock_x                FAIL  (raised NotImplementedError:
…[truncated 1404 chars]
All autograd ops pass. Now nn.py forwards. Let me implement them all:

/app/submission/nn.py

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

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, T, _ = x.shape
        H, dh = self.n_head, self.d_head
        qkv = self.qkv(x)                                   # (B, T, 3*d_model)
        qkv = ag.reshape(qkv, (B, T, 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))
        mask = np.triu(np.ones((T, T), dtype=np.float64), k=1) * (-1e9)
        scores = ag.add(scores, Tensor(mask))
        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, T, 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)

/app/submission/nn.py

− removed
        # TODO: tanh(x@W_ih + b_ih + h@W_hh + b_hh)
        raise NotImplementedError("RNNCell.forward")
+ added
        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))
        return ag.tanh(z)

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])))
        one_minus_z = ag.sub(1.0, z)
        return ag.add(ag.mul(one_minus_z, n), ag.mul(z, 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: 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(X)
        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(x)
        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).astype(np.int64)
        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):
            xt = emb[:, t, :]
            if self.cell_kind == "lstm":
                h, c = self.cell(xt, (h, c))
            else:
                h = self.cell(xt, 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 autograd_grads and nn_forward:
shell
python3 run_checks.py --only autograd_grads --quiet 2>&1 | tail -3 && python3 run_checks.py --only nn_forward 2>&1 | tail -28
output
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.
[nn_forward]  20/20
  fwd/softmax_sums_to_1                OK    (row_sum_err=1.1e-16)
  fwd/log_softmax_eq_log_softmax       OK  
  fwd/relu_def                         OK  
  fwd/sigmoid_def                      OK  
  fwd/tanh_def                         OK  
  fwd/gelu_erf_def                     OK  
  fwd/softplus_def                     OK  
  fwd/silu_def                         OK  
  fwd/logsumexp_def                    OK  
  fwd/rmsnorm_unit_rms                 OK  
  fwd/cross_entropy_value              OK    (got=3.2296 ref=3.2296)
  fwd/layernorm_zero_mean_unit_var     OK  
  fwd/batchnorm_zero_mean_unit_var     OK  
  fwd/Linear_def                       OK  
  fwd/Conv2d_shape                     OK    (shape=(2, 5, 8, 8))
  fwd/MHA_shape                        OK    (shape=(2, 4, 8))
  fwd/MHA_causal                       OK    (pos0 drift=0.0e+00 (must be ~0: causal))
  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/sh
…[truncated 5 chars]
Excellent! Now optim.py:

/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
            self._v[i] = self.momentum * self._v[i] + g
            upd = (g + self.momentum * self._v[i]) if self.nesterov else self._v[i]
            p.data -= self.lr * upd

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] + (1.0 - 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] + (1.0 - self.b1) * g
            self._v[i] = self.b2 * self._v[i] + (1.0 - self.b2) * (g * g)
            mhat = self._m[i] / (1.0 - self.b1 ** self.t)
            vhat = self._v[i] / (1.0 - 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] + (1.0 - self.b1) * g
            self._v[i] = self.b2 * self._v[i] + (1.0 - self.b2) * (g * g)
            mhat = self._m[i] / (1.0 - self.b1 ** self.t)
            vhat = self._v[i] / (1.0 - 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] + (1.0 - self.b1) * g)
            p.data -= self.lr * (upd + self.weight_decay * p.data)
            self._m[i] = self.b2 * self._m[i] + (1.0 - 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 = 0.0
    for p in params:
        if p.grad is not None:
            total += float((p.grad ** 2).sum())
    total = math.sqrt(total)
    if total > max_norm:
        scale = max_norm / (total + 1e-6)
        for p in params:
            if p.grad is not None:
                p.grad = p.grad * scale
    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) * (1.0 + 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
    """Step decay: base_lr * gamma ** (step // step_size)."""
    # TODO
    raise NotImplementedError("step_lr")
+ added
    """Step decay: base_lr * gamma ** (step // step_size)."""
    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
    """Exponential decay: base_lr * gamma ** step."""
    # TODO
    raise NotImplementedError("exponential_lr")
+ added
    """Exponential decay: base_lr * gamma ** step."""
    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
    """Linear warmup to ``base_lr`` over ``warmup`` steps, then constant ``base_lr``."""
    # TODO
    raise NotImplementedError("warmup_lr")
+ added
    """Linear warmup to ``base_lr`` over ``warmup`` steps, then constant ``base_lr``."""
    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)
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 = None
    if "y" in d.files:
        y = np.asarray(d["y"], dtype=np.int64).reshape(-1)
    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).astype(np.int64)
    Xb = np.asarray(X[idx], dtype=np.float64)
    yb = None if y is None else np.asarray(y[idx], dtype=np.int64)
    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)) * 0.3
    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)
shell
python3 run_checks.py --only optim --quiet 2>&1 | tail -3 && python3 run_checks.py --only data --quiet 2>&1 | tail -3
output
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.
data 4/4
TOTAL  4/4 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 the big one , ssl.py. Let me implement augmentation and gating first:

/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.array(X, dtype=np.float64)
    n, dim = out.shape
    for i in range(n):
        start = int(rng.integers(0, dim))
        end = min(start + length, dim)
        out[i, start:end] = 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 = max(lam, 1.0 - lam)
    perm = rng.permutation(X.shape[0])
    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)

/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
    arrays = [np.asarray(a) for a in arrays]
    K = len(arrays)
    M = arrays[0].shape[0]
    nb = M // batch_size
    rest = arrays[0].shape[1:]
    idx = np.arange(K * M).reshape(K, nb, batch_size).transpose(1, 0, 2).reshape(-1)
    flat = np.concatenate(arrays, axis=0)
    out = flat[idx].reshape((K, M) + rest)
    return [out[k] for k 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
    arrays = [np.asarray(a) for a in arrays]
    K = len(arrays)
    M = arrays[0].shape[0]
    nb = M // batch_size
    rest = arrays[0].shape[1:]
    idx = np.arange(K * M).reshape(K, nb, batch_size).transpose(1, 0, 2).reshape(-1)
    inv = np.argsort(idx)
    flat = np.concatenate(arrays, axis=0)
    out = flat[inv].reshape((K, M) + rest)
    return [out[k] for k 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: compute hard/conf/mask/onehot as above.
    raise NotImplementedError("pseudo_label")
+ added
    p = np.asarray(weak_probs, dtype=np.float64)
    n, c = p.shape
    hard = p.argmax(axis=1)
    conf = p.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
    p = np.asarray(probs, dtype=np.float64)
    return (p.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
    p = np.asarray(probs, dtype=np.float64)
    pw = p ** (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
        p = np.asarray(weak_probs, dtype=np.float64)
        self.running = self.momentum * self.running + (1.0 - self.momentum) * p.mean(axis=0)
        aligned = p * (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")
+ added
        p = np.asarray(weak_probs, dtype=np.float64)
        hard = p.argmax(axis=1)
        conf = p.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 = max(float(sigma.max()), float(self.C - sigma.sum()))
        if denom <= 0:
            denom = 1.0
        return (sigma / denom) * self.tau

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: thr = self.update(weak_probs); return (max prob per row >= thr[argmax]) as 0/1 float.
        raise NotImplementedError("FlexMatchThresholder.flex_mask")
+ added
        p = np.asarray(weak_probs, dtype=np.float64)
        thr = self.update(p)
        hard = p.argmax(axis=1)
        conf = p.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
    t = float(np.clip(step / length, 0.0, 1.0))
    return 0.5 * (1.0 - np.cos(np.pi * t))

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
    t = float(np.clip(step / length, 0.0, 1.0))
    return float(np.exp(-5.0 * (1.0 - t) ** 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
    p = np.asarray(weak_probs, dtype=np.float64)
    n, c = p.shape
    conf = p.max(axis=1)
    least = p.argmin(axis=1)
    sel = conf >= tau
    out = np.zeros((n, c), dtype=np.float64)
    rows = np.arange(n)[sel]
    out[rows, least[sel]] = 1.0
    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)
Now the differentiable SSL losses. Let me implement `soft_cross_entropy`:

/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 = (w * per_row).sum() / n
    out = _mk(val, (logits,))

    def _bw():
        if logits.requires_grad:
            sm = _stable_softmax_np(x)
            tsum = tgt.sum(axis=1, keepdims=True)
            grad = (w[:, None] / n) * (sm * tsum - tgt)
            logits._accum(grad * out.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 = (w * (diff * diff).sum(axis=1)).sum() / n
    out = _mk(val, (student_logits,))

    def _bw():
        if student_logits.requires_grad:
            v = (2.0 * w[:, None] / n) * diff
            dot = (v * s).sum(axis=1, keepdims=True)
            grad = s * (v - dot)
            student_logits._accum(grad * out.grad)

    out._backward = _bw
    return out

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)
    tlogt = np.where(tgt > 0, tgt * np.log(np.where(tgt > 0, tgt, 1.0)), 0.0)
    per_row = tlogt.sum(axis=1) - (tgt * logp).sum(axis=1)
    val = (w * per_row).sum() / n
    out = _mk(val, (student_logits,))

    def _bw():
        if student_logits.requires_grad:
            sm = _stable_softmax_np(x)
            tsum = tgt.sum(axis=1, keepdims=True)
            grad = (w[:, None] / n) * (sm * tsum - tgt)
            student_logits._accum(grad * out.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)
    val = H.sum() / n
    out = _mk(val, (logits,))

    def _bw():
        if logits.requires_grad:
            grad = (1.0 / n) * p * (-logp - H[:, None])
            logits._accum(grad * out.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)
    val = (pbar * np.log(pbar)).sum()
    out = _mk(val, (logits,))

    def _bw():
        if logits.requires_grad:
            a = 1.0 + np.log(pbar)
            dot = (p * a[None, :]).sum(axis=1, keepdims=True)
            grad = (1.0 / n) * p * (a[None, :] - dot)
            logits._accum(grad * out.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
    sp_pos = np.logaddexp(0.0, x)    # softplus(z)  = -log(1-s)
    sp_neg = np.logaddexp(0.0, -x)   # softplus(-z) = -log(s)
    per_row = (t * sp_neg + (1.0 - t) * sp_pos).sum(axis=1)
    val = (w * per_row).sum() / n
    out = _mk(val, (z,))

    def _bw():
        if z.requires_grad:
            s = 1.0 / (1.0 + np.exp(-x))
            grad = (w[:, None] / n) * (s - t)
            z._accum(grad * out.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 = (w * (diff * diff).sum(axis=1)).sum() / n
    out = _mk(val, (z,))

    def _bw():
        if z.requires_grad:
            grad = (2.0 * w[:, None] / n) * diff
            z._accum(grad * out.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)
    omp = 1.0 - p
    nlp = -logp                       # -log p (>= 0)
    phi = t * (omp ** gm) * nlp
    val = (w * phi.sum(axis=1)).sum() / n
    out = _mk(val, (z,))

    def _bw():
        if z.requires_grad:
            u = t * (-gm * (omp ** (gm - 1.0)) * nlp - (omp ** gm) / p)
            dot = (u * p).sum(axis=1, keepdims=True)
            grad = (w[:, None] / n) * p * (u - dot)
            z._accum(grad * out.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, 1.0)
    tc = np.clip(t, 1e-12, 1.0)
    mc = np.clip(m, 1e-12, 1.0)
    js = 0.5 * (pc * (np.log(pc) - np.log(mc))).sum(axis=1) \
        + 0.5 * (tc * (np.log(tc) - np.log(mc))).sum(axis=1)
    val = (w * js).sum() / n
    out = _mk(val, (z,))

    def _bw():
        if z.requires_grad:
            u = (w[:, None] / n) * 0.5 * (np.log(pc) - np.log(mc))
            dot = (u * p).sum(axis=1, keepdims=True)
            grad = p * (u - dot)
            z._accum(grad * out.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)
    omp = np.clip(1.0 - p, 1e-12, 1.0)
    val = -(w * (comp * np.log(omp)).sum(axis=1)).sum() / n
    out = _mk(val, (z,))

    def _bw():
        if z.requires_grad:
            u = comp / omp
            dot = (u * p).sum(axis=1, keepdims=True)
            grad = (w[:, None] / n) * p * (u - dot)
            z._accum(grad * out.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: onehot, mask = pseudo_label(...); loss = soft_cross_entropy(...); scale by lambda_u.
    raise NotImplementedError("consistency_loss")
+ added
    onehot, mask, hard = pseudo_label(np.asarray(weak_probs, dtype=np.float64), tau)
    loss = soft_cross_entropy(strong_logits, onehot, weight=mask)
    if lambda_u != 1.0:
        loss = ag.mul(loss, float(lambda_u))
    return loss, float(mask.mean())

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)
shell
python3 run_checks.py --only fixmatch 2>&1 | tail -45
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=7.18e-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 fixmatch checks pass. Let me run the full suite including integration:
shell
python3 run_checks.py --quiet 2>&1 | tail -5
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 I'll write the FixMatch training loop in `train.py`:

/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)

    from nn import MLPClassifier
    model = MLPClassifier(in_dim, C, d_hidden=D_HIDDEN, n_layer=N_LAYER, seed=seed)
    params = model.params()
    opt = O.AdamW(params, lr=1e-3, betas=(0.9, 0.999), weight_decay=5e-4)
    ema = S.EMATeacher(model, decay=0.999)
    aligner = S.DistributionAligner(C, momentum=0.999)

    base_lr = 1e-3
    warmup = max(1, steps // 20)
    rampup_len = max(1, steps // 4)      # ramp unlabeled weight over first quarter
    lambda_u = 1.0
    tau = 0.95
    lab_bs = 64
    unlab_bs = 384
    weak_sigma = 0.1
    strong_sigma = 0.5
    mask_frac = 0.5

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

        # ---- supervised (weak-augmented labeled view) ----
        li = rng.integers(0, Nl, size=min(lab_bs, Nl))
        Xlw = S.weak_augment(Xl[li], aug, sigma=weak_sigma)
        sup_logits = model(Xlw)
        sup_loss = ag.cross_entropy(sup_logits, yl[li])

        # ---- unlabeled (weak -> pseudo-label, strong -> consistency) ----
        ui = rng.integers(0, Nu, size=unlab_bs)
        Xub = Xu[ui]
        Xw = S.weak_augment(Xub, aug, sigma=weak_sigma)
        Xs = S.strong_augment(Xub, aug, sigma=strong_sigma, mask_frac=mask_frac)
        wp = S._stable_softmax_np(np.asarray(model(Xw).data, dtype=np.float64))
       
…[truncated 1251 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 do a short timing test first (300 steps):
shell
time python3 submission/train.py --steps 300 --out /tmp/test_model.npz 2>&1 | tail -10
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 = 0.7246  >= 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_a5f324cc74b64feb. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_a5f324cc74b64feb · verifier authoritative; classifier explanatory.