SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

worst-group-spurious-dfr

claude-code claude-opus-4-8 ✗ failed GOOD_FAILURE ↑ View task
Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.
Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.
Classification , post-hoc; cannot change the reward
GOOD_FAILUREHonest miss, the agent ran correctly but couldn't solve it. Expected for a hard task; the task is sound.
SubtypeInsufficient Exploration / Tuning
EvidenceTest output: 'COMPONENT CONFORMANCE SUITE: 194/194 cases passed (all milestones pass: True)' + 'FINAL METRIC: worst-group accuracy = 0.75 < threshold 0.86'. The verifier note confirms: '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' , the framework implementation is 100% correct, but training failed to reach the sealed threshold.
Root causeThe agent correctly implemented the complete numpy-only deep-learning framework with all ~60 autograd ops, conv2d/pool/batchnorm backprop, and robustness losses , all 194 component tests passed. However, the agent's training recipe and hyperparameters were insufficient to push worst-group accuracy from 0.75 to the sealed threshold of 0.86, which is calibrated to sit just under a strong fully-tuned DFR oracle.
RecommendationN/A - task is fine. This is a hard task by design. The agent succeeded at the implementation challenge (demonstrable via 194/194 passing conformance tests) but fell short on the training tuning challenge. A developer with more iteration time could experiment with: better group-balanced data scheduling, different optimizer choices (e.g., group-DRO vs DFR ensemble), more careful learning rate / warmup tuning, or using the reweight.npz dataset more effectively for head-fitting.
Trajectory
Tool-by-tool agent trajectory
230 tool calls · 3 tool types · 255 steps
Agent session started, model: claude-opus-4-8 · 29 tools available · cwd: /app
I'll start by exploring the task structure to understand what I'm working with.

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 22:48 .
drwxr-xr-x 21 root root  4096 Jun 30 22:47 ..
-rw-r--r--  1 user user 14914 Jun 30 22:48 PROMPT.txt
-rw-r--r--  1 user user     5 Jun 30 22:48 agent.pid
-rw-r--r--  1 user user     0 Jun 30 22:48 agent.stderr
-rw-r--r--  1 user user  4511 Jun 30 22:48 agent_trajectory.jsonl
drwxr-xr-x  2 user user    60 Jun 30 22:48 data
-rw-r--r--  1 user user     0 Jun 30 22:48 run.log
-rwxr-xr-x  1 user user 45855 Jun 30 11:01 run_checks.py
drwxr-xr-x  3 user user   128 Jun 30 22:48 submission
-rwxr-xr-x  1 user user  1318 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 22:48 .
drwxr-xr-x 4 user user  4096 Jun 30 22:48 ..
drwxr-xr-x 2 user user  4096 Jun 30 22:48 __pycache__
-rw-r--r-- 1 user user 48121 Jun 30 11:01 autograd.py
-rw-r--r-- 1 user user  1692 Jun 30 11:01 data.py
-rw-r--r-- 1 user user 23705 Jun 30 11:01 nn.py
-rw-r--r-- 1 user user 12275 Jun 30 11:01 optim.py
-rw-r--r-- 1 user user  2900 Jun 30 11:01 train.py
---DATA---
total 11108
drwxr-xr-x 2 user user      60 Jun 30 22:48 .
drwxr-xr-x 4 user user    4096 Jun 30 22:48 ..
-rw-r--r-- 1 user user 3953364 Jun 30 11:01 reweight.npz
-rw-r--r-- 1 user user 7411924 Jun 30 11:01 train.npz
Let me read all the stub files to understand the structure.

/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 / group-weighting fails the 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	* 
…[truncated 52049 chars]
Now let me read the remaining files.

/app/submission/nn.py

contents
1	"""Neural-network layers + models + the robustness machinery, built on YOUR autograd engine.
2	
3	Implement every ``# TODO`` forward (and the robustness-helper bodies). The parameters +
4	``named_params`` naming + the checkpoint round-trip are already wired; you compose the autograd
5	ops. The grader checks each layer's forward against its OWN reference AND finite-difference-checks
6	the gradients that flow through your autograd, so the composition must be exactly right.
7	
8	THE FINAL-METRIC MODEL is the pinned ``SmallCNN`` (a conv FEATURE EXTRACTOR + a single linear
9	CLASSIFIER). The split is what makes last-layer retraining (DFR) on a group-balanced set
10	expressible against the pinned graph: freeze the extractor and re-fit ONLY ``classifier``.
11	``featurize(X, training)`` returns the post-ReLU embedding so you can freeze the extractor.
12	
13	The other layers/models (Linear / Conv2d / BatchNorm2d / BatchNorm1d / LayerNorm / Dropout /
14	AvgPool2d / MLP / ResidualMLP / a TinyConvNet) are exercised by the conformance suite across a
15	WIDE surface -- each is an independent potential bug. The robustness machinery (``GroupDROState``
16	exponentiated-gradient adversary-weight update, ``balanced_group_weights``,
17	``class_balanced_weights``, ``log_class_prior``) is the domain-specific heart this task adds; the
18	``robust`` milestone checks them.
19	
20	SmallCNN naming contract (do not change -- the verifier indexes by these exact keys):
21	  conv1.weight (Wd,3,3,3) | con
…[truncated 24273 chars]

/app/submission/optim.py

contents
1	"""Optimizers + LR schedulers + grad clipping over a flat list of autograd ``Tensor`` parameters.
2	
3	Implement the ``# TODO`` update math. All optimizers operate IN PLACE on ``param.data`` using
4	``param.grad``. ``zero_grad()`` resets every grad to None. ``t`` is the 1-based step count. The
5	grader runs one (and several) steps of each and compares your updated params against its
6	reference within a tight tolerance, so the math must be EXACTLY right -- every optimizer /
7	scheduler / clipper is an independent potential bug.
8	
9	The training recipe uses AdamW (decoupled weight decay) + ``clip_grad_norm`` for the ERM
10	extractor and the last-layer (DFR) retrain; the rest of the zoo is graded for parity.
11	
12	  SGD     : g = grad + wd*p; v = mu*v + g; upd = (g + mu*v) if nesterov else v; p -= lr*upd
13	  Adagrad : g = grad + wd*p; s += g^2; p -= lr*g/(sqrt(s)+eps)
14	  RMSprop : g = grad + wd*p; s = alpha*s + (1-alpha)*g^2; p -= lr*g/(sqrt(s)+eps)
15	  Adam    : g = grad + wd*p (COUPLED L2); m,v EMA; mhat=m/(1-b1^t); vhat=v/(1-b2^t);
16	            p -= lr*mhat/(sqrt(vhat)+eps)
17	  AdamW   : DECOUPLED wd; m,v EMA; p -= lr*( mhat/(sqrt(vhat)+eps) + wd*p )
18	  Adamax  : m=b1*m+(1-b1)*g; u=max(b2*u, |g|); p -= (lr/(1-b1^t))*m/(u+eps)   (infinity-norm)
19	  NAdam   : m,v EMA; mhat=m/(1-b1^t); vhat=v/(1-b2^t);
20	            mnes = b1*mhat + (1-b1)*g/(1-b1^t);  p -= lr*mnes/(sqrt(vhat)+eps)
21	  Lion    : upd = sign(b1*m + (1-b1)*g); p -= lr*(upd + wd*p); m = b2*m + (1-b2
…[truncated 11759 chars]

/app/submission/data.py

contents
1	"""Data loading + group helpers for the worst-group / spurious-correlation task.
2	
3	Implement the ``# TODO`` bodies (numpy only). The splits ship as ``.npz`` files with arrays
4	``X`` (N,3,S,S) float, ``y`` (the SHAPE class to predict) and ``g`` (the spurious background-color
5	id). A "group" is the pair ``(y, g)``; ``group_ids(y, g, n_classes) = y*n_classes + g`` flattens it
6	to a single id in ``[0, n_classes**2)``.
7	"""
8	from __future__ import annotations
9	
10	from typing import Dict, Tuple
11	
12	import numpy as np
13	
14	
15	def load_npz(path: str) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
16	    """Load (X, y, g) from a .npz; return float64 X, int64 y, int64 g. (Provided.)"""
17	    d = np.load(path)
18	    return (np.asarray(d["X"], dtype=np.float64),
19	            np.asarray(d["y"], dtype=np.int64),
20	            np.asarray(d["g"], dtype=np.int64))
21	
22	
23	def group_ids(y: np.ndarray, g: np.ndarray, n_classes: int) -> np.ndarray:
24	    """Flatten (y, g) to a single group id y*n_classes + g (int64)."""
25	    # TODO
26	    raise NotImplementedError("group_ids")
27	
28	
29	def iterate(X, y, g, batch_size, rng):
30	    """Yield (Xb, yb, gb) minibatches over a random permutation of the dataset."""
31	    # TODO
32	    raise NotImplementedError("iterate")
33	
34	
35	def worst_group_acc(preds, y, g, n_classes) -> Tuple[float, float, Dict[int, float]]:
36	    """Return (min over (y,g) groups of within-group accuracy, average accuracy, per-group dict)."""
37	
…[truncated 318 chars]

/app/submission/train.py

contents
1	"""Training entry point. Implement your worst-group-robust recipe, train the pinned SmallCNN,
2	and save the checkpoint the grader will load.
3	
4	Run it however you like (e.g. ``python3 /app/submission/train.py``). It MUST end by writing
5	``/app/submission/model.npz`` via ``save_checkpoint`` below. The grader loads that file into its
6	OWN reference SmallCNN (architecture pinned to WIDTH/EMBED_DIM below -- keep these) and evaluates
7	WORST-GROUP accuracy on a SEALED, group-balanced test set; you pass the metric part iff
8	worst-group accuracy >= the frozen threshold. (You ALSO must pass the component conformance suite
9	over autograd.py / nn.py / optim.py.)
10	
11	A naive cross-entropy ("ERM") run on the correlated train split will reach high AVERAGE accuracy
12	but ~0 worst-group accuracy -- it keys on the spurious background color. Removing that reliance is
13	the task. One well-known cheap recipe: train the feature extractor on the correlated data, then
14	RE-FIT ONLY the final ``classifier`` on the GROUP-BALANCED reweight split with a group-balanced
15	(group-weighted) loss so the head stops keying off color. You are free to use any method, as long
16	as you submit a state_dict for the pinned architecture.
17	"""
18	from __future__ import annotations
19	
20	import argparse
21	import json
22	import os
23	import sys
24	
25	import numpy as np
26	
27	sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
28	sys.path.insert(0, "/app")
29	sys.path.insert(0, "/app/su
…[truncated 1589 chars]
Now let me look at the run_checks.py to understand exact expectations.

/app/run_checks.py

contents
1	#!/usr/bin/env python3
2	"""PUBLIC component check runner for the from-scratch numpy framework (worst-group / spurious-
3	correlation task).
4	
5	Run this AS OFTEN AS YOU LIKE while you implement to get a per-check progress signal:
6	
7	    python3 /app/run_checks.py                      # check the framework in /app/submission
8	    python3 /app/run_checks.py --submission /dir
9	    python3 /app/run_checks.py --only robust        # focus a single milestone
10	
11	It imports YOUR modules from /app/submission (autograd.py / nn.py / optim.py / data.py), exactly
12	as the grader does, and runs a PUBLIC portion of the component conformance suite, printing a clear
13	per-check report. Each FAIL line names the exact op / layer / optimizer / robustness-loss that is
14	wrong.
15	
16	HOW THIS RELATES TO YOUR GRADE
17	------------------------------
18	This runner is a DEBUGGING AID, not the grader. It checks your framework against self-consistent
19	references it computes on its own:
20	  * autograd_grads : central FINITE-DIFFERENCE of YOUR forward vs YOUR analytic backward.
21	  * nn_forward     : mathematical PROPERTIES your forward must satisfy.
22	  * optim          : YOUR optimizer step vs the closed-form update re-derived here in numpy, for
23	                     every optimizer + the LR schedulers + both grad clippers.
24	  * robust         : finite-diff of YOUR robustness-loss backward + the per-group-normalization /
25	                     Group-DRO / weight-helper PROPERTI
…[truncated 47999 chars]
This is a large but well-specified task. Let me set up tasks and start implementing. First, let me add helper functions and the backward orchestration to autograd.py.

/app/submission/autograd.py

− removed
    while grad.ndim > len(shape):
        grad = grad.sum(axis=0)
    for ax, sz in enumerate(shape):
        if sz == 1 and grad.shape[ax] != 1:
            grad = grad.sum(axis=ax, keepdims=True)
    return grad.reshape(shape)
+ added
    while grad.ndim > len(shape):
        grad = grad.sum(axis=0)
    for ax, sz in enumerate(shape):
        if sz == 1 and grad.shape[ax] != 1:
            grad = grad.sum(axis=ax, keepdims=True)
    return grad.reshape(shape)


def _expand(g, shape, axis, keepdims):
    """Expand an upstream (reduced) gradient ``g`` back to ``shape`` by un-reducing ``axis``."""
    g = np.asarray(g, dtype=np.float64)
    if axis is None:
        return np.broadcast_to(g, shape)
    axes = (axis,) if isinstance(axis, int) else tuple(axis)
    axes = tuple(ax % len(shape) for ax in axes)
    if not keepdims:
        for ax in sorted(axes):
            g = np.expand_dims(g, ax)
    return np.broadcast_to(g, shape)


def _col2im(cols, x_shape, kh, kw, pad, stride, OH, OW):
    """Inverse of ``_im2col``: scatter-add column gradients back to the (strided) input."""
    N, C, H, W = x_shape
    Hp, Wp = H + 2 * pad, W + 2 * pad
    xp = np.zeros((N, C, Hp, Wp), dtype=np.float64)
    c = cols.reshape(N, C, kh, kw, OH, OW)
    st = stride
    for i in range(kh):
        for j in range(kw):
            xp[:, :, i:i + st * OH:st, j:j + st * OW:st] += c[:, :, i, j]
    if pad:
        return xp[:, :, pad:pad + H, pad:pad + W]
    return xp

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 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(v):
            if id(v) in visited:
                return
            visited.add(id(v))
            for p in v._parents:
                build(p)
            topo.append(v)

        build(self)
        if grad is None:
            grad = np.ones_like(self.data)
        self._accum(_as_f64(grad))
        for v in reversed(topo):
            v._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():
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(out.grad, 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():
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(-out.grad, 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():
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad * b.data, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(out.grad * 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():
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad / b.data, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(-out.grad * a.data / (b.data * b.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("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():
        ad, bd = a.data, b.data
        ga = np.where(ad > bd, 1.0, np.where(ad < bd, 0.0, 0.5))
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad * ga, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(out.grad * (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():
        ad, bd = a.data, b.data
        ga = np.where(ad < bd, 1.0, np.where(ad > bd, 0.0, 0.5))
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad * ga, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(out.grad * (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():
        if a.requires_grad:
            a._accum(_unbroadcast(out.grad * np.where(c, 1.0, 0.0), a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(out.grad * np.where(c, 0.0, 1.0), 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 * e)

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 / 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("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 reductions/reshape:

/app/submission/autograd.py

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

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:
            a._accum(_expand(out.grad, a.data.shape, axis, keepdims) / 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:
            g = _expand(out.grad, a.data.shape, axis, keepdims)
            mask = (a.data == m)
            counts = mask.sum(axis=axis, keepdims=True)
            a._accum(g * mask / 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 a.requires_grad:
            g = _expand(out.grad, a.data.shape, axis, keepdims)
            mask = (a.data == m)
            counts = mask.sum(axis=axis, keepdims=True)
            a._accum(g * mask / 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("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():
        start = 0
        for t, sz in zip(ts, sizes):
            sl = [slice(None)] * out.data.ndim
            sl[axis] = slice(start, start + sz)
            if t.requires_grad:
                t._accum(out.grad[tuple(sl)])
            start += 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():
        for i, t in enumerate(ts):
            sl = [slice(None)] * out.data.ndim
            sl[axis] = i
            if t.requires_grad:
                t._accum(out.grad[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
        ad, bd = a.data, b.data
        if a.requires_grad:
            ga = g @ np.swapaxes(bd, -1, -2)
            a._accum(_unbroadcast(ga, ad.shape))
        if b.requires_grad:
            gb = np.swapaxes(ad, -1, -2) @ g
            b._accum(_unbroadcast(gb, bd.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("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
            dot = (g * s).sum(axis=axis, keepdims=True)
            a._accum(s * (g - dot))

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 the extra activations:

/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 * (sig + a.data * sig * (1.0 - 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:
            a._accum(out.grad * np.where(x > 0.0, 1.0, al * ex))

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("hardtanh 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)

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("var backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            g = _expand(out.grad, a.data.shape, axis, keepdims)
            a._accum(g * 2.0 * (a.data - mu) / (n - ddof))

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:
            g = _expand(out.grad, a.data.shape, axis, keepdims)
            a._accum(g * (a.data - mu) / (n * skeep))

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:
            gf = np.flip(out.grad, axis=axis)
            rc = np.cumsum(gf, axis=axis)
            a._accum(np.flip(rc, axis=axis))

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 losses:

/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 - t) / 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("cross_entropy backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            logits._accum(out.grad * (sm - y) / 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("group_weighted_ce backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            logits._accum(out.grad * (sm - y) * scale[:, None])

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("reweighted_ce backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            logits._accum(out.grad * (sm - y) * (w / wsum)[:, None])

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("group_dro_loss backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            logits._accum(out.grad * (sm - y) * scale[:, None])

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("logit_adjusted_ce backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            logits._accum(out.grad * (sm - y) / 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("focal_loss backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            gam = g
            dfl_dp = gam * ((1.0 - p) ** (gam - 1.0)) * np.log(pc) - ((1.0 - p) ** gam) / pc
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            coef = (dfl_dp * p)[:, None]
            grad = coef * (y - sm)
            logits._accum(out.grad * grad / 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("irm_penalty backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            sdotx = (sm * x).sum(axis=-1, keepdims=True)
            inner = (sm - y) + sm * (x - sdotx)
            grad = 2.0 * grad_w * (1.0 / n) * inner
            logits._accum(out.grad * 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("gce_loss backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            coef = (-(pc ** qf))[:, None]
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            grad = coef * (y - sm)
            logits._accum(out.grad * grad / 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("vrex_penalty backward")  # TODO
+ added
    def _bw():
        if r.requires_grad:
            grad = (2.0 / K) * (rd - mu)
            r._accum(out.grad * grad.reshape(r.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("ldam_loss backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            y = np.zeros_like(sm)
            y[np.arange(n), t] = 1.0
            logits._accum(out.grad * sc * (sm - y) / 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("spectral_decoupling backward")  # TODO
+ added
    def _bw():
        if logits.requires_grad:
            logits._accum(out.grad * lm * x / 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)
Now normalization ops:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("layernorm backward")  # TODO
+ added
    def _bw():
        axes_red = tuple(range(out.grad.ndim - 1))
        if a.requires_grad:
            gy = out.grad * gamma.data
            mean_gy = gy.mean(-1, keepdims=True)
            mean_gyx = (gy * xhat).mean(-1, keepdims=True)
            a._accum(inv * (gy - mean_gy - xhat * mean_gyx))
        if gamma.requires_grad:
            gamma._accum((out.grad * xhat).sum(axis=axes_red))
        if beta.requires_grad:
            beta._accum(out.grad.sum(axis=axes_red))

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():
        if a.requires_grad:
            gy = out.grad * gamma.data
            mean_gy = gy.mean(0, keepdims=True)
            mean_gyx = (gy * xhat).mean(0, keepdims=True)
            a._accum(inv * (gy - mean_gy - xhat * mean_gyx))
        if gamma.requires_grad:
            gamma._accum((out.grad * xhat).sum(axis=0))
        if beta.requires_grad:
            beta._accum(out.grad.sum(axis=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("batchnorm2d backward")  # TODO
+ added
    def _bw():
        g_ = gamma.data.reshape(1, C, 1, 1)
        if gamma.requires_grad:
            gamma._accum((out.grad * xhat).sum(axis=(0, 2, 3)))
        if beta.requires_grad:
            beta._accum(out.grad.sum(axis=(0, 2, 3)))
        if x.requires_grad:
            gy = out.grad * g_
            if training:
                mean_gy = gy.mean(axis=(0, 2, 3), keepdims=True)
                mean_gyx = (gy * xhat).mean(axis=(0, 2, 3), keepdims=True)
                x._accum(inv * (gy - mean_gy - xhat * mean_gyx))
            else:
                x._accum(gy * 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("rms_norm backward")  # TODO
+ added
    def _bw():
        axes_red = tuple(range(out.grad.ndim - 1))
        if a.requires_grad:
            gy = out.grad * gamma.data
            sdot = (gy * x).sum(axis=-1, keepdims=True)
            a._accum(r * gy - (r ** 3 / D) * x * sdot)
        if gamma.requires_grad:
            gamma._accum((out.grad * xhat).sum(axis=axes_red))

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("groupnorm2d backward")  # TODO
+ added
    def _bw():
        if gamma.requires_grad:
            gamma._accum((out.grad * xhat).sum(axis=(0, 2, 3)))
        if beta.requires_grad:
            beta._accum(out.grad.sum(axis=(0, 2, 3)))
        if x.requires_grad:
            gy = out.grad * gamma.data.reshape(1, C, 1, 1)
            gyg = gy.reshape(N, G, m)
            xhatg = xc * inv
            mean_gy = gyg.mean(2, keepdims=True)
            mean_gyx = (gyg * xhatg).mean(2, keepdims=True)
            dxg = inv * (gyg - mean_gy - xhatg * mean_gyx)
            x._accum(dxg.reshape(N, C, H, W))

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 and pooling:

/app/submission/autograd.py

− removed
    def _bw():
        raise NotImplementedError("conv2d backward")  # TODO
+ added
    def _bw():
        g = out.grad.reshape(N, Cout, OH * OW)
        if weight.requires_grad:
            dWm = np.einsum("nop,nkp->ok", g, cols)
            weight._accum(dWm.reshape(Cout, Cin, kh, kw))
        if bias.requires_grad:
            bias._accum(g.sum(axis=(0, 2)))
        if x.requires_grad:
            dcols = np.einsum("ok,nop->nkp", Wm, g)
            dx = _col2im(dcols, x.data.shape, kh, kw, pad, st, OH, OW)
            x._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("maxpool2d backward")  # TODO
+ added
    def _bw():
        if x.requires_grad:
            g = out.grad
            outk = outd[:, :, :, None, :, None]
            mask = (xr == outk)
            counts = mask.sum(axis=(3, 5), keepdims=True)
            gg = g[:, :, :, None, :, None] * mask / counts
            x._accum(gg.reshape(N, C, H, W))

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("maxpool2d_stride backward")  # TODO
+ added
    def _bw():
        if x.requires_grad:
            g = out.grad
            outk = outd[:, :, None, None, :, :]
            mask = (win == outk)
            counts = mask.sum(axis=(2, 3), keepdims=True)
            contrib = mask * (g[:, :, None, None, :, :] / counts)
            dxp = np.zeros((N, C, Hp, Wp), dtype=np.float64)
            for i in range(k):
                for j in range(k):
                    dxp[:, :, i:i + st * OH:st, j:j + st * OW:st] += contrib[:, :, i, j]
            if pad:
                dx = dxp[:, :, pad:pad + H, pad:pad + W]
            else:
                dx = dxp
            x._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("avgpool2d backward")  # TODO
+ added
    def _bw():
        if x.requires_grad:
            g = out.grad
            gg = (g[:, :, :, None, :, None] * np.ones((1, 1, 1, k, 1, k))) / (k * k)
            x._accum(gg.reshape(N, C, H, W))

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("global_avg_pool backward")  # TODO
+ added
    def _bw():
        if x.requires_grad:
            g = out.grad[:, :, None, None] * np.ones((1, 1, H, W))
            x._accum(g / (H * W))

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 embedding and dropout:

/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 backward")  # TODO
+ added
        def _bw_id():
            if a.requires_grad:
                a._accum(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("dropout backward")  # TODO
+ added
    def _bw():
        if a.requires_grad:
            a._accum(out.grad * keep)

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 is complete. Let me run the autograd checks.

Run autograd grad checks

shell
OMP_NUM_THREADS=1 OPENBLAS_NUM_THREADS=1 MKL_NUM_THREADS=1 python3 run_checks.py --only autograd_grads 2>&1 | tail -40
output
grad/hardtanh                              OK    (max_abs=1.57e-11)
  grad/var_axis                              OK    (max_abs=3.14e-11)
  grad/std_axis                              OK    (max_abs=3.54e-11)
  grad/cumsum                                OK    (max_abs=1.14e-10)
  grad/maxpool2d_stride                      OK    (max_abs=7.86e-10)
  grad/layernorm_x                           OK  
  grad/batchnorm1d_x                         OK  
  grad/embedding                             OK  
  grad/mse_loss                              OK  
  grad/cross_entropy                         OK  
  grad/conv2d_x                              OK  
  grad/conv2d_weight                         OK  
  grad/conv2d_bias                           OK  
  grad/conv2d_x_pad0                         OK  
  grad/batchnorm2d_x                         OK  
  grad/batchnorm2d_gamma                     OK  
  grad/batchnorm2d_beta                      OK  
  grad/batchnorm2d_x_eval                    OK  
  grad/nn.Linear_x                           FAIL  (raised NotImplementedError: forward)
  grad/nn.Conv2d_x                           FAIL  (raised NotImplementedError: forward)
  grad/nn.LayerNorm_x                        FAIL  (raised NotImplementedError: forward)
  grad/nn.BatchNorm1d_x                      FAIL  (raised NotImplementedError: forward)
  grad/CNN_grad_classifier.weight            FAIL  (raised NotImplementedError: forward)
  grad/CNN_grad_embed.weight                 FAIL  (rai
…[truncated 1123 chars]
autograd done. Now let me implement nn.py forwards. I'll edit each method.

/app/submission/nn.py

− removed
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        d = {"weight": self.weight}
+ 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
    def named_params(self):
        d = {"weight": self.weight}

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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        return {"weight": self.weight, "bias": self.bias}
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.conv2d(x, self.weight, self.bias, pad=self.pad)
    def named_params(self):
        return {"weight": self.weight, "bias": self.bias}

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
    def forward(self, x: Tensor, training: bool = True) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        return {"gamma": self.gamma, "beta": self.beta}

    def buffers(self):
+ added
    def forward(self, x: Tensor, training: bool = True) -> Tensor:
        return ag.batchnorm2d(x, self.gamma, self.beta, self.running_mean, self.running_var,
                              training=training, momentum=self.momentum, eps=self.eps)
    def named_params(self):
        return {"gamma": self.gamma, "beta": self.beta}

    def buffers(self):

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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        return {"gamma": self.gamma, "beta": self.beta}


class LayerNorm(Module):
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.batchnorm(x, self.gamma, self.beta, eps=self.eps)
    def named_params(self):
        return {"gamma": self.gamma, "beta": self.beta}


class LayerNorm(Module):

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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        return {"gamma": self.gamma, "beta": self.beta}


class Dropout(Module):
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.layernorm(x, self.gamma, self.beta, eps=self.eps)
    def named_params(self):
        return {"gamma": self.gamma, "beta": self.beta}


class Dropout(Module):

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
    def forward(self, x: Tensor, training: bool = False, rng=None) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
+ added
    def forward(self, x: Tensor, training: bool = False, rng=None) -> Tensor:
        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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        return {}


class MaxPool2d(Module):
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.avgpool2d(x, self.k)
    def named_params(self):
        return {}


class MaxPool2d(Module):

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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self):
        return {}


class RMSNorm(Module):
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.maxpool2d(x, self.k)
    def named_params(self):
        return {}


class RMSNorm(Module):

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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.rms_norm). See the docstring/contract.
        raise NotImplementedError("forward")
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.rms_norm(x, self.gamma, eps=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
    def forward(self, x: Tensor) -> Tensor:
        # TODO: implement (compose ag.groupnorm2d). See the docstring/contract.
        raise NotImplementedError("forward")
+ added
    def forward(self, x: Tensor) -> Tensor:
        return ag.groupnorm2d(x, self.gamma, self.beta, self.num_groups, eps=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)
Now the models. ResidualConvNet:

/app/submission/nn.py

− removed
        # TODO: implement (stem->gn0->silu; then 2 residual blocks
        #   r=h; h=silu(b*n1(b*c1(h))); h=b*n2(b*c2(h)); h=silu(h + r);
        #   then strided downsample via ag.conv2d(h, down.weight, down.bias, pad=1, stride=2) + silu;
        #   then global-avg-pool over axes (2,3); then the linear head). Compose ag.* ops.
        raise NotImplementedError("forward")
+ added
        h = ag.silu(self.gn0(self.stem(X)))
        r = h
        h = ag.silu(self.b1n1(self.b1c1(h)))
        h = self.b1n2(self.b1c2(h))
        h = ag.silu(ag.add(h, r))
        r = h
        h = ag.silu(self.b2n1(self.b2c1(h)))
        h = self.b2n2(self.b2c2(h))
        h = ag.silu(ag.add(h, r))
        h = ag.silu(ag.conv2d(h, self.down.weight, self.down.bias, pad=1, stride=2))
        h = ag.global_avg_pool(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
    def featurize(self, X, training: bool = True) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("featurize")
    def forward(self, X, training: bool = True) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
+ added
    def featurize(self, X, training: bool = True) -> Tensor:
        h = ag.maxpool2d(ag.relu(self.bn1(self.conv1(X), training)), 2)
        h = ag.maxpool2d(ag.relu(self.bn2(self.conv2(h), training)), 2)
        h = ag.relu(self.bn3(self.conv3(h), training))
        h = ag.global_avg_pool(h)
        h = ag.relu(self.embed(h))
        return h
    def forward(self, X, training: bool = True) -> Tensor:
        return self.classifier(self.featurize(X, training))

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
    def forward(self, x) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self) -> Dict[str, Tensor]:
        d: Dict[str, Tensor] = {}
        for i, lin in enumerate(self.layers):
+ added
    def forward(self, x) -> Tensor:
        h = x
        n = len(self.layers)
        for i, lin in enumerate(self.layers):
            h = lin(h)
            if i < n - 1:
                h = ag.relu(h)
        return h
    def named_params(self) -> Dict[str, Tensor]:
        d: Dict[str, Tensor] = {}
        for i, lin in enumerate(self.layers):

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
    def forward(self, x) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self) -> Dict[str, Tensor]:
        d: Dict[str, Tensor] = {}
        for k, v in self.proj_in.named_params().items():
+ added
    def forward(self, x) -> Tensor:
        h = self.proj_in(x)
        for blk in self.blocks:
            n = blk["ln"](h)
            m = blk["fc2"](ag.gelu(blk["fc1"](n)))
            h = ag.add(h, m)
        return self.proj_out(h)
    def named_params(self) -> Dict[str, Tensor]:
        d: Dict[str, Tensor] = {}
        for k, v in self.proj_in.named_params().items():

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
    def forward(self, X, training: bool = True) -> Tensor:
        # TODO: implement (compose ag.* ops). See the docstring/contract.
        raise NotImplementedError("forward")
    def named_params(self) -> Dict[str, Tensor]:
        d: Dict[str, Tensor] = {}
        for name in ("conv1", "bn1", "conv2", "bn2", "head"):
+ added
    def forward(self, X, training: bool = True) -> Tensor:
        h = ag.maxpool2d(ag.relu(self.bn1(self.conv1(X), training)), 2)
        h = ag.avgpool2d(ag.relu(self.bn2(self.conv2(h), training)), 2)
        N = h.shape[0]
        h = ag.reshape(h, (N, 2 * self.W * self.side * self.side))
        return self.head(h)
    def named_params(self) -> Dict[str, Tensor]:
        d: Dict[str, Tensor] = {}
        for name in ("conv1", "bn1", "conv2", "bn2", "head"):

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 robustness helpers:

/app/submission/nn.py

− removed
    balanced-group / DFR weighting). If ``n_groups`` is None it is inferred as max(group_ids)+1."""
    # TODO: implement (numpy only). See docstring.
    raise NotImplementedError("balanced_group_weights")
+ added
    balanced-group / DFR weighting). If ``n_groups`` is None it is inferred as max(group_ids)+1."""
    gids = np.asarray(group_ids).astype(np.int64).reshape(-1)
    present = np.unique(gids)
    if n_groups is None:
        n_groups = int(gids.max()) + 1
    w = np.zeros(int(n_groups), dtype=np.float64)
    w[present] = 1.0 / len(present)
    return w

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
    effective number is (1-beta^n_c)/(1-beta) (Cui et al.); beta=0 reduces to inverse-frequency
    1/n_c. Each sample gets its class weight, and the vector is normalized to mean 1."""
    # TODO: implement (numpy only). See docstring.
    raise NotImplementedError("class_balanced_weights")
+ added
    effective number is (1-beta^n_c)/(1-beta) (Cui et al.); beta=0 reduces to inverse-frequency
    1/n_c. Each sample gets its class weight, and the vector is normalized to mean 1."""
    t = np.asarray(targets).astype(np.int64).reshape(-1)
    if n_classes is None:
        n_classes = int(t.max()) + 1
    counts = np.bincount(t, minlength=n_classes).astype(np.float64)
    if beta > 0.0:
        eff = (1.0 - beta ** counts) / (1.0 - beta)
    else:
        eff = counts.copy()
    clw = np.zeros(n_classes, dtype=np.float64)
    nz = counts > 0
    clw[nz] = 1.0 / eff[nz]
    w = clw[t]
    w = w / w.mean()
    return w

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
    vector. Empty classes get log(eps)."""
    # TODO: implement (numpy only). See docstring.
    raise NotImplementedError("log_class_prior")
+ added
    vector. Empty classes get log(eps)."""
    t = np.asarray(targets).astype(np.int64).reshape(-1)
    if n_classes is None:
        n_classes = int(t.max()) + 1
    counts = np.bincount(t, minlength=n_classes).astype(np.float64)
    N = t.size
    prior = counts / N
    lp = np.where(counts > 0, np.log(np.clip(prior, eps, None)), np.log(eps))
    return lp

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
    Returns a length-``n_classes`` vector."""
    # TODO: implement (numpy only). See docstring.
    raise NotImplementedError("ldam_margins")
+ added
    Returns a length-``n_classes`` vector."""
    t = np.asarray(targets).astype(np.int64).reshape(-1)
    if n_classes is None:
        n_classes = int(t.max()) + 1
    counts = np.bincount(t, minlength=n_classes).astype(np.float64)
    m = np.zeros(n_classes, dtype=np.float64)
    nz = counts > 0
    m[nz] = counts[nz] ** (-0.25)
    if m.max() > 0:
        m = m / m.max() * max_margin
    return m

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
    the PRESENT classes. Returns a length-``n_classes`` per-CLASS weight vector (NOT per-sample)."""
    # TODO: implement (numpy only). See docstring.
    raise NotImplementedError("effective_number_weights")
+ added
    the PRESENT classes. Returns a length-``n_classes`` per-CLASS weight vector (NOT per-sample)."""
    t = np.asarray(targets).astype(np.int64).reshape(-1)
    if n_classes is None:
        n_classes = int(t.max()) + 1
    counts = np.bincount(t, minlength=n_classes).astype(np.float64)
    w = np.zeros(n_classes, dtype=np.float64)
    nz = counts > 0
    eff = (1.0 - beta ** counts[nz]) / (1.0 - beta)
    w[nz] = 1.0 / eff
    w[nz] = w[nz] / w[nz].mean()
    return w

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
    def update(self, group_losses, present=None):
        # TODO: implement the masked EMA update (see docstring). Return self.l.copy().
        raise NotImplementedError("EMAGroupLoss.update")

    def worst_group(self):
        # TODO: implement (argmax of the current EMA). See docstring.
        raise NotImplementedError("EMAGroupLoss.worst_group")
+ added
    def update(self, group_losses, present=None):
        gl = np.asarray(group_losses, dtype=np.float64).reshape(-1)
        if present is None:
            mask = np.ones(self.n_groups, dtype=bool)
        else:
            mask = np.asarray(present, dtype=bool).reshape(-1)
        for k in range(self.n_groups):
            if not mask[k]:
                continue
            if not self._init[k]:
                self.l[k] = gl[k]
                self._init[k] = True
            else:
                self.l[k] = self.beta * self.l[k] + (1.0 - self.beta) * gl[k]
        return self.l.copy()

    def worst_group(self):
        return int(np.argmax(self.l))

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
    def update(self, group_losses):
        # TODO: exponentiated-gradient update of self.q on group_losses; renormalize.
        raise NotImplementedError("GroupDROState.update")
+ added
    def update(self, group_losses):
        gl = np.asarray(group_losses, dtype=np.float64).reshape(-1)
        self.q = self.q * np.exp(self.eta_q * gl)
        self.q = self.q / self.q.sum()
        return self.q.copy()

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 data.py:

/app/submission/data.py

− removed
    """Flatten (y, g) to a single group id y*n_classes + g (int64)."""
    # TODO
    raise NotImplementedError("group_ids")


def iterate(X, y, g, batch_size, rng):
    """Yield (Xb, yb, gb) minibatches over a random permutation of the dataset."""
    # TODO
    raise NotImplementedError("iterate")


def worst_group_acc(preds, y, g, n_classes) -> Tuple[float, float, Dict[int, float]]:
    """Return (min over (y,g) groups of within-group accuracy, average accuracy, per-group dict)."""
    # TODO
    raise NotImplementedError("worst_group_acc")


def stratified_group_split(y, g, n_classes, frac, rng) -> np.ndarray:
    """Boolean mask selecting ~frac of EACH (y,g) group (keeps both slices group-balanced)."""
    # TODO
    raise NotImplementedError("stratified_group_split")
+ added
    """Flatten (y, g) to a single group id y*n_classes + g (int64)."""
    return (np.asarray(y).astype(np.int64) * n_classes + np.asarray(g).astype(np.int64))


def iterate(X, y, g, batch_size, rng):
    """Yield (Xb, yb, gb) minibatches over a random permutation of the dataset."""
    N = X.shape[0]
    perm = rng.permutation(N)
    for start in range(0, N, batch_size):
        idx = perm[start:start + batch_size]
        yield X[idx], y[idx], g[idx]


def worst_group_acc(preds, y, g, n_classes) -> Tuple[float, float, Dict[int, float]]:
    """Return (min over (y,g) groups of within-group accuracy, average accuracy, per-group dict)."""
    preds = np.asarray(preds).reshape(-1)
    y = np.asarray(y).reshape(-1)
    g = np.asarray(g).reshape(-1)
    gid = group_ids(y, g, n_classes)
    correct = (preds == y).astype(np.float64)
    avg = float(correct.mean()) if correct.size else 0.0
    per: Dict[int, float] = {}
    for k in np.unique(gid):
        mask = gid == k
        per[int(k)] = float(correct[mask].mean())
    wga = min(per.values()) if per else 0.0
    return wga, avg, per


def stratified_group_split(y, g, n_classes, frac, rng) -> np.ndarray:
    """Boolean mask selecting ~frac of EACH (y,g) group (keeps both slices group-balanced)."""
    y = np.asarray(y).reshape(-1)
    g = np.asarray(g).reshape(-1)
    gid = group_ids(y, g, n_classes)
    mask = np.zeros(y.shape[0], dtype=bool)
    for k in np.unique(gid):
        idx = np.where(gid == k)[0]
        rng.shuffle(
…[truncated 165 chars]

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 optim.py. Let me implement all optimizers, clippers, and schedulers:

/app/submission/optim.py

− removed
    def step(self):
        # TODO: implement the SGD update (see module docstring). Update p.data in place.
        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
            if self.nesterov:
                upd = g + self.momentum * self._v[i]
            else:
                upd = 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: implement the Adagrad update (see module docstring). Update p.data in place.
        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: implement the RMSprop update (see module docstring). Update p.data in place.
        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: implement the Adam update (see module docstring). Update p.data in place.
        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: implement the AdamW update (see module docstring). Update p.data in place.
        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: implement the Adamax update (see module docstring). Update p.data in place.
        raise NotImplementedError("Adamax.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._u[i] = np.maximum(self.b2 * self._u[i], np.abs(g))
            p.data -= (self.lr / (1.0 - self.b1 ** self.t)) * self._m[i] / (self._u[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: implement the NAdam update (see module docstring). Update p.data in place.
        raise NotImplementedError("NAdam.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)
            mnes = self.b1 * mhat + (1.0 - self.b1) * g / (1.0 - self.b1 ** self.t)
            p.data -= self.lr * mnes / (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: implement the Lion update (see module docstring). Update p.data in place.
        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
    def step(self):
        # TODO: implement the RAdam update (see module docstring). Update p.data in place.
        raise NotImplementedError("RAdam.step")
+ added
    def step(self):
        self.t += 1
        t = self.t
        b1, b2 = self.b1, self.b2
        rinf = 2.0 / (1.0 - b2) - 1.0
        bc2 = 1.0 - b2 ** t
        rt = rinf - 2.0 * t * (b2 ** t) / bc2
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._m[i] = b1 * self._m[i] + (1.0 - b1) * g
            self._v[i] = b2 * self._v[i] + (1.0 - b2) * (g * g)
            mhat = self._m[i] / (1.0 - b1 ** t)
            if rt > 4.0:
                l = np.sqrt(bc2 / (self._v[i] + self.eps))
                r = math.sqrt(((rt - 4.0) * (rt - 2.0) * rinf) /
                              ((rinf - 4.0) * (rinf - 2.0) * rt))
                p.data -= self.lr * mhat * r * l
            else:
                p.data -= self.lr * mhat

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: implement the AdaBelief update (see module docstring). Update p.data in place.
        raise NotImplementedError("AdaBelief.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
            d = g - self._m[i]
            self._s[i] = self.b2 * self._s[i] + (1.0 - self.b2) * (d * d) + self.eps
            mhat = self._m[i] / (1.0 - self.b1 ** self.t)
            shat = self._s[i] / (1.0 - self.b2 ** self.t)
            p.data -= self.lr * (mhat / (np.sqrt(shat) + 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)
Now the clippers and schedulers:

/app/submission/optim.py

− removed
    exceeds ``max_norm`` every grad is scaled by ``max_norm / (total_norm + 1e-6)``."""
    # TODO: implement (see docstring).
    raise NotImplementedError("clip_grad_norm")
+ added
    exceeds ``max_norm`` every grad is scaled by ``max_norm / (total_norm + 1e-6)``."""
    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
    """Element-wise gradient clamp to [-clip_value, clip_value] (in place)."""
    # TODO: implement (see docstring).
    raise NotImplementedError("clip_grad_value")
+ added
    """Element-wise gradient clamp to [-clip_value, clip_value] (in place)."""
    for p in params:
        if p.grad is not None:
            p.grad = np.clip(p.grad, -clip_value, clip_value)

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
    ``total``. ``step`` is 0-based. Holds at ``min_lr`` past ``total``."""
    # TODO: implement (see docstring).
    raise NotImplementedError("cosine_lr")
+ added
    ``total``. ``step`` is 0-based. Holds at ``min_lr`` past ``total``."""
    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
    """Linear warmup to ``base_lr`` over ``warmup`` steps, then constant ``base_lr``."""
    # TODO: implement (see docstring).
    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)

/app/submission/optim.py

− removed
    """Step decay: lr = base_lr * gamma ** (step // step_size)."""
    # TODO: implement (see docstring).
    raise NotImplementedError("step_lr")
+ added
    """Step decay: lr = 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: lr = base_lr * gamma ** step."""
    # TODO: implement (see docstring).
    raise NotImplementedError("exponential_lr")
+ added
    """Exponential decay: lr = 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
    ``step >= total`` holds at ``min_lr``. ``step`` is 0-based."""
    # TODO: implement (see docstring).
    raise NotImplementedError("polynomial_lr")
+ added
    ``step >= total`` holds at ``min_lr``. ``step`` is 0-based."""
    if step >= total:
        return min_lr
    return (base_lr - min_lr) * ((1.0 - step / total) ** power) + min_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)

/app/submission/optim.py

− removed
    in-cycle step s: lr = min_lr + 0.5*(base_lr-min_lr)*(1+cos(pi*s/T)). ``step`` is 0-based."""
    # TODO: implement (see docstring).
    raise NotImplementedError("cosine_restart_lr")
+ added
    in-cycle step s: lr = min_lr + 0.5*(base_lr-min_lr)*(1+cos(pi*s/T)). ``step`` is 0-based."""
    s = step
    T_ = period
    while s >= T_:
        s -= T_
        T_ *= t_mult
    return min_lr + 0.5 * (base_lr - min_lr) * (1.0 + math.cos(math.pi * s / max(1, T_)))

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 let me run the full check suite:

Run full check suite

shell
OMP_NUM_THREADS=1 OPENBLAS_NUM_THREADS=1 MKL_NUM_THREADS=1 python3 run_checks.py 2>&1 | tail -25
output
robust/per_group_normalization_differs     OK    (diff=4.10e-02)
  robust/balanced_group_weights              OK    ([0.25 0.25 0.25 0.25])
  robust/class_balanced_weights              OK    (mean=1.000)
  robust/log_class_prior                     OK  
  robust/groupdro_state_upweights_worst      OK    (q=[0.221 0.33  0.233 0.216])

[robust2]  8/8
  robust2/gce_loss_grad                      OK  
  robust2/gce_loss_q03_grad                  OK  
  robust2/ldam_loss_grad                     OK  
  robust2/spectral_decoupling_grad           OK  
  robust2/vrex_penalty_grad                  OK  
  robust2/ldam_margins                       OK    ([0.319 0.42  0.5  ])
  robust2/effective_number_weights           OK    (mean=1.000)
  robust2/ema_group_loss_tracks_worst        OK    (l=[0.112 0.904 0.196])

[data]  3/3
  data/group_ids                             OK    ([ 1  4 11 14])
  data/worst_group_acc                       OK    (wga=0.00 avg=0.80)
  data/stratified_group_split                OK    (selected 33/60)

----------------------------------------------------------------------
autograd_grads 81/81 | nn_forward 21/21 | optim 21/21 | robust 13/13 | robust2 8/8 | data 3/3
TOTAL  147/147 public checks passing
All public checks pass. Now make sure model.npz clears the held-out worst-group accuracy threshold; the grader re-checks with DIFFERENT seeds.
All 147 public checks pass. Now let me inspect the dataset and write the training recipe.

Inspect dataset

shell
OMP_NUM_THREADS=1 python3 -c "
import numpy as np
d=np.load('data/train.npz'); X,y,g=d['X'],d['y'],d['g']
print('train X',X.shape,X.dtype,X.min(),X.max())
print('y vals',np.unique(y), 'counts',np.bincount(y))
print('g vals',np.unique(g),'counts',np.bincount(g))
nc=len(np.unique(y))
print('n_classes',nc,'img',X.shape[-1])
gid=y*nc+g
print('group counts',np.bincount(gid,minlength=nc*nc))
print('frac y==g', (y==g).mean())
r=np.load('data/reweight.npz'); Xr,yr,gr=r['X'],r['y'],r['g']
print('reweight X',Xr.shape,'counts gid',np.bincount(yr*nc+gr,minlength=nc*nc))
"
output
train X (2400, 3, 16, 16) float32 0.0 1.0
y vals [0 1 2 3] counts [600 600 600 600]
g vals [0 1 2 3] counts [604 593 603 600]
n_classes 4 img 16
group counts [585   1   7   7   6 580   3  11   3   5 586   6  10   7   7 576]
frac y==g 0.9695833333333334
reweight X (1280, 3, 16, 16) counts gid [80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80]
All public checks pass. Now let me write the training recipe.

/app/submission/train.py

− removed
from __future__ import annotations

import argparse
import json
import os
import sys

import numpy as np
+ added
from __future__ import annotations

import argparse
import json
import os
import sys

os.environ.setdefault("OMP_NUM_THREADS", "1")
os.environ.setdefault("OPENBLAS_NUM_THREADS", "1")
os.environ.setdefault("MKL_NUM_THREADS", "1")

import numpy as np

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

/app/submission/train.py

− removed
def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--train", default="/app/data/train.npz")
    ap.add_argument("--reweight", default="/app/data/reweight.npz")
    ap.add_argument("--out", default="/app/submission/model.npz")
    ap.add_argument("--seed", type=int, default=0)
    args = ap.parse_args()

    # TODO: build a SmallCNN(n_classes, img_size, width=WIDTH, embed_dim=EMBED_DIM), train a
    #       worst-group-robust recipe with your framework (forward -> loss -> backward -> clip ->
    #       optimizer step), then save:
    #           save_checkpoint(args.out, model.state_dict(), n_classes, img_size)
    raise NotImplementedError("implement training and call save_checkpoint")
+ added
def _logits_batched(model, X, bs=256, training=False):
    outs = []
    for s in range(0, X.shape[0], bs):
        outs.append(model(X[s:s + bs], training=training).data)
    return np.concatenate(outs, axis=0)


def evaluate(model, X, y, g, nc):
    logits = _logits_batched(model, X)
    preds = logits.argmax(axis=1)
    return D.worst_group_acc(preds, y, g, nc)


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--train", default="/app/data/train.npz")
    ap.add_argument("--reweight", default="/app/data/reweight.npz")
    ap.add_argument("--out", default="/app/submission/model.npz")
    ap.add_argument("--seed", type=int, default=0)
    args = ap.parse_args()

    rng = np.random.default_rng(args.seed)
    Xtr, ytr, gtr = D.load_npz(args.train)
    Xrw, yrw, grw = D.load_npz(args.reweight)
    nc = int(max(ytr.max(), yrw.max())) + 1
    img = Xtr.shape[-1]

    # Hold out part of the balanced reweight set for worst-group validation.
    val_mask = D.stratified_group_split(yrw, grw, nc, 0.25, np.random.default_rng(123))
    Xval, yval, gval = Xrw[val_mask], yrw[val_mask], grw[val_mask]
    Xrt, yrt, grt = Xrw[~val_mask], yrw[~val_mask], grw[~val_mask]

    model = SmallCNN(n_classes=nc, img_size=img, width=WIDTH, embed_dim=EMBED_DIM, seed=args.seed)

    # ---- Phase 1: ERM pretrain the whole net on the (correlated) train split for features. ----
    params = model.params()
    opt = O.AdamW(params, lr=2e-3, weight_decay=1e-4)
    n_epochs = 18
    steps_
…[truncated 2328 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)

Check end of train.py

shell
tail -8 /app/submission/train.py
output
if __name__ == "__main__":
    main()


if __name__ == "__main__":
    main()

/app/submission/train.py

− removed
if __name__ == "__main__":
    main()


if __name__ == "__main__":
    main()
+ added
if __name__ == "__main__":
    main()

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

Run training

shell
time OMP_NUM_THREADS=1 OPENBLAS_NUM_THREADS=1 MKL_NUM_THREADS=1 python3 submission/train.py 2>&1 | tail -20
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: 194/194 cases passed  (all milestones pass: True)
FINAL METRIC: worst-group accuracy = 0.75  < threshold 0.86

REWARD = 0   (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_58b8fa325cce4dd0. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_58b8fa325cce4dd0 · verifier authoritative; classifier explanatory.