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.
SubtypeIncomplete Understanding / Hyperparameter Tuning
EvidenceTest output: 'COMPONENT CONFORMANCE SUITE: 201/201 cases passed (all milestones pass: True)' but 'FINAL METRIC: PGD robust accuracy = 0.5825 < threshold 0.6'. The agent's framework passed every single correctness check (all autograd ops, conv gradients, TRADES stop-gradient semantics, all attacks and adversarial-training losses), but the trained model fell short of the robust-accuracy threshold by 0.0175 (97.5% of target). This indicates correct implementation but insufficient training robustness.
Root causeThe agent correctly implemented the entire numpy deep-learning framework from scratch (all 201 conformance checks passed), but the final trained checkpoint did not reach the required robust-accuracy threshold (0.5825 vs 0.6). This is a training strategy/hyperparameter issue, not a specification or framework correctness problem.
RecommendationN/A - task is fine. The task specification is clear and correct. The agent came very close (97.5% of threshold) and failed due to training decisions (hyperparameter choices, insufficient training duration, or mismatch between training-time and eval-time attack budgets/parameters), not task ambiguity or underspecification.
Trajectory
Tool-by-tool agent trajectory
41 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 and understanding what's there.
shell
ls -la && echo "---SUBMISSION---" && ls -la submission/ && echo "---DATA---" && ls -la data/ 2>/dev/null
output
total 101
drwxr-xr-x  4 user user  4096 Jun 30 22:29 .
drwxr-xr-x 21 root root  4096 Jun 30 22:28 ..
-rw-r--r--  1 user user 14238 Jun 30 22:29 PROMPT.txt
-rw-r--r--  1 user user     5 Jun 30 22:29 agent.pid
-rw-r--r--  1 user user     0 Jun 30 22:29 agent.stderr
-rw-r--r--  1 user user  4476 Jun 30 22:29 agent_trajectory.jsonl
drwxr-xr-x  2 user user    60 Jun 30 22:29 data
-rw-r--r--  1 user user     0 Jun 30 22:29 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 22:29 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 22:29 .
drwxr-xr-x 4 user user  4096 Jun 30 22:29 ..
-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 22:29 .
drwxr-xr-x 4 user user    4096 Jun 30 22:29 ..
-rw-r--r-- 1 user user 2967336 Jun 30 11:01 train.npz
shell
wc -l submission/*.py run_checks.py test.sh 2>/dev/null
output
98 submission/advtrain.py
   162 submission/attack.py
   473 submission/autograd.py
    51 submission/data.py
   378 submission/nn.py
   219 submission/optim.py
    79 submission/train.py
  1187 run_checks.py
    19 test.sh
  2666 total
I'll read all the stub files first to understand the structure and contracts.

/app/submission/autograd.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]

/app/submission/nn.py

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]

/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]
Now let me read the run_checks.py to understand exact expectations.

/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 let me check the data shape and test.sh.
shell
python3 -c "
import numpy as np
d = np.load('data/train.npz')
print(list(d.keys()))
X, y = d['X'], d['y']
print('X', X.shape, X.dtype, X.min(), X.max())
print('y', y.shape, y.dtype, np.unique(y), np.bincount(y))
" && echo "---TEST.SH---" && cat test.sh
output
['X', 'y']
X (3600, 1, 16, 16) float32 0.0 1.0
y (3600,) int64 [0 1 2 3 4 5] [593 592 629 596 599 591]
---TEST.SH---
#!/usr/bin/env bash
# Smoke test (NOT the grader): confirms the environment is wired -- numpy imports, the training
# split loads, and the submission stubs are present. It does NOT check correctness (the stubs raise
# NotImplementedError until you implement them).
set -uo pipefail

python3 - <<'PY'
import numpy as np, os
p = "/app/data/train.npz"
assert os.path.exists(p), "missing train.npz"
d = np.load(p)
print(f"train.npz: X{d['X'].shape} {d['X'].dtype}  y{d['y'].shape}  classes={len(set(d['y'].tolist()))}")
for f in ("autograd.py", "nn.py", "optim.py", "data.py", "attack.py", "advtrain.py", "train.py"):
    assert os.path.exists(f"/app/submission/{f}"), f"missing /app/submission/{f}"
assert os.path.exists("/app/run_checks.py"), "missing /app/run_checks.py (public component runner)"
print("submission stubs present:", sorted(os.listdir("/app/submission")))
print("numpy", np.__version__)
PY
echo "app_test smoke OK (run 'python3 /app/run_checks.py' for the per-check progress report)"
Now I have a complete understanding. The data is 6 classes, 16×16, 1 channel. Let me create the task list and start implementing `autograd.py`.
shell
python3 -c "import numpy; print(numpy.__version__)"
output
2.2.6
Let me write `autograd.py` in full. I'll build it in pieces to stay under the size limit.
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


def _restore_dims(g, shape, axis, keepdims) -> np.ndarray:
    """Broadcast a reduced gradient/array g back to full `shape`."""
    g = np.asarray(g, dtype=np.float64)
    if axis is None:
        return np.broadcast_to(g, shape).astype(np.float64)
    if not keepdims:
        ax = axis if isinstance(axis, tuple) else (axis,)
        ax = tuple(a % len(shape) for a in ax)
        g = np.expand_dims(g, ax)
    return np.broadcast_to(g, shape).astype(np.float64)


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

    def __init__(self, data, requires_grad: bool = False, _parents: Iterable["Tensor"] = ()):  # noqa: D401
        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._
…[truncated 2534 chars]

contents
The file /app/submission/autograd.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now I'll append the operations. Let me add the binary, unary, and reduction ops.
shell
cat >> /app/submission/autograd.py <<'PYEOF'


# ===================================================================== element-wise binary
def add(a, b) -> Tensor:
    a = _ensure(a); b = _ensure(b)
    rg = a.requires_grad or b.requires_grad
    out = Tensor(a.data + b.data, requires_grad=rg, _parents=(a, b))

    def _backward():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g, b.data.shape))
    out._backward = _backward
    return out


def sub(a, b) -> Tensor:
    a = _ensure(a); b = _ensure(b)
    rg = a.requires_grad or b.requires_grad
    out = Tensor(a.data - b.data, requires_grad=rg, _parents=(a, b))

    def _backward():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(-g, b.data.shape))
    out._backward = _backward
    return out


def mul(a, b) -> Tensor:
    a = _ensure(a); b = _ensure(b)
    rg = a.requires_grad or b.requires_grad
    out = Tensor(a.data * b.data, requires_grad=rg, _parents=(a, b))

    def _backward():
        g = out.grad
        if a.requires_grad:
            a._accum(_unbroadcast(g * b.data, a.data.shape))
        if b.requires_grad:
            b._accum(_unbroadcast(g * a.data, b.data.shape))
    out._backward = _backward
    return out


def div(a, b) -> Tensor:
    a = _ensure(a); b = _ensure(b)
    rg = a.re
…[truncated 3240 chars]
output
appended binary/unary
shell
cat >> /app/submission/autograd.py <<'PYEOF'


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

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


def mean(a, axis=None, keepdims=False) -> Tensor:
    a = _ensure(a)
    out = Tensor(a.data.mean(axis=axis, keepdims=keepdims),
                 requires_grad=a.requires_grad, _parents=(a,))
    n = a.data.size / max(1, out.data.size)

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


def _reduce_extreme(a, axis, keepdims, is_max):
    a = _ensure(a)
    val = a.data.max(axis=axis, keepdims=keepdims) if is_max else a.data.min(axis=axis, keepdims=keepdims)
    out = Tensor(val, requires_grad=a.requires_grad, _parents=(a,))

    def _backward():
        if a.requires_grad:
            full = _restore_dims(out.data, a.data.shape, axis, keepdims)
            g = _restore_dims(out.grad, a.data.shape, axis, keepdims)
            mask = (a.data == full).astype(np.float64)
            denom = mask.sum(axis=axis, keepdims=True)
            a._accum(g * mask / denom)

…[truncated 5684 chars]
output
appended reductions
shell
cat >> /app/submission/autograd.py <<'PYEOF'


# ===================================================================== nonlinearities
def relu(a) -> Tensor:
    a = _ensure(a)
    return _unary(a, np.maximum(a.data, 0.0), lambda: (a.data > 0).astype(np.float64))


def leaky_relu(a, slope: float = 0.01) -> Tensor:
    a = _ensure(a)
    return _unary(a, np.where(a.data > 0, a.data, slope * a.data),
                  lambda: np.where(a.data > 0, 1.0, slope))


def sigmoid(a) -> Tensor:
    a = _ensure(a); s = 1.0 / (1.0 + np.exp(-a.data))
    return _unary(a, s, lambda: s * (1.0 - s))


def tanh(a) -> Tensor:
    a = _ensure(a); t = np.tanh(a.data)
    return _unary(a, t, lambda: 1.0 - t * t)


def gelu(a) -> Tensor:
    a = _ensure(a); x = a.data
    cdf = 0.5 * (1.0 + _erf(x / np.sqrt(2.0)))
    val = x * cdf
    pdf = np.exp(-0.5 * x * x) / np.sqrt(2.0 * np.pi)
    return _unary(a, val, lambda: cdf + x * pdf)


def softplus(a, beta: float = 1.0) -> Tensor:
    a = _ensure(a); x = a.data
    val = np.logaddexp(0.0, beta * x) / beta
    return _unary(a, val, lambda: 1.0 / (1.0 + np.exp(-beta * x)))


def silu(a) -> Tensor:
    a = _ensure(a); x = a.data; s = 1.0 / (1.0 + np.exp(-x))
    return _unary(a, x * s, lambda: s + x * s * (1.0 - s))


def mish(a) -> Tensor:
    a = _ensure(a); x = a.data
    sp = np.logaddexp(0.0, x)
    tsp = np.tanh(sp)
    s = 1.0 / (1.0 + np.exp(-x))
    return _unary(a, x * tsp, lambda: tsp + x * s * (1.0 - tsp * tsp))


def elu(a, alpha: float = 
…[truncated 4477 chars]
output
appended nonlin/losses
shell
cat >> /app/submission/autograd.py <<'PYEOF'


# ===================================================================== normalization
def layernorm(a, gamma, beta, eps: float = 1e-5) -> Tensor:
    a = _ensure(a); gamma = _ensure(gamma); beta = _ensure(beta)
    x = a.data
    mu = x.mean(axis=-1, keepdims=True)
    var = x.var(axis=-1, keepdims=True)
    istd = 1.0 / np.sqrt(var + eps)
    xhat = (x - mu) * istd
    out = Tensor(gamma.data * xhat + beta.data,
                 requires_grad=(a.requires_grad or gamma.requires_grad or beta.requires_grad),
                 _parents=(a, gamma, beta))
    D = x.shape[-1]

    def _backward():
        g = out.grad
        if gamma.requires_grad:
            gamma._accum(_unbroadcast(g * xhat, gamma.data.shape))
        if beta.requires_grad:
            beta._accum(_unbroadcast(g, beta.data.shape))
        if a.requires_grad:
            dxhat = g * gamma.data
            dx = istd * (dxhat - dxhat.mean(axis=-1, keepdims=True)
                         - xhat * (dxhat * xhat).mean(axis=-1, keepdims=True))
            a._accum(dx)
    out._backward = _backward
    return out


def batchnorm(a, gamma, beta, eps: float = 1e-5) -> Tensor:
    a = _ensure(a); gamma = _ensure(gamma); beta = _ensure(beta)
    x = a.data
    mu = x.mean(axis=0, keepdims=True)
    var = x.var(axis=0, keepdims=True)
    istd = 1.0 / np.sqrt(var + eps)
    xhat = (x - mu) * istd
    out = Tensor(gamma.data * xhat + beta.data,
                 requires_grad=(a.r
…[truncated 7491 chars]
output
appended norm/conv/pool
`autograd.py` is complete. Let me quickly sanity-check it imports and basic grads work.
shell
cd /app/submission && python3 -c "
import numpy as np, autograd as ag
T=ag.Tensor
# conv input grad fd check
rng=np.random.default_rng(0)
x=rng.standard_normal((2,2,6,6)); W=rng.standard_normal((3,2,3,3)); b=rng.standard_normal(3)
xt=T(x.copy(),requires_grad=True)
ag.sum(ag.conv2d(xt,T(W),T(b),pad=1)).backward()
def fd(xv):
    e=1e-5; g=np.zeros_like(xv); f=xv.reshape(-1); gf=g.reshape(-1)
    for i in range(f.size):
        o=f[i]; f[i]=o+e; fp=ag.conv2d(T(xv),T(W),T(b),pad=1).data.sum(); f[i]=o-e; fm=ag.conv2d(T(xv),T(W),T(b),pad=1).data.sum(); f[i]=o; gf[i]=(fp-fm)/(2*e)
    return g
gn=fd(x.copy())
print('conv x err', np.abs(xt.grad-gn).max())
# layernorm
x=rng.standard_normal((4,6)); ga=T(rng.standard_normal(6)); be=T(rng.standard_normal(6))
lt=T(x.copy(),requires_grad=True); ag.sum(ag.layernorm(lt,ga,be)).backward()
def fdl(xv):
    e=1e-5; g=np.zeros_like(xv); f=xv.reshape(-1); gf=g.reshape(-1)
    for i in range(f.size):
        o=f[i]; f[i]=o+e; fp=ag.layernorm(T(xv),ga,be).data.sum(); f[i]=o-e; fm=ag.layernorm(T(xv),ga,be).data.sum(); f[i]=o; gf[i]=(fp-fm)/(2*e)
    return g
print('ln x err', np.abs(lt.grad-fdl(x.copy())).max())
print('OK')
"
output
conv x err 2.547817068432323e-09
ln x err 1.445130681787532e-10
OK
Excellent. Now let me implement `nn.py`. Let me fill in all the forwards.
shell
python3 - <<'PY'
import re
f='nn.py'
s=open(f).read()
repl = [
("""    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 1738 chars]
output
done part1
shell
python3 - <<'PY'
f='nn.py'
s=open(f).read()
repl=[
("""    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 = gi[:, 0:H]; i_z = gi[:, H:2 * H]; i_n = gi[:, 2 * H:3 * H]
        h_r = gh[:, 0:H]; h_z = gh[:, H:2 * H]; h_n = 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 = Tensor(np.ones_like(z.data))
        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').\"\"\"
…[truncated 1736 chars]
output
done part2
Now `data.py`:
write · /app/submission/data.py
"""Data loading + minibatching for the shape-classification set."""
from __future__ import annotations

from typing import Iterator, Tuple

import numpy as np


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)
    n_val = int(round(val_frac * n))
    val_idx = perm[:n_val]
    tr_idx = perm[n_val:]
    return (X[tr_idx], y[tr_idx]), (X[val_idx], y[val_idx])


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]:
    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:
    y = np.asarray(y, dtype=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:
    retu
…[truncated 24 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 fill in all the step methods and helpers.
shell
python3 - <<'PY'
f='optim.py'
s=open(f).read()
repl=[
('''    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
            step = (g + self.momentum * self._v[i]) if self.nesterov else self._v[i]
            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 is None:
                c
…[truncated 4953 chars]
output
done optim
Now let me run the checks for the milestones implemented so far (autograd, nn, optim, data).
shell
cd /app && python3 run_checks.py --only autograd_grads 2>&1 | tail -20
output
grad/nn.Linear_x                         OK  
  grad/nn.LayerNorm_x                      OK  
  grad/nn.BatchNorm1d_x                    OK  
  grad/cnn_grad_fc2.bias                   OK    (max_abs=1.71e-11)
  grad/cnn_grad_conv1.weight               OK    (max_abs=2.36e-11)
  grad/cnn_grad_conv2.weight               OK    (max_abs=2.75e-11)
  grad/cnn_grad_fc1.weight                 OK    (max_abs=3.44e-11)
  grad/cnn_input_grad                      OK    (max_abs=1.86e-11)
  grad/nn.GroupNorm_x                      OK  
  grad/nn.RMSNorm_x                        OK  
  grad/rnncell                             OK    (max_abs=1.03e-10)
  grad/grucell                             OK    (max_abs=1.84e-10)
  grad/lstmcell                            OK    (max_abs=4.13e-11)
  grad/rescnn_param                        OK    (max_abs=2.00e-11)
  grad/rescnn_input                        OK    (max_abs=2.21e-11)

------------------------------------------------------------------------
autograd_grads 77/82
TOTAL  77/82 public checks passing
Fix the FAIL lines above, then re-run. Each names a backward/forward/optimizer/attack/adversarial-training bug.
shell
python3 run_checks.py --only autograd_grads 2>&1 | grep FAIL
output
grad/mean_all                            FAIL  (raised AxisError: axis 1 is out of bounds for array of dimension 0)
  grad/mean_axis                           FAIL  (raised AxisError: axis 4 is out of bounds for array of dimension 0)
  grad/var_axis                            FAIL  (raised AxisError: axis 4 is out of bounds for array of dimension 0)
  grad/var_keep                            FAIL  (raised AxisError: axis 4 is out of bounds for array of dimension 0)
  grad/std_axis                            FAIL  (raised AxisError: axis 4 is out of bounds for array of dimension 0)
Fix the FAIL lines above, then re-run. Each names a backward/forward/optimizer/attack/adversarial-training bug.
shell
cd /app/submission && python3 -c "
import numpy as np, autograd as ag, traceback
T=ag.Tensor
try:
    t=T(np.random.randn(4,5),requires_grad=True)
    ag.sum(ag.mean(t)).backward()
    print('mean_all grad ok', t.grad.shape)
except Exception as e:
    traceback.print_exc()
"
output
Traceback (most recent call last):
  File "<string>", line 6, in <module>
  File "/app/submission/autograd.py", line 329, in mean
    n = a.data.size / max(1, out.data.size)
                      ^^^^^^^^^^^^^^^^^^^^^
  File "/app/submission/autograd.py", line 355, in max
    return _reduce_extreme(a, axis, keepdims, True)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/submission/autograd.py", line 340, in _reduce_extreme
    val = a.data.max(axis=axis, keepdims=keepdims) if is_max else a.data.min(axis=axis, keepdims=keepdims)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/numpy/_core/_methods.py", line 44, in _amax
    return umr_maximum(a, axis, None, out, keepdims, initial, where)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
numpy.exceptions.AxisError: axis 1 is out of bounds for array of dimension 0
The module-level `max` shadows builtin. Let me fix those computations.
shell
python3 - <<'PY'
f='autograd.py'
s=open(f).read()
s=s.replace("    n = a.data.size / max(1, out.data.size)",
            "    n = a.data.size / out.data.size")
s=s.replace("    n = a.data.size / max(1, (a.data.sum(axis=axis, keepdims=True)).size)\n    den = (n - 1) if unbiased else n\n    val = (diff ** 2).sum(axis=axis, keepdims=keepdims) / den",
            "    n = a.data.size / (a.data.sum(axis=axis, keepdims=True)).size\n    den = (n - 1) if unbiased else n\n    val = (diff ** 2).sum(axis=axis, keepdims=keepdims) / den")
s=s.replace("    n = a.data.size / max(1, (a.data.sum(axis=axis, keepdims=True)).size)\n    den = (n - 1) if unbiased else n\n    v = (diff ** 2).sum(axis=axis, keepdims=True) / den + eps",
            "    n = a.data.size / (a.data.sum(axis=axis, keepdims=True)).size\n    den = (n - 1) if unbiased else n\n    v = (diff ** 2).sum(axis=axis, keepdims=True) / den + eps")
open(f,'w').write(s)
print("fixed")
PY
cd /app && python3 run_checks.py --only autograd_grads 2>&1 | tail -3
output
fixed
autograd_grads 82/82
TOTAL  82/82 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.
shell
python3 run_checks.py --only nn_forward 2>&1 | tail -3 && python3 run_checks.py --only optim 2>&1 | tail -3 && python3 run_checks.py --only data 2>&1 | tail -3
output
nn_forward 22/22
TOTAL  22/22 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.
optim 20/20
TOTAL  20/20 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.
data 3/3
TOTAL  3/3 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 `attack.py`. Let me implement the attack zoo.
shell
python3 - <<'PY'
f='attack.py'
s=open(f).read()
repl=[
('''    raise NotImplementedError("implement loss_input_grad")''',
'''    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)'''),
('''    raise NotImplementedError("implement input_grad")''',
'''    return loss_input_grad(model, x, y, lambda lg, t: ag.cross_entropy(lg, t))'''),
('''    raise NotImplementedError("implement cw_margin_loss")''',
'''    logits = logits if isinstance(logits, Tensor) else Tensor(logits)
    y = np.asarray(y)
    N, C = logits.data.shape
    onehot = np.zeros((N, C)); onehot[np.arange(N), y] = 1.0
    z_y = ag.sum(ag.mul(logits, Tensor(onehot)), axis=1)
    other = ag.add(logits, Tensor(onehot * (-1e9)))
    z_other = ag.max(other, axis=1)
    margin = ag.sub(z_y, z_other)
    return ag.mean(ag.maximum(ag.mul(margin, -1.0), Tensor(np.full(N, -kappa))))'''),
('''    raise NotImplementedError("implement dlr_loss")''',
'''    logits = logits if isinstance(logits, Tensor) else Tensor(logits)
    y = np.asarray(y)
    N, C = logits.data.shape
    onehot = np.zeros((N, C)); onehot[np.arange(N), y] = 1.0
    z_y = ag.sum(ag.mul(logits, Tensor(onehot)), axis=1)
    other = ag.add(logits, Tensor(onehot * (-1e9)))
    z_other = ag.max(other, axis=1)
    z_max = ag.max(logits, axis=1)
    z_mean = ag.mean(logits, axis=1)
    num = ag.sub(z_y, z_other)
    den = ag.add(ag.s
…[truncated 889 chars]
output
Exit code 1
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
FileNotFoundError: [Errno 2] No such file or directory: 'attack.py'
shell
cd /app/submission && python3 - <<'PY'
f='attack.py'
s=open(f).read()
repl=[
('''    raise NotImplementedError("implement loss_input_grad")''',
'''    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)'''),
('''    raise NotImplementedError("implement input_grad")''',
'''    return loss_input_grad(model, x, y, lambda lg, t: ag.cross_entropy(lg, t))'''),
('''    raise NotImplementedError("implement cw_margin_loss")''',
'''    logits = logits if isinstance(logits, Tensor) else Tensor(logits)
    y = np.asarray(y)
    N, C = logits.data.shape
    onehot = np.zeros((N, C)); onehot[np.arange(N), y] = 1.0
    z_y = ag.sum(ag.mul(logits, Tensor(onehot)), axis=1)
    other = ag.add(logits, Tensor(onehot * (-1e9)))
    z_other = ag.max(other, axis=1)
    margin = ag.sub(z_y, z_other)
    return ag.mean(ag.maximum(ag.mul(margin, -1.0), Tensor(np.full(N, -kappa))))'''),
('''    raise NotImplementedError("implement dlr_loss")''',
'''    logits = logits if isinstance(logits, Tensor) else Tensor(logits)
    y = np.asarray(y)
    N, C = logits.data.shape
    onehot = np.zeros((N, C)); onehot[np.arange(N), y] = 1.0
    z_y = ag.sum(ag.mul(logits, Tensor(onehot)), axis=1)
    other = ag.add(logits, Tensor(onehot * (-1e9)))
    z_other = ag.max(other, axis=1)
    z_max = ag.max(logits, axis=1)
    z_mean = ag.mean(logits, axis=1)
    num = ag.sub(z_y, z_other)
…[truncated 911 chars]
output
done attack part1
shell
python3 - <<'PY'
f='attack.py'
s=open(f).read()
repl=[
('''    raise NotImplementedError("implement pgd_attack")''',
'''    lo, hi = clip
    x = np.asarray(x, dtype=np.float64)
    if x0 is not None:
        x_adv = np.asarray(x0, dtype=np.float64).copy()
    elif rng is not None:
        x_adv = x + rng.uniform(-eps, eps, size=x.shape)
    else:
        x_adv = x + np.random.default_rng().uniform(-eps, eps, size=x.shape)
    x_adv = project_linf(x_adv, x, eps, lo, hi)
    for _ in range(steps):
        g = input_grad(model, x_adv, y)
        x_adv = x_adv + alpha * np.sign(g)
        x_adv = project_linf(x_adv, x, eps, lo, hi)
    return x_adv'''),
('''    raise NotImplementedError("implement mi_fgsm")''',
'''    lo, hi = clip
    x = np.asarray(x, dtype=np.float64)
    if rng is not None:
        x_adv = project_linf(x + rng.uniform(-eps, eps, size=x.shape), x, eps, lo, hi)
    else:
        x_adv = x.copy()
    g_mom = np.zeros_like(x)
    for _ in range(steps):
        g = input_grad(model, x_adv, y)
        l1 = np.sum(np.abs(g).reshape(x.shape[0], -1), axis=1).reshape(-1, *([1] * (x.ndim - 1)))
        g_mom = mu * g_mom + g / (l1 + 1e-12)
        x_adv = x_adv + alpha * np.sign(g_mom)
        x_adv = project_linf(x_adv, x, eps, lo, hi)
    return x_adv'''),
('''    raise NotImplementedError("implement targeted_pgd")''',
'''    lo, hi = clip
    x = np.asarray(x, dtype=np.float64)
    if rng is not None:
        x_adv = project_linf(x + rng.uniform(-eps, eps, size=x.sh
…[truncated 4183 chars]
output
done attack part2
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`. Let me write all ten losses.
shell
cd /app/submission && python3 - <<'PY'
f='advtrain.py'
s=open(f).read()
repl=[
('''    raise NotImplementedError("implement pgd_at_loss")''',
'''    return ag.cross_entropy(model(Tensor(x_adv)), y)'''),
('''    raise NotImplementedError("implement trades_loss")''',
'''    cl = model(Tensor(x_clean)); ad = model(Tensor(x_adv))
    ce = ag.cross_entropy(cl, y)
    tgt = Tensor(cl.data.copy())
    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)}'''),
('''    raise NotImplementedError("implement mart_loss")''',
'''    y = np.asarray(y)
    ad = model(Tensor(x_adv)); cl = model(Tensor(x_clean))
    N, C = ad.data.shape
    onehot = np.zeros((N, C)); onehot[np.arange(N), y] = 1.0
    ce_adv = ag.cross_entropy(ad, y)
    padv = ag.softmax(ad)
    p_other = ag.max(ag.add(padv, Tensor(onehot * (-1e9))), axis=1)
    one = Tensor(np.ones(N))
    term2 = ag.mul(ag.mean(ag.log(ag.sub(one, p_other))), -1.0)
    boosted = ag.add(ce_adv, term2)
    pclean = ag.softmax(cl)
    logpclean_det = Tensor(np.log(pclean.data + 1e-12))
    logpadv = ag.log_softmax(ad)
    kl_per = ag.sum(ag.mul(padv, ag.sub(logpadv, logpclean_det)), axis=1)
    weight = Tensor(1.0 - pclean.data[np.arange(N), y])
    kl_term = ag.mean(ag.mul(weight, kl_per))
    loss = ag.add(boosted, ag.mul(kl_term, float(beta)))
    return loss, {"ce": float(ce_adv.data), "kl": float(kl_term.data), "loss": float(loss.data)}'
…[truncated 2744 chars]
output
done advtrain
python3: can't open file '/app/submission/run_checks.py': [Errno 2] No such file or directory
shell
cd /app && python3 run_checks.py --only advtrain 2>&1 | tail -20
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=4.29e-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=2.35e-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.
All advtrain pass. Now let me run the full suite.
shell
python3 run_checks.py 2>&1 | tail -8
output
data/get_batch_shape                     OK    ((16, 1, 8, 8),(16,))
  data/train_val_split                     OK    (30/10)
  data/to_onehot                           OK  

------------------------------------------------------------------------
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.
All 163 public checks pass. Now Part B: implement `train.py` and adversarially train the model. Let me write the training loop.

/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, restarts, rng, limit=400):
    n = min(limit, X.shape[0])
    Xs, ys = X[:n], y[:n]
    clean_pred = model(Xs).data.argmax(1)
    correct = clean_pred == ys
    xadv = A.pgd_restarts(model, Xs, ys, eps, steps, alpha, restarts=restarts, rng=rng)
    adv_pred = model(xadv).data.argmax(1)
    robust = correct & (adv_pred == ys)
    return float(robust.mean()), float(correct.mean())


def train(train_path, out_path, epochs=20, 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=10, 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."""
    import math as _m
    X, y = D.load_npz(train_path)
    n_classes = int(y.max()) + 1
    c_in = X.shape[1]
    img = 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)
    params = model.params()
    opt = O.AdamW(params, lr=lr, betas=(0.9, 0.999), weight_decay=weight_decay, no_decay_ndim=1)

    steps_per_epoch = int(_m.ceil(len(Xtr) / batch_size))
    total_steps = epochs * steps_per_epoch
    warmup = steps_per_epoch  # one epoch warmup
    step_count = 0
    best_robust = -1.0
    best_state = None

    for epoch in range(epoc
…[truncated 1292 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 1-epoch run to gauge speed.
shell
cd /app/submission && time python3 -c "
import train
train.train('/app/data/train.npz','/tmp/test_model.npz', epochs=1, seed=0)
" 2>&1 | tail -5
output
real	0m1.582s
user	0m0.876s
sys	0m0.691s
shell
python3 -c "
import train
train.train('/app/data/train.npz','/tmp/test_model.npz', epochs=2, seed=0)
" 2>&1 | tail -10
output
(Bash completed with no output)
shell
python3 -u -c "
import sys
import train
print('imported', flush=True)
s=train.train('/app/data/train.npz','/tmp/test_model.npz', epochs=2, seed=0)
print('returned', flush=True)
"
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 = 0.5825  < 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_0c842e5bef2e47ed. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_0c842e5bef2e47ed · verifier authoritative; classifier explanatory.