SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

adv-robust-pgd

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.
SubtypeThreshold Slightly Missed
EvidenceComponent Conformance Suite: 201/201 cases passed (all milestones pass). FINAL METRIC: PGD robust accuracy = 0.5775 < threshold 0.6. The agent successfully implemented all framework components (autograd, convolution with col2im adjoint, all layers, optimizers, attack zoo, and all 10 adversarial training losses), passing every component check. The only failure is the robust accuracy metric falling 0.0225 points short of the 0.6 threshold.
Root causeThe agent correctly implemented the entire numpy-only deep learning framework and adversarial training pipeline, but the final model's robust accuracy (0.5775) fell just below the required threshold (0.6). This represents a narrow miss on the training-time hyperparameter selection (learning rate, number of steps, adversarial budget, loss weighting) rather than a framework or specification error.
RecommendationN/A - task is fine. The task is well-specified and correctly graded. The agent succeeded in all technical implementation aspects but needs better adversarial training hyperparameters (e.g., higher learning rate, more training steps, matched perturbation budget, or stronger loss weighting) to push robust accuracy over 0.6. This is expected difficulty for an adversarial robustness task.
Trajectory
Tool-by-tool agent trajectory
42 tool calls · 4 tool types · 61 steps
Agent session started, model: claude-opus-4-8 · 29 tools available · cwd: /app
I'll start by exploring the structure of the task and understanding the stub files.

List app structure

shell
ls -la && echo "---SUBMISSION---" && ls -la submission/ && echo "---DATA---" && ls -la data/ && echo "---CHECKS---" && wc -l run_checks.py test.sh 2>/dev/null
output
total 101
drwxr-xr-x  4 user user  4096 Jun 30 22:27 .
drwxr-xr-x 21 root root  4096 Jun 30 22:27 ..
-rw-r--r--  1 user user 14238 Jun 30 22:27 PROMPT.txt
-rw-r--r--  1 user user     5 Jun 30 22:27 agent.pid
-rw-r--r--  1 user user     0 Jun 30 22:27 agent.stderr
-rw-r--r--  1 user user  4629 Jun 30 22:27 agent_trajectory.jsonl
drwxr-xr-x  2 user user    60 Jun 30 22:27 data
-rw-r--r--  1 user user     0 Jun 30 22:27 run.log
-rwxr-xr-x  1 user user 57740 Jun 30 11:01 run_checks.py
drwxr-xr-x  2 user user   128 Jun 30 22:27 submission
-rwxr-xr-x  1 user user   998 Jun 30 11:01 test.sh
-rwxr-xr-x  1 user user   629 Jun 30 11:01 timer.sh
---SUBMISSION---
total 80
drwxr-xr-x 2 user user   128 Jun 30 22:27 .
drwxr-xr-x 4 user user  4096 Jun 30 22:27 ..
-rw-r--r-- 1 user user  5490 Jun 30 11:01 advtrain.py
-rw-r--r-- 1 user user  8776 Jun 30 11:01 attack.py
-rw-r--r-- 1 user user 18341 Jun 30 11:01 autograd.py
-rw-r--r-- 1 user user  2167 Jun 30 11:01 data.py
-rw-r--r-- 1 user user 15988 Jun 30 11:01 nn.py
-rw-r--r-- 1 user user  8853 Jun 30 11:01 optim.py
-rw-r--r-- 1 user user  3742 Jun 30 11:01 train.py
---DATA---
total 2904
drwxr-xr-x 2 user user      60 Jun 30 22:27 .
drwxr-xr-x 4 user user    4096 Jun 30 22:27 ..
-rw-r--r-- 1 user user 2967336 Jun 30 11:01 train.npz
---CHECKS---
 1187 run_checks.py
   19 test.sh
 1206 total
I'll read all the stub files to understand the structure and contracts.

/app/submission/autograd.py

/app/submission/nn.py

contents
1	"""Reverse-mode automatic differentiation over numpy arrays (IMPLEMENT THIS).
2	
3	A ``Tensor`` wraps a single ``numpy.ndarray`` (``float64``) and records the operation that
4	produced it so that ``.backward()`` can walk the graph in reverse-topological order and
5	accumulate ``.grad`` (the gradient of the scalar on which ``.backward()`` was called w.r.t.
6	this tensor) into every leaf.
7	
8	This task is ADVERSARIAL ROBUSTNESS: the model is a small convolutional classifier and the
9	attacks (PGD/FGSM/MI-FGSM/PGD-L2/CW) ascend on the gradient of an attack loss w.r.t. the INPUT
10	image, so the autograd engine must (a) flow gradients back to PARAMETERS (for training) AND
11	(b) flow gradients back to the INPUT tensor (for the attack). BOTH directions are exercised by the
12	verifier's finite-difference gradient checks, so the convolution's input-gradient (the ``_col2im``
13	adjoint) is load-bearing.
14	
15	Contract (the verifier's conformance suite differentiates your analytic backward against finite
16	differences and checks your forward against its own reference, so match this exactly):
17	
18	* ``Tensor(data, requires_grad=False)`` -- ``data`` is array-like, stored as ``float64`` in
19	  ``self.data``; ``self.grad`` starts as ``None`` and becomes a same-shape ``float64`` array after
20	  backward. ``requires_grad`` leaves accumulate grad; non-requiring leaves do not.
21	* Every op returns a NEW ``Tensor`` whose ``requires_grad`` is the OR of its differentiable inputs.
22	 
…[truncated 18629 chars]

contents
1	"""Neural-network layers + a small convolutional classifier, built on the autograd engine
2	(IMPLEMENT THE FORWARDS).
3	
4	Every module exposes ``params()`` -> list[Tensor] (the leaf tensors with ``requires_grad=True``)
5	and ``named_params()`` -> dict[str, Tensor] with STABLE names that match the checkpoint format the
6	verifier loads. ``SmallCNN.state_dict()`` / ``load_state_dict()`` round-trip a plain
7	``dict[str, np.ndarray]`` (saved as an ``.npz``); the verifier loads YOUR checkpoint into its OWN
8	reference SmallCNN via these names, so the names + shapes below are part of the contract.
9	
10	Naming contract for SmallCNN (do not change -- the verifier indexes by these exact keys):
11	  conv1.weight   (C1, C_in, 3, 3)        conv1.bias   (C1,)
12	  conv2.weight   (C2, C1, 3, 3)          conv2.bias   (C2,)
13	  fc1.weight     (C2*(H/4)*(W/4), F)      fc1.bias     (F,)
14	  fc2.weight     (F, n_classes)           fc2.bias     (n_classes,)
15	
16	Architecture (pinned): for an (N, C_in, H, W) input image batch,
17	  conv1 (C_in->C1, 3x3, pad 1) -> relu
18	  maxpool 2x2                   (H,W -> H/2,W/2)
19	  conv2 (C1->C2, 3x3, pad 1)   -> relu
20	  maxpool 2x2                   (H/2,W/2 -> H/4,W/4)
21	  flatten -> fc1 (-> F) -> relu -> fc2 (-> n_classes)   logits.
22	``Linear`` computes ``x @ weight + bias`` (weight is (in, out)). No BatchNorm inside SmallCNN (so
23	the attack runs a single deterministic eval-mode forward with no running-stat dependence).
24	
25	The other
…[truncated 15896 chars]
Now let me read the remaining stub files.

/app/submission/optim.py

contents
1	"""Optimizers + LR schedulers over a flat list of autograd ``Tensor`` parameters (IMPLEMENT THESE).
2	
3	Every optimizer operates IN PLACE on ``param.data`` using ``param.grad`` (the gradient accumulated
4	by ``Tensor.backward``). ``zero_grad()`` resets every grad to None. The EXACT update formula each
5	optimizer must match (the verifier checks one and several steps against its own reference) is in
6	its docstring.
7	
8	The adversarial-training loop uses AdamW (decoupled decay, with ``no_decay_ndim`` excluding 1-D
9	params/biases) + global grad-norm clipping; the rest of the optimizer zoo + the four LR schedulers
10	are part of the from-scratch framework the conformance suite audits.
11	"""
12	from __future__ import annotations
13	
14	import math
15	from typing import List
16	
17	import numpy as np
18	
19	from autograd import Tensor
20	
21	
22	class Optimizer:
23	    def __init__(self, params: List[Tensor]):
24	        self.params = list(params)
25	
26	    def zero_grad(self):
27	        for p in self.params:
28	            p.grad = None
29	
30	
31	class SGD(Optimizer):
32	    """SGD + momentum + optional Nesterov + (coupled/L2) weight decay:
33	        g = grad + wd*param;  v = mu*v + g;  step = (g + mu*v) if nesterov else v;  param -= lr*step."""
34	
35	    def __init__(self, params, lr=0.1, momentum=0.0, weight_decay=0.0, nesterov=False):
36	        super().__init__(params)
37	        self.lr = lr
38	        self.momentum = momentum
39	        self.weight_decay = weight
…[truncated 8125 chars]

/app/submission/data.py

contents
1	"""Data loading + minibatching for the shape-classification set (IMPLEMENT THESE).
2	
3	The visible train split ships as ``/app/data/train.npz`` with arrays ``X`` (N, C, H, W) float
4	pixels in [0,1] and ``y`` (N,) int labels. The SEALED held-out split is NOT in the image -- the
5	verifier regenerates it from a secret feature seed and runs its own attack on it.
6	
7	Contract:
8	  load_npz(path) -> (X float64 (N,C,H,W), y int64 (N,))
9	  train_val_split(X, y, val_frac, rng) -> ((Xtr,ytr),(Xval,yval))   random disjoint split (val slice
10	        is a held-BACK slice of the VISIBLE train data you may use for best-checkpoint selection --
11	        it is NOT the verifier's sealed held-out set)
12	  iter_batches(X, y, batch_size, rng) -> yields (xb, yb) random-permutation minibatches
13	  get_batch(X, y, batch_size, rng) -> a single random minibatch
14	  to_onehot(y, n_classes) -> (N, n_classes) one-hot float matrix
15	  clip01(X) -> X clamped into the [0,1] pixel domain
16	"""
17	from __future__ import annotations
18	
19	from typing import Iterator, Tuple
20	
21	import numpy as np
22	
23	
24	def load_npz(path: str) -> Tuple[np.ndarray, np.ndarray]:
25	    raise NotImplementedError("implement load_npz")
26	
27	
28	def train_val_split(X: np.ndarray, y: np.ndarray, val_frac: float,
29	                    rng: np.random.Generator):
30	    raise NotImplementedError("implement train_val_split")
31	
32	
33	def iter_batches(X: np.ndarray, y: np.ndarray, batch_size: int,
34	           
…[truncated 814 chars]

/app/submission/attack.py

contents
1	"""White-box evasion attacks built on the from-scratch autograd engine (IMPLEMENT THESE).
2	
3	An adversary perturbs each input within a norm budget (L-inf eps in the [0,1] pixel domain by
4	default) and tries to make the classifier WRONG. Every attack ascends on the gradient of an attack
5	loss with respect to the INPUT image, which is exactly the gradient the autograd engine produces
6	when the input is wrapped in a ``requires_grad=True`` Tensor and the loss is backpropagated -- so a
7	correct ``conv2d`` input-gradient (the ``_col2im`` adjoint) is load-bearing.
8	
9	THE PRIMITIVE
10	  input_grad(model, x, y)                  d/dx of mean cross-entropy of model(x) vs y (ndarray).
11	  loss_input_grad(model, x, y, loss_fn)    d/dx of an ARBITRARY scalar attack loss loss_fn(logits,y).
12	
13	L-INF ATTACKS
14	  fgsm(model, x, y, eps)                    clip(x + eps*sign(input_grad)).
15	  pgd_attack(model, x, y, eps, steps, alpha)  iterated FGSM with random start + project to the
16	                                            L-inf eps-ball around x AND the [0,1] box each step.
17	  mi_fgsm(model, x, y, eps, steps, alpha, mu) momentum-iterative FGSM: accumulate a decaying
18	                                            momentum of the L1-NORMALIZED gradient, step on its sign,
19	                                            project each step.
20	  targeted_pgd(model, x, y_target, eps, steps, alpha)  DESCEND CE toward y_target (step on the
21	                                     
…[truncated 7820 chars]

/app/submission/advtrain.py

contents
1	"""Adversarial-training objectives built on the from-scratch autograd engine (IMPLEMENT THESE).
2	
3	Several standard recipes turn a fragile classifier into a robust one. Each crafts adversarial
4	inputs per minibatch with the model's own attack, then takes a gradient step on a robustness-aware
5	loss; the recipes differ in the loss. All run a single forward+backward; the caller does grad-clip
6	+ the optimizer step. ``x_clean`` / ``x_adv`` are ndarrays (N, C, H, W); ``y`` is an int (N,).
7	
8	  pgd_at_loss(model, x_adv, y)                  Madry PGD-AT: CE on the ADVERSARIAL batch.
9	  trades_loss(model, x_clean, x_adv, y, beta)   TRADES: CE(clean) + beta*KL(stopgrad(clean)||adv).
10	                                                The clean branch INSIDE the KL is a STOP-GRADIENT
11	                                                target (detached): the KL backprops only through
12	                                                the adversarial branch.
13	  mart_loss(model, x_clean, x_adv, y, beta)     MART: boosted-CE on the adversarial batch
14	                                                ( CE(adv,y) - mean log(1 - max_{j!=y} p_adv_j) ) +
15	                                                beta * mean_i[ (1 - p_clean_i[y_i]) *
16	                                                KL_i(softmax(adv)||stopgrad softmax(clean)) ].
17	  alp_loss(model, x_clean, x_adv, y, lam)       Adversarial Logit Pairing:
18	                                                0.5*(CE(clean)+CE(ad
…[truncated 4278 chars]

/app/submission/train.py

contents
1	"""Adversarial-training loop for the small CNN, using the from-scratch numpy framework
2	(IMPLEMENT THIS).
3	
4	Standard (clean) training reaches ~99% CLEAN accuracy but ~chance ROBUST accuracy -- it is broken
5	by the verifier's STRONG multi-restart L-inf PGD attack. WEAK robust training is not enough either:
6	single-step (FGSM) adversarial training suffers "catastrophic overfitting" and is shattered by the
7	multi-step / multi-restart eval attack, and adversarial training at a SMALLER perturbation budget
8	than the eval budget leaves the model fragile exactly where it is attacked. The effective recipe is
9	full multi-step PGD ADVERSARIAL TRAINING (Madry et al. 2018) with the perturbation budget MATCHED
10	to the (larger) eval budget:
11	
12	  * on every minibatch, craft an inner k-step L-inf PGD adversarial batch against the CURRENT model
13	    (attack.pgd_attack), at the eps the eval uses, then take the AdamW step on advtrain.pgd_at_loss
14	    (cross-entropy on the adversarial batch);
15	  * train long enough for robustness to converge (a few epochs is not enough at this eps);
16	  * stability details that materially raise the achieved robust accuracy and make it reproducible:
17	    (a) exclude biases (1-D params) from weight decay (AdamW no_decay_ndim=1); (b) clip the global
18	    gradient norm (the adversarial loss surface is sharp); (c) keep the BEST-by-robust-accuracy
19	    checkpoint, evaluated each epoch with the model's own multi-step PGD on a held-BACK slic
…[truncated 2473 chars]
Let me look at the run_checks.py to understand the exact contracts and the data.

Inspect training data

shell
python3 -c "
import numpy as np
d=np.load('data/train.npz')
for k in d.files: print(k, d[k].shape, d[k].dtype)
print('y unique', np.unique(d['y']))
print('X range', d['X'].min(), d['X'].max())
print('N', d['X'].shape)
"
output
X (3600, 1, 16, 16) float32
y (3600,) int64
y unique [0 1 2 3 4 5]
X range 0.0 1.0
N (3600, 1, 16, 16)

/app/run_checks.py

contents
<system-reminder>[Truncated: PARTIAL view , showing lines 1-868 of 1188 total (29062 tokens, cap 25000). Call Read with offset=869 limit=868 for the next page, or Grep to find a specific section. Do NOT answer from this page alone if the answer may be further in the file.]</system-reminder>

1	#!/usr/bin/env python3
2	"""PUBLIC component check runner for the from-scratch numpy framework + the adversarial machinery.
3	
4	Run this AS OFTEN AS YOU LIKE while you implement to get a per-check progress signal:
5	
6	    python3 /app/run_checks.py                       # check the framework in /app/submission
7	    python3 /app/run_checks.py --submission /some/dir
8	    python3 /app/run_checks.py --only attack         # focus a single milestone
9	
10	It imports YOUR modules from /app/submission (autograd.py / nn.py / optim.py / data.py / attack.py
11	/ advtrain.py), exactly as the grader does, and runs a PUBLIC portion of the component conformance
12	suite, printing a clear per-check report. Each FAIL line names the exact op / layer / optimizer /
13	attack / adversarial-training property that is wrong.
14	
15	HOW THIS RELATES TO YOUR GRADE
16	------------------------------
17	This runner is a DEBUGGING AID, not the grader. It checks YOUR framework against self-consistent
18	references it computes on its OWN:
19	  * autograd_grads : central FINITE-DIFFERENCE of YOUR forward vs YOUR analytic backward (every op,
20	                     incl. the convolution input-gradient, the pools, an
…[truncated 44212 chars]
Let me read the rest of run_checks.py.

/app/run_checks.py

contents
869	    def dlr_loss_grad():
870	        rng = np.random.default_rng(sb + 60)
871	        x0 = rng.standard_normal((5, 4)); y = rng.integers(0, 4, size=5)
872	        lt = ag.Tensor(x0.copy(), requires_grad=True)
873	        atk.dlr_loss(lt, y).backward()
874	        gnum = _num_grad_input(lambda xv: np.array(float(atk.dlr_loss(ag.Tensor(xv), y).data)), x0.copy())
875	        return _max_abs(lt.grad, gnum) < TOL_GRAD, f"max_abs={_max_abs(lt.grad, gnum):.2e}"
876	
877	    def dlr_input_grad_fd():
878	        m = _model(61)
879	        x0 = np.random.default_rng(sb + 62).standard_normal((3, 1, 8, 8)); y = np.array([0, 1, 2])
880	        lf = lambda lg, t: atk.dlr_loss(lg, t)
881	        gan = np.asarray(atk.loss_input_grad(m, x0, y, lf), np.float64)
882	        gnum = _num_grad_input(lambda xv: np.array(float(lf(m(ag.Tensor(xv)), y).data)), x0.copy())
883	        return _max_abs(gan, gnum) < TOL_GRAD, f"max_abs={_max_abs(gan, gnum):.2e}"
884	
885	    def bim_stronger():
886	        m = _model(67)
887	        x = np.clip(np.random.default_rng(sb + 68).random((8, 1, 8, 8)), 0, 1); y = np.array([0, 1, 2, 3, 0, 1, 2, 3]); eps = 0.12
888	        xf = atk.fgsm(m, x, y, eps); xb = atk.bim(m, x, y, eps, 15, 0.025)
889	        lf = float(ag.cross_entropy(m(xf), y).data); lb = float(ag.cross_entropy(m(xb), y).data)
890	        return lb >= lf - 1e-6, f"fgsm={lf:.3f} bim={lb:.3f}"
891	
892	    def restarts_worst_case():
893	        m = _model(69)
894	        x = np.clip(np.random.default_
…[truncated 15653 chars]
Now I have a full understanding of all the contracts. Let me set up task tracking and start implementing. I'll begin with `autograd.py`, the foundation. I'll write it in pieces to stay under ARG_MAX.
write · /app/submission/autograd.py
"""Reverse-mode automatic differentiation over numpy arrays."""
from __future__ import annotations

import math
from typing import Callable, Iterable, List, Optional

import numpy as np

_erf = np.vectorize(math.erf)


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


def _unbroadcast(grad: np.ndarray, shape: tuple) -> np.ndarray:
    grad = np.asarray(grad, dtype=np.float64)
    while grad.ndim > len(shape):
        grad = grad.sum(axis=0)
    for i, s in enumerate(shape):
        if s == 1 and grad.shape[i] != 1:
            grad = grad.sum(axis=i, keepdims=True)
    return grad


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

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

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

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

    def zero_grad(self):
        self.grad = None

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

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

      
…[truncated 7719 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)

Append reductions and nonlinearities

shell
cat >> /app/submission/autograd.py << 'PYEOF'


# ===================================================================== reductions / reshape
def sum(a, axis=None, keepdims=False) -> Tensor:
    a = _ensure(a)
    out = Tensor(np.sum(a.data, axis=axis, keepdims=keepdims),
                 requires_grad=a.requires_grad, _parents=(a,))

    def _backward():
        if a.requires_grad:
            a._accum(_expand(out.grad, axis, keepdims, a.shape))
    out._backward = _backward
    return out


def mean(a, axis=None, keepdims=False) -> Tensor:
    a = _ensure(a)
    out = Tensor(np.mean(a.data, axis=axis, keepdims=keepdims),
                 requires_grad=a.requires_grad, _parents=(a,))
    axes = _reduce_axes(axis, a.data.ndim)
    n = 1
    for ax in axes:
        n *= a.data.shape[ax]

    def _backward():
        if a.requires_grad:
            a._accum(_expand(out.grad, axis, keepdims, a.shape) / n)
    out._backward = _backward
    return out


def max(a, axis=None, keepdims=False) -> Tensor:
    a = _ensure(a)
    val = np.max(a.data, axis=axis, keepdims=keepdims)
    out = Tensor(val, requires_grad=a.requires_grad, _parents=(a,))
    valk = np.max(a.data, axis=axis, keepdims=True)

    def _backward():
        if a.requires_grad:
            mask = (a.data == valk).astype(np.float64)
            counts = mask.sum(axis=axis, keepdims=True)
            a._accum(_expand(out.grad, axis, keepdims, a.shape) * mask / counts)
    out._backward = _backward
    return out


def mi
…[truncated 5762 chars]
output
done
Now let me append the losses, normalization, conv, pooling, and remaining ops.

Append losses, norm, embedding, dropout

shell
cat >> /app/submission/autograd.py << 'PYEOF'


# ===================================================================== losses
def mse_loss(pred, target) -> Tensor:
    pred = _ensure(pred)
    t = target.data if isinstance(target, Tensor) else _as_f64(target)
    diff = pred.data - t
    n = pred.data.size
    out = Tensor(np.mean(diff * diff), requires_grad=pred.requires_grad, _parents=(pred,))

    def _backward():
        if pred.requires_grad:
            pred._accum(out.grad * 2.0 * diff / n)
    out._backward = _backward
    return out


def _softmax_np(x, axis=-1):
    z = x - np.max(x, axis=axis, keepdims=True)
    e = np.exp(z)
    return e / np.sum(e, axis=axis, keepdims=True)


def cross_entropy(logits, targets) -> Tensor:
    logits = _ensure(logits)
    t = np.asarray(targets).astype(np.int64)
    x = logits.data
    n = x.shape[0]
    z = x - np.max(x, axis=-1, keepdims=True)
    lse = np.log(np.sum(np.exp(z), axis=-1, keepdims=True))
    logp = z - lse
    loss = -np.mean(logp[np.arange(n), t])
    out = Tensor(loss, requires_grad=logits.requires_grad, _parents=(logits,))
    sm = np.exp(logp)

    def _backward():
        if logits.requires_grad:
            grad = sm.copy()
            grad[np.arange(n), t] -= 1.0
            logits._accum(out.grad * grad / n)
    out._backward = _backward
    return out


def nll_per_sample(logits, targets) -> Tensor:
    logits = _ensure(logits)
    t = np.asarray(targets).astype(np.int64)
    x = logits.data
    n = x.sha
…[truncated 4746 chars]
output
done
Now the conv, pooling, and remaining ops.

Append conv, pool, reductions, pad2d

shell
cat >> /app/submission/autograd.py << 'PYEOF'


# ===================================================================== conv2d (im2col)
def _im2col(x, kh, kw):
    N, C, H, W = x.shape
    OH = H - kh + 1
    OW = W - kw + 1
    cols = np.zeros((N, C, kh, kw, OH, OW), dtype=np.float64)
    for i in range(kh):
        for j in range(kw):
            cols[:, :, i, j, :, :] = x[:, :, i:i + OH, j:j + OW]
    cols = cols.reshape(N, C * kh * kw, OH * OW)
    return cols, OH, OW


def _col2im(cols, xshape, kh, kw, pad):
    N, C, H, W = xshape
    Hp = H + 2 * pad
    Wp = W + 2 * pad
    OH = Hp - kh + 1
    OW = Wp - kw + 1
    cols = cols.reshape(N, C, kh, kw, OH, OW)
    xpad = np.zeros((N, C, Hp, Wp), dtype=np.float64)
    for i in range(kh):
        for j in range(kw):
            xpad[:, :, i:i + OH, j:j + OW] += cols[:, :, i, j, :, :]
    if pad > 0:
        return xpad[:, :, pad:pad + H, pad:pad + W]
    return xpad


def conv2d(x, weight, bias, pad: int = 1) -> Tensor:
    x = _ensure(x); weight = _ensure(weight); bias = _ensure(bias)
    rg = x.requires_grad or weight.requires_grad or bias.requires_grad
    N, C, H, W = x.data.shape
    Cout, Cin, kh, kw = weight.data.shape
    if pad > 0:
        xp = np.pad(x.data, ((0, 0), (0, 0), (pad, pad), (pad, pad)))
    else:
        xp = x.data
    cols, OH, OW = _im2col(xp, kh, kw)
    Wcol = weight.data.reshape(Cout, -1)
    o = np.einsum('oc,ncp->nop', Wcol, cols)
    o = o + bias.data[None, :, None]
    out = Tensor(o.reshap
…[truncated 5119 chars]
output
done
Now the additional nonlinearities and normalization:

Append extra nonlinearities and norms

shell
cat >> /app/submission/autograd.py << 'PYEOF'


# ===================================================================== additional nonlinearities
def softplus(a, beta: float = 1.0) -> Tensor:
    a = _ensure(a)
    x = a.data
    o = np.logaddexp(0.0, beta * x) / beta
    out = Tensor(o, requires_grad=a.requires_grad, _parents=(a,))

    def _backward():
        if a.requires_grad:
            sig = 1.0 / (1.0 + np.exp(-beta * x))
            a._accum(out.grad * sig)
    out._backward = _backward
    return out


def silu(a) -> Tensor:
    a = _ensure(a)
    x = a.data
    sig = 1.0 / (1.0 + np.exp(-x))
    out = Tensor(x * sig, requires_grad=a.requires_grad, _parents=(a,))

    def _backward():
        if a.requires_grad:
            a._accum(out.grad * (sig + x * sig * (1.0 - sig)))
    out._backward = _backward
    return out


def mish(a) -> Tensor:
    a = _ensure(a)
    x = a.data
    sp = np.logaddexp(0.0, x)
    tsp = np.tanh(sp)
    out = Tensor(x * tsp, requires_grad=a.requires_grad, _parents=(a,))

    def _backward():
        if a.requires_grad:
            sig = 1.0 / (1.0 + np.exp(-x))
            a._accum(out.grad * (tsp + x * sig * (1.0 - tsp * tsp)))
    out._backward = _backward
    return out


def elu(a, alpha: float = 1.0) -> Tensor:
    a = _ensure(a)
    x = a.data
    o = np.where(x > 0, x, alpha * (np.exp(x) - 1.0))
    out = Tensor(o, requires_grad=a.requires_grad, _parents=(a,))

    def _backward():
        if a.requires_grad:
            a._accum(
…[truncated 3207 chars]
output
lines: 1102
Now let me implement nn.py forwards:

Implement simple nn forwards

shell
cd /app/submission && python3 - << 'PYEOF'
import re
f='nn.py'
s=open(f).read()
repls = [
('''    def forward(self, x: Tensor) -> Tensor:
        """ag.conv2d(x, weight, bias, pad)."""
        raise NotImplementedError("implement Conv2d.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return ag.conv2d(x, self.weight, self.bias, self.pad)'''),
('''    def forward(self, x: Tensor) -> Tensor:
        """ag.maxpool2d(x, k)."""
        raise NotImplementedError("implement MaxPool2d.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return ag.maxpool2d(x, self.k)'''),
('''    def forward(self, x: Tensor) -> Tensor:
        """ag.avgpool2d(x, k)."""
        raise NotImplementedError("implement AvgPool2d.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return ag.avgpool2d(x, self.k)'''),
('''    def forward(self, x: Tensor) -> Tensor:
        """ag.matmul(x, weight) + bias."""
        raise NotImplementedError("implement Linear.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return ag.add(ag.matmul(x, self.weight), self.bias)'''),
('''    def forward(self, x: Tensor) -> Tensor:
        """ag.layernorm(x, weight, bias, eps)."""
        raise NotImplementedError("implement LayerNorm.forward")''',
'''    def forward(self, x: Tensor) -> Tensor:
        return ag.layernorm(x, self.weight, self.bias, self.eps)'''),
('''    def forward(self, x: Tensor) -> Tensor:
        """ag.batchnorm(x, weight, bias, eps)."""

…[truncated 1679 chars]
output
ok part1

Implement recurrent cells and CNNs

shell
python3 - << 'PYEOF'
f='nn.py'
s=open(f).read()
repls = [
('''    def forward(self, x: Tensor, h: Tensor) -> Tensor:
        """h' = tanh(x @ weight_ih^T + bias_ih + h @ weight_hh^T + bias_hh)."""
        raise NotImplementedError("implement RNNCell.forward")''',
'''    def forward(self, x: Tensor, h: Tensor) -> Tensor:
        pre = ag.add(ag.add(ag.matmul(x, ag.transpose(self.weight_ih)), self.bias_ih),
                     ag.add(ag.matmul(h, ag.transpose(self.weight_hh)), self.bias_hh))
        return ag.tanh(pre)'''),
('''    def forward(self, x: Tensor, h: Tensor) -> Tensor:
        """the GRU update above (slice the 3 gates out of the (N,3H) pre-activations)."""
        raise NotImplementedError("implement GRUCell.forward")''',
'''    def forward(self, x: Tensor, h: Tensor) -> Tensor:
        H = self.hidden_size
        gi = ag.add(ag.matmul(x, ag.transpose(self.weight_ih)), self.bias_ih)
        gh = ag.add(ag.matmul(h, ag.transpose(self.weight_hh)), self.bias_hh)
        i_r, i_z, i_n = gi[:, 0:H], gi[:, H:2 * H], gi[:, 2 * H:3 * H]
        h_r, h_z, h_n = gh[:, 0:H], gh[:, H:2 * H], gh[:, 2 * H:3 * H]
        r = ag.sigmoid(ag.add(i_r, h_r))
        z = ag.sigmoid(ag.add(i_z, h_z))
        n = ag.tanh(ag.add(i_n, ag.mul(r, h_n)))
        one = ag.Tensor(np.ones((1, H)))
        return ag.add(ag.mul(ag.sub(one, z), n), ag.mul(z, h))'''),
('''    def forward(self, x: Tensor, h: Tensor, c: Tensor):
        """the LSTM update above; return (h', c')."""
        raise No
…[truncated 1653 chars]
output
ok part2
Now let me run the autograd_grads, nn_forward, and data checks. First let me implement data.py:

/app/submission/data.py

− removed
def load_npz(path: str) -> Tuple[np.ndarray, np.ndarray]:
    raise NotImplementedError("implement load_npz")


def train_val_split(X: np.ndarray, y: np.ndarray, val_frac: float,
                    rng: np.random.Generator):
    raise NotImplementedError("implement train_val_split")


def iter_batches(X: np.ndarray, y: np.ndarray, batch_size: int,
                 rng: np.random.Generator) -> Iterator[Tuple[np.ndarray, np.ndarray]]:
    raise NotImplementedError("implement iter_batches")


def get_batch(X: np.ndarray, y: np.ndarray, batch_size: int,
              rng: np.random.Generator) -> Tuple[np.ndarray, np.ndarray]:
    """A single random minibatch (without replacement if possible). Shape-preserving."""
    raise NotImplementedError("implement get_batch")


def to_onehot(y: np.ndarray, n_classes: int) -> np.ndarray:
    """(N, n_classes) one-hot float matrix from integer labels y."""
    raise NotImplementedError("implement to_onehot")


def clip01(X: np.ndarray) -> np.ndarray:
    """Clamp X into the [0,1] pixel domain (the valid attack range)."""
    raise NotImplementedError("implement clip01")
+ added
def load_npz(path: str) -> Tuple[np.ndarray, np.ndarray]:
    d = np.load(path)
    X = np.asarray(d["X"], dtype=np.float64)
    y = np.asarray(d["y"], dtype=np.int64)
    return X, y


def train_val_split(X: np.ndarray, y: np.ndarray, val_frac: float,
                    rng: np.random.Generator):
    n = X.shape[0]
    perm = rng.permutation(n)
    nval = int(round(n * val_frac))
    vidx = perm[:nval]
    tidx = perm[nval:]
    return (X[tidx], y[tidx]), (X[vidx], y[vidx])


def iter_batches(X: np.ndarray, y: np.ndarray, batch_size: int,
                 rng: np.random.Generator) -> Iterator[Tuple[np.ndarray, np.ndarray]]:
    n = X.shape[0]
    perm = rng.permutation(n)
    for s in range(0, n, batch_size):
        idx = perm[s:s + batch_size]
        yield X[idx], y[idx]


def get_batch(X: np.ndarray, y: np.ndarray, batch_size: int,
              rng: np.random.Generator) -> Tuple[np.ndarray, np.ndarray]:
    """A single random minibatch (without replacement if possible). Shape-preserving."""
    n = X.shape[0]
    replace = batch_size > n
    idx = rng.choice(n, size=batch_size, replace=replace)
    return X[idx], y[idx]


def to_onehot(y: np.ndarray, n_classes: int) -> np.ndarray:
    """(N, n_classes) one-hot float matrix from integer labels y."""
    y = np.asarray(y).astype(np.int64)
    oh = np.zeros((y.shape[0], n_classes), dtype=np.float64)
    oh[np.arange(y.shape[0]), y] = 1.0
    return oh


def clip01(X: np.ndarray) -> np.ndarray:
    """Clamp X into the [0,1
…[truncated 75 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)

Run autograd grad checks

shell
cd /app && python3 run_checks.py --only autograd_grads 2>&1 | tail -40
output
grad/prod_axis                           OK    (max_abs=5.65e-10)
  grad/cumsum_ax1                          OK    (max_abs=3.79e-11)
  grad/logsumexp_ax1                       OK    (max_abs=4.93e-11)
  grad/pad2d                               OK    (max_abs=5.10e-11)
  grad/groupnorm_x                         OK  
  grad/rmsnorm_x                           OK  
  grad/layernorm_x                         OK  
  grad/batchnorm_x                         OK  
  grad/embedding                           OK  
  grad/mse_loss                            OK  
  grad/cross_entropy                       OK  
  grad/kl_div_q                            OK  
  grad/kl_div_p                            OK  
  grad/conv2d_input                        OK    (max_abs=1.09e-09)
  grad/conv2d_weight                       OK    (max_abs=3.38e-09)
  grad/conv2d_bias                         OK  
  grad/conv2d_pad0_input                   OK    (max_abs=7.79e-10)
  grad/maxpool2d                           OK  
  grad/avgpool2d                           OK  
  grad/nn.Conv2d_x                         OK  
  grad/nn.Linear_x                         OK  
  grad/nn.LayerNorm_x                      OK  
  grad/nn.BatchNorm1d_x                    OK  
  grad/cnn_grad_fc2.bias                   OK    (max_abs=1.21e-11)
  grad/cnn_grad_conv1.weight               OK    (max_abs=2.55e-11)
  grad/cnn_grad_conv2.weight               OK    (max_abs=2.61e-11)
  grad/cnn_grad_fc1.weight                 OK    (ma
…[truncated 815 chars]
All 82 autograd checks pass. Now let me implement the optimizers:

Implement and check optimizers

shell
python3 - << 'PYEOF'
f='/app/submission/optim.py'
s=open(f).read()
R=[
('''    def step(self):
        raise NotImplementedError("implement SGD.step")''',
'''    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._v[i] = self.momentum * self._v[i] + g
            v = self._v[i]
            step = (g + self.momentum * v) if self.nesterov else v
            p.data -= self.lr * step'''),
('''    def step(self):
        raise NotImplementedError("implement Adagrad.step")''',
'''    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._s[i] += g * g
            p.data -= self.lr * g / (np.sqrt(self._s[i]) + self.eps)'''),
('''    def step(self):
        raise NotImplementedError("implement RMSprop.step")''',
'''    def step(self):
        for i, p in enumerate(self.params):
            if p.grad is None:
                continue
            g = p.grad + self.weight_decay * p.data
            self._s[i] = self.alpha * self._s[i] + (1 - self.alpha) * (g * g)
            p.data -= self.lr * g / (np.sqrt(self._s[i]) + self.eps)'''),
('''    def step(self):
        raise NotImplementedError("implement Adam.step")''',
'''    def step(self):
        self.t += 1
        for i, p in enumerate(self.params):
            if p.grad 
…[truncated 5034 chars]
output
ok optim
[optim]  20/20
  optim/SGD_1step                          OK    (max_abs=0.0e+00)
  optim/SGD_momentum_5step                 OK    (max_abs=0.0e+00)
  optim/SGD_nesterov_5step                 OK    (max_abs=0.0e+00)
  optim/Adagrad_5step                      OK    (max_abs=0.0e+00)
  optim/RMSprop_5step                      OK    (max_abs=0.0e+00)
  optim/Adam_10step_wd                     OK    (max_abs=0.0e+00)
  optim/AdamW_10step_wd                    OK    (max_abs=0.0e+00)
  optim/Adamax_8step                       OK    (max_abs=0.0e+00)
  optim/NAdam_8step                        OK    (max_abs=0.0e+00)
  optim/Lion_8step_wd                      OK    (max_abs=0.0e+00)
  optim/Adadelta_8step                     OK    (max_abs=0.0e+00)
  optim/clip_grad_norm_clips               OK    (max_abs=0.0e+00)
  optim/clip_grad_norm_noop                OK    (max_abs=0.0e+00)
  optim/clip_grad_value                    OK    (max_abs=0.0e+00)
  optim/sched_cosine_lr                    OK    (match)
  optim/sched_warmup_lr                    OK    (match)
  optim/sched_step_lr                      OK    (match)
  optim/sched_exponential_lr               OK    (match)
  optim/sched_polynomial_lr                OK    (match)
  optim/sched_linear_lr                    OK    (match)

------------------------------------------------------------------------
optim 20/20
TOTAL  20/20 public checks passing
All public checks pass. Now make sure model.npz clears the held-out ROBUST-
…[truncated 90 chars]
All optim pass. Now attack.py:
write · /app/submission/attack.py
"""White-box evasion attacks built on the from-scratch autograd engine."""
from __future__ import annotations

from typing import Callable, Optional, Tuple

import numpy as np

import autograd as ag
from autograd import Tensor


def loss_input_grad(model, x: np.ndarray, y: np.ndarray,
                    loss_fn: Callable[[Tensor, np.ndarray], Tensor]) -> np.ndarray:
    xt = Tensor(np.asarray(x, dtype=np.float64), requires_grad=True)
    logits = model(xt)
    loss = loss_fn(logits, y)
    loss.backward()
    return np.asarray(xt.grad, dtype=np.float64)


def input_grad(model, x: np.ndarray, y: np.ndarray) -> np.ndarray:
    return loss_input_grad(model, x, y, lambda lg, t: ag.cross_entropy(lg, t))


def _other_max(logits, y):
    N, C = logits.shape
    mask = np.zeros((N, C), dtype=np.float64)
    mask[np.arange(N), np.asarray(y).astype(np.int64)] = -1e30
    masked = ag.add(logits, Tensor(mask))
    return ag.max(masked, axis=1)


def cw_margin_loss(logits, y, kappa: float = 0.0) -> Tensor:
    logits = ag._ensure(logits)
    N = logits.shape[0]
    idx = (np.arange(N), np.asarray(y).astype(np.int64))
    true = ag.getitem(logits, idx)
    other = _other_max(logits, y)
    margin = ag.sub(true, other)
    neg_margin = ag.mul(margin, -1.0)
    capped = ag.maximum(neg_margin, Tensor(np.full(N, -kappa)))
    return ag.mean(capped)


def dlr_loss(logits, y, eps: float = 1e-12) -> Tensor:
    logits = ag._ensure(logits)
    N = logits.shape[0]
    idx = (np.arange(N), np.asarr
…[truncated 7400 chars]

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

Run attack checks

shell
python3 run_checks.py --only attack 2>&1 | tail -25
output
[attack]  18/18
  attack/input_grad_fd                     OK    (max_abs=2.73e-11)
  attack/cw_loss_input_grad_fd             OK    (max_abs=4.13e-12)
  attack/dlr_loss_grad                     OK    (max_abs=1.04e-09)
  attack/dlr_loss_input_grad_fd            OK    (max_abs=3.51e-11)
  attack/fgsm_step                         OK  
  attack/pgd_projection                    OK  
  attack/mi_fgsm_projection                OK  
  attack/cw_pgd_projection                 OK  
  attack/pgd_l2_projection                 OK  
  attack/bim_projection                    OK  
  attack/rfgsm_projection                  OK  
  attack/ni_fgsm_projection                OK  
  attack/pgd_restarts_projection           OK  
  attack/dlr_pgd_projection                OK  
  attack/pgd_stronger_than_fgsm            OK    (fgsm=1.450 pgd=1.469)
  attack/bim_stronger_than_fgsm            OK    (fgsm=1.411 bim=1.423)
  attack/pgd_restarts_worst_case           OK    (single=1.521 restarts=1.525)
  attack/targeted_pgd_lowers_target_ce     OK    (1.388->1.333)

------------------------------------------------------------------------
attack 18/18
TOTAL  18/18 public checks passing
All public checks pass. Now make sure model.npz clears the held-out ROBUST-accuracy threshold; the grader re-checks with DIFFERENT seeds/shapes + its OWN strong PGD.
Now advtrain.py:

/app/submission/advtrain.py

− removed
def pgd_at_loss(model, x_adv: np.ndarray, y: np.ndarray) -> Tensor:
    """Madry PGD-AT loss: cross-entropy on the adversarial batch (trains parameters)."""
    raise NotImplementedError("implement pgd_at_loss")


def trades_loss(model, x_clean: np.ndarray, x_adv: np.ndarray, y: np.ndarray,
                beta: float = 6.0) -> Tuple[Tensor, Dict[str, float]]:
    """TRADES loss = CE(clean, y) + beta * KL(stopgrad(softmax(clean)) || softmax(adv))."""
    raise NotImplementedError("implement trades_loss")


def mart_loss(model, x_clean: np.ndarray, x_adv: np.ndarray, y: np.ndarray,
              beta: float = 5.0) -> Tuple[Tensor, Dict[str, float]]:
    """MART loss (boosted CE on adv + misclassification-aware weighted KL with the clean target
    DETACHED); see the module docstring for the exact form."""
    raise NotImplementedError("implement mart_loss")


def alp_loss(model, x_clean: np.ndarray, x_adv: np.ndarray, y: np.ndarray,
             lam: float = 0.5) -> Tuple[Tensor, Dict[str, float]]:
    """Adversarial Logit Pairing: 0.5*(CE(clean)+CE(adv)) + lam*mean||z_clean - z_adv||^2 (no detach)."""
    raise NotImplementedError("implement alp_loss")


def label_smoothed_ce(logits, y, eps_ls: float = 0.1, n_classes: int = None) -> Tensor:
    """CE against a label-smoothed target ((1-eps_ls)*onehot + eps_ls/C*uniform), via log_softmax."""
    raise NotImplementedError("implement label_smoothed_ce")


def robust_ce_loss(model, x_clean: np.ndarray, x_adv: np.ndarray, y: np.nd
…[truncated 1782 chars]
+ added
def _detach(t: Tensor) -> Tensor:
    return Tensor(t.data.copy())


def pgd_at_loss(model, x_adv: np.ndarray, y: np.ndarray) -> Tensor:
    """Madry PGD-AT loss: cross-entropy on the adversarial batch (trains parameters)."""
    return ag.cross_entropy(model(Tensor(np.asarray(x_adv, np.float64))), y)


def trades_loss(model, x_clean: np.ndarray, x_adv: np.ndarray, y: np.ndarray,
                beta: float = 6.0) -> Tuple[Tensor, Dict[str, float]]:
    """TRADES loss = CE(clean, y) + beta * KL(stopgrad(softmax(clean)) || softmax(adv))."""
    cl = model(Tensor(np.asarray(x_clean, np.float64)))
    ad = model(Tensor(np.asarray(x_adv, np.float64)))
    ce = ag.cross_entropy(cl, y)
    tgt = _detach(cl)
    kl = ag.kl_div(tgt, ad)
    loss = ag.add(ce, ag.mul(kl, float(beta)))
    return loss, {"ce": float(ce.data), "kl": float(kl.data), "loss": float(loss.data)}


def mart_loss(model, x_clean: np.ndarray, x_adv: np.ndarray, y: np.ndarray,
              beta: float = 5.0) -> Tuple[Tensor, Dict[str, float]]:
    """MART loss (boosted CE on adv + misclassification-aware weighted KL with the clean target
    DETACHED); see the module docstring for the exact form."""
    yi = np.asarray(y).astype(np.int64)
    cl = model(Tensor(np.asarray(x_clean, np.float64)))
    ad = model(Tensor(np.asarray(x_adv, np.float64)))
    N, C = ad.shape
    # boosted CE on adversarial batch
    ce_adv = ag.cross_entropy(ad, yi)
    pa = ag.softmax(ad, axis=1)
    mask = np.zeros((N, C), dtype=np.float
…[truncated 4469 chars]

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

Run advtrain, integration, data, nn checks

shell
python3 run_checks.py --only advtrain 2>&1 | tail -20 && echo "===INTEG===" && python3 run_checks.py --only integration 2>&1 | tail -8 && echo "===DATA===" && python3 run_checks.py --only data 2>&1 | tail -6 && echo "===NN===" && python3 run_checks.py --only nn_forward 2>&1 | tail -5
output
[advtrain]  14/14
  advtrain/at_param_grad                   OK    (max_abs=2.56e-11)
  advtrain/trades_param_grad               OK    (max_abs=5.66e-04)
  advtrain/mart_param_grad                 OK    (max_abs=1.14e-04)
  advtrain/alp_param_grad                  OK    (max_abs=2.60e-11)
  advtrain/robust_ce_param_grad            OK    (max_abs=5.12e-11)
  advtrain/clp_param_grad                  OK    (max_abs=2.84e-05)
  advtrain/kl_at_param_grad                OK    (max_abs=1.62e-03)
  advtrain/logit_squeeze_param_grad        OK    (max_abs=4.80e-11)
  advtrain/ls_at_param_grad                OK    (max_abs=2.76e-11)
  advtrain/label_smoothed_ce_grad          OK  
  advtrain/trades_stopgrad                 OK    (max_abs=0.00e+00)
  advtrain/alp_pairing                     OK    (max_abs=0.00e+00)
  advtrain/clp_stopgrad                    OK    (max_abs=0.00e+00)
  advtrain/kl_at_stopgrad                  OK    (max_abs=0.00e+00)

------------------------------------------------------------------------
advtrain 14/14
TOTAL  14/14 public checks passing
All public checks pass. Now make sure model.npz clears the held-out ROBUST-accuracy threshold; the grader re-checks with DIFFERENT seeds/shapes + its OWN strong PGD.
===INTEG===
  integration/pgd_at_decreases             OK    (1.4247->1.3885)
  integration/trades_finite                OK    (1.393->1.337)
  integration/trades_decreases             OK    (1.3933->1.3367)

---------------------------------------------------
…[truncated 878 chars]
All milestones pass. Let me run the full suite to confirm:

Run full checks and smoke test

shell
python3 run_checks.py 2>&1 | tail -5; echo "EXIT: $?"; echo "=== smoke ==="; bash test.sh 2>&1 | tail -15
output
------------------------------------------------------------------------
autograd_grads 82/82 | nn_forward 22/22 | optim 20/20 | attack 18/18 | advtrain 14/14 | integration 4/4 | data 3/3
TOTAL  163/163 public checks passing
All public checks pass. Now make sure model.npz clears the held-out ROBUST-accuracy threshold; the grader re-checks with DIFFERENT seeds/shapes + its OWN strong PGD.
EXIT: 0
=== smoke ===
train.npz: X(3600, 1, 16, 16) float32  y(3600,)  classes=6
submission stubs present: ['__pycache__', 'advtrain.py', 'attack.py', 'autograd.py', 'data.py', 'nn.py', 'optim.py', 'train.py']
numpy 2.2.6
app_test smoke OK (run 'python3 /app/run_checks.py' for the per-check progress report)
All 163 public checks pass. Now Part B , implement the training loop and train the robust model. Let me implement `train.py`:

/app/submission/train.py

− removed
def train(train_path, out_path, epochs=12, batch_size=128, lr=1.2e-3, eps=0.12,
          at_steps=7, alpha=0.03, grad_clip=1.0, weight_decay=5e-4, val_frac=0.15,
          sel_steps=7, seed=0, log_every=1):
    """Run multi-step PGD adversarial training and save the best-by-robust-val checkpoint to
    ``out_path``. See the module docstring for the recipe."""
    raise NotImplementedError("implement the adversarial-training loop")
+ added
def _robust_acc(model, X, y, eps, steps, alpha, seed, restarts=1, max_n=512):
    n = min(max_n, X.shape[0])
    Xs, ys = X[:n], y[:n]
    correct = np.ones(n, dtype=bool)
    # clean correctness
    clean_pred = np.argmax(model(Xs).data, axis=1)
    correct &= (clean_pred == ys)
    for r in range(restarts):
        rng = np.random.default_rng(seed + 7919 * (r + 1))
        xadv = A.pgd_attack(model, Xs, ys, eps, steps, alpha, rng=rng)
        pred = np.argmax(model(xadv).data, axis=1)
        correct &= (pred == ys)
    return float(np.mean(correct))


def train(train_path, out_path, epochs=30, batch_size=128, lr=1.2e-3, eps=0.12,
          at_steps=10, alpha=0.03, grad_clip=1.0, weight_decay=5e-4, val_frac=0.12,
          sel_steps=20, seed=0, log_every=1):
    """Run multi-step PGD adversarial training and save the best-by-robust-val checkpoint."""
    X, y = D.load_npz(train_path)
    n_classes = int(y.max()) + 1
    c_in, img = X.shape[1], X.shape[2]
    rng = np.random.default_rng(seed)
    (Xtr, ytr), (Xval, yval) = D.train_val_split(X, y, val_frac, rng)

    model = SmallCNN(n_classes=n_classes, c_in=c_in, img=img, c1=C1, c2=C2, ff=FF, seed=seed)
    opt = O.AdamW(model.params(), lr=lr, betas=(0.9, 0.999),
                  weight_decay=weight_decay, no_decay_ndim=1)

    best_sd = model.state_dict()
    best_racc = -1.0
    step = 0
    total_steps = epochs * ((len(Xtr) + batch_size - 1) // batch_size)
    for ep in range(epochs):
        for xb, yb in D.iter_batche
…[truncated 1407 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 time a quick 2-epoch run to gauge speed and robustness signal:

Time 2-epoch training run

shell
cd /app/submission && time python3 -c "
import time, numpy as np
import train as Tr
sd, racc = Tr.train('/app/data/train.npz', '/tmp/test_model.npz', epochs=2, at_steps=10, sel_steps=20)
" 2>&1 | tail -10
output
real	0m1.295s
user	0m1.584s
sys	0m0.270s

Debug 2-epoch run

shell
python3 -c "
import train as Tr
sd, racc = Tr.train('/app/data/train.npz', '/tmp/test_model.npz', epochs=2, at_steps=10, sel_steps=20)
print('done', racc)
" 2>&1 | tail -10
output
(Bash completed with no output)

Run train.py main 2 epochs

shell
python3 train.py --epochs 2 --at-steps 10 2>&1 | tail -20
output
(Bash completed with no output)

Run train capturing to file

shell
python3 train.py --epochs 2 --at-steps 10 > /tmp/tr.log 2>&1; echo "exit=$?"; cat /tmp/tr.log
output
/bin/bash: line 1:  1543 Killed                  python3 train.py --epochs 2 --at-steps 10 > /tmp/tr.log 2>&1
exit=137

Check memory

shell
free -m; echo "---"; ulimit -a | grep -i mem
output
total        used        free      shared  buff/cache   available
Mem:             481         255         176           1          63         226
Swap:              0           0           0
---
max locked memory           (kbytes, -l) 8192
max memory size             (kbytes, -m) unlimited
virtual memory              (kbytes, -v) unlimited
Memory is very tight (481MB total). Let me profile memory of a single training step:

Profile single step memory

shell
/usr/bin/time -v python3 -c "
import numpy as np, data as D, attack as A, advtrain as AT, optim as O
from nn import SmallCNN
X,y=D.load_npz('/app/data/train.npz')
m=SmallCNN(n_classes=6,c_in=1,img=16,c1=14,c2=28,ff=96,seed=0)
opt=O.AdamW(m.params(),lr=1e-3,no_decay_ndim=1)
xb,yb=X[:128],y[:128]
rng=np.random.default_rng(0)
for s in range(5):
    xa=A.pgd_attack(m,xb,yb,0.12,10,0.03,rng=rng)
    loss=AT.pgd_at_loss(m,xa,yb)
    opt.zero_grad(); loss.backward(); O.clip_grad_norm(m.params(),1.0); opt.step()
    print('step',s,float(loss.data))
" 2>&1 | grep -E "step|Maximum resident|Killed"
output
(Bash completed with no output)

Test single PGD attack

shell
python3 -c "
import numpy as np, data as D, attack as A, advtrain as AT, optim as O
from nn import SmallCNN
X,y=D.load_npz('/app/data/train.npz')
m=SmallCNN(n_classes=6,c_in=1,img=16,c1=14,c2=28,ff=96,seed=0)
xb,yb=X[:128],y[:128]
rng=np.random.default_rng(0)
xa=A.pgd_attack(m,xb,yb,0.12,10,0.03,rng=rng)
print('pgd ok', xa.shape)
" 2>&1 ; echo "exit=$?"
output
/bin/bash: line 19:  1561 Killed                  python3 -c "
import numpy as np, data as D, attack as A, advtrain as AT, optim as O
from nn import SmallCNN
X,y=D.load_npz('/app/data/train.npz')
m=SmallCNN(n_classes=6,c_in=1,img=16,c1=14,c2=28,ff=96,seed=0)
xb,yb=X[:128],y[:128]
rng=np.random.default_rng(0)
xa=A.pgd_attack(m,xb,yb,0.12,10,0.03,rng=rng)
print('pgd ok', xa.shape)
" 2>&1
exit=137

Test forward/backward at various batch sizes

shell
python3 -c "
import numpy as np, data as D
from nn import SmallCNN
import autograd as ag
X,y=D.load_npz('/app/data/train.npz')
m=SmallCNN(n_classes=6,c_in=1,img=16,c1=14,c2=28,ff=96,seed=0)
for bs in [8,32,64,128]:
    xb=X[:bs]
    xt=ag.Tensor(xb,requires_grad=True)
    l=ag.cross_entropy(m(xt),y[:bs])
    l.backward()
    print('bs',bs,'ok')
" 2>&1; echo "exit=$?"
output
bs 8 ok
bs 32 ok
bs 64 ok
bs 128 ok
exit=0

Track RSS over manual PGD steps

shell
python3 -c "
import numpy as np, data as D, resource
from nn import SmallCNN
import autograd as ag
X,y=D.load_npz('/app/data/train.npz')
m=SmallCNN(n_classes=6,c_in=1,img=16,c1=14,c2=28,ff=96,seed=0)
xb=X[:128].copy(); yb=y[:128]
for s in range(12):
    xt=ag.Tensor(xb,requires_grad=True)
    l=ag.cross_entropy(m(xt),yb)
    l.backward()
    xb=xb+0.01*np.sign(xt.grad)
    rss=resource.getrusage(resource.RUSAGE_SELF).ru_maxrss/1024
    print('step',s,'maxrss_MB=%.1f'%rss)
" 2>&1; echo "exit=$?"
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: 201/201 cases passed  (all milestones pass: True)
FINAL METRIC: PGD robust accuracy = 0.5775  < threshold 0.6

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_c1ae8806a94c4d6b. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_c1ae8806a94c4d6b · verifier authoritative; classifier explanatory.