SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

qat-int2-cifar

claude-code claude-sonnet-4-6 ✗ 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.
SubtypeImplementation Bugs
EvidenceTest output shows: 'COMPONENT CONFORMANCE SUITE: 276/278 cases passed (all milestones pass: False)' with 'failing milestones: integration (21/23)'. The held-out metric achieved 0.8947, exceeding the 0.7 threshold. Only 2 component test failures out of 278, but the integration milestone (full-model QAT training steps) failed, blocking reward despite strong partial performance. The agent's train.py and framework implementation were correct enough to achieve the final metric threshold but failed on the integration trajectory matching requirement.
Root causeThe agent implemented 99.3% of the complex numpy-based deep learning framework correctly (276/278 gradient/forward/optimizer checks pass), and the trained model generalized well (held-out top-1 = 0.8947 > 0.7 threshold). However, the framework has a subtle correctness issue in how operations compose during end-to-end training (the integration milestone), causing 2 of 23 training trajectory tests to fail. This indicates the agent got very close but missed a subtle implementation detail in framework semantics that only manifests in full training loops.
RecommendationN/A - task is fine. This is a hard, multi-part task requiring correct implementation of complex deep learning machinery. The agent achieved 99.3% on isolated component tests and exceeded the final metric threshold, demonstrating strong understanding. The integration milestone failures suggest subtle bugs in how the framework's operations interact during training (e.g., state accumulation, update ordering, or numerical stability), which are reasonable gotchas for an agent to miss on such a complex implementation task.
Trajectory
Tool-by-tool agent trajectory
34 tool calls · 4 tool types · 46 steps
Agent session started, model: claude-sonnet-4-6 · 29 tools available · cwd: /app
I'll start by exploring the repository structure to understand what's provided and what needs to be implemented.

Explore repository structure

shell
find /app -type f | head -50 && echo "---" && ls /app/submission/
output
/app/run_checks.py
/app/test.sh
/app/timer.sh
/app/PROMPT.txt
/app/agent.pid
/app/run.log
/app/agent_trajectory.jsonl
/app/agent.stderr
/app/submission/nn.py
/app/submission/autograd.py
/app/submission/train.py
/app/submission/optim.py
/app/submission/data.py
/app/data/train.npz
---
autograd.py
data.py
nn.py
optim.py
train.py

Run initial checks to see current state

shell
python3 /app/run_checks.py --quiet 2>&1 | head -50
output
------------------------------------------------------------------------
autograd_grads 0/115 | quant_grads 3/21 | nn_forward 42/53 | optim 1/25 | integration 0/6 | data 0/2
TOTAL  46/222 public checks passing
Fix the FAIL lines above (each is a backward/forward/optimizer bug). Re-run until all green, then train.

/app/submission/autograd.py

contents
1	"""Reverse-mode automatic differentiation over numpy arrays.
2	
3	YOU MUST IMPLEMENT EVERYTHING MARKED ``# TODO`` / ``raise NotImplementedError`` using numpy
4	ONLY. No torch/jax/tensorflow/autograd/etc. The grader's conformance suite (a) differentiates the
5	differentiable ops below with central finite differences and compares against YOUR analytic
6	backward, and (b) checks the LSQ ``fake_quant`` STE + scale gradient against the reference
7	definition, so every backward must be correct (a single wrong reduction / STE / Jacobian fails
8	the gradient checks and zeroes the reward).
9	
10	A ``Tensor`` wraps one ``numpy.ndarray`` (stored as ``float64`` in ``self.data``) and records the
11	op that produced it so ``.backward()`` can accumulate ``.grad`` into every leaf.
12	
13	CONTRACT (the grader builds its own reference against this exact API):
14	* ``Tensor(data, requires_grad=False)`` -- ``self.data`` is ``float64``; ``self.grad`` is None
15	  until backward, then a same-shape ``float64`` array. requires_grad leaves accumulate grad.
16	* Every op returns a NEW Tensor whose ``requires_grad`` is the OR of its differentiable inputs,
17	  and whose ``_backward`` closure does ``input._accum(local_grad)`` (so multiple paths add up).
18	* ``t.backward(grad=None)`` -- seeds ``grad`` (all-ones for a scalar) and walks the graph in
19	  reverse topological order, calling each node's ``_backward``. Repeated backward accumulates.
20	* BROADCASTING: binary ops broadcast like numpy; the ba
…[truncated 3132 chars]

/app/submission/nn.py

contents
1	"""QAT layers + a small INT2 CNN, built on YOUR autograd engine.
2	
3	Implement every ``# TODO`` forward (the parameters + ``named_params``/``buffers`` naming are
4	already wired for you; you compose the autograd ops). The grader checks each layer's forward
5	against its OWN reference AND finite-difference-checks the gradients that flow through your
6	autograd, so the composition must be exactly right.
7	
8	CHECKPOINT NAMING CONTRACT (the grader loads YOUR ``qat_model.npz`` into its own reference
9	QuantCNN by these exact keys/shapes -- do not rename):
10	  stem.conv.weight (W0,3,3,3) | stem.conv.wq.scale (1,) | stem.bn.gamma/.beta (W0,) | stem.aq.scale (1,)
11	  blocks.{i}.conv.weight (Cout,Cin,3,3) | blocks.{i}.conv.wq.scale (1,)
12	  blocks.{i}.bn.gamma/.beta (Cout,) | blocks.{i}.aq.scale (1,)
13	  head.weight (Cfeat,n_classes) | head.wq.scale (1,) | head.bias (n_classes,)
14	BN running stats are BUFFERS (saved alongside params, NOT trained by the optimizer, NOT audited):
15	  stem.bn.running_mean/.running_var (W0,) | blocks.{i}.bn.running_mean/.running_var (Cout,)
16	
17	Quantization: every conv/head WEIGHT is LSQ-quantized to a signed 2-bit grid {-2,-1,0,1} via a
18	per-tensor learnable step before use; every block activation (post-relu) is LSQ-quantized to an
19	unsigned 2-bit grid {0,1,2,3}. Conv = 3x3 same-padding cross-correlation. Linear head = x@weight+bias.
20	"""
21	from __future__ import annotations
22	
23	from typing import Dict, List
24	
25	import numpy as n
…[truncated 2470 chars]
Let me read all the stub files completely to understand the full scope.

/app/submission/autograd.py

contents
100	
101	    def __repr__(self):
102	        return f"Tensor(shape={self.data.shape}, requires_grad={self.requires_grad})"
103	
104	
105	def _ensure(x) -> Tensor:
106	    return x if isinstance(x, Tensor) else Tensor(x)
107	
108	
109	def _mk(data, parents, requires_grad) -> Tensor:
110	    return Tensor(data, requires_grad=requires_grad, _parents=parents)
111	
112	
113	# ============================================================ element-wise binary (broadcasting)
114	def add(a, b) -> Tensor:
115	    """out = a + b (numpy broadcasting). Backward: each input gets _unbroadcast(out.grad)."""
116	    a, b = _ensure(a), _ensure(b)
117	    out = _mk(a.data + b.data, (a, b), a.requires_grad or b.requires_grad)
118	
119	    def _bw():
120	        raise NotImplementedError("add backward")  # TODO
121	
122	    out._backward = _bw
123	    return out
124	
125	
126	def sub(a, b) -> Tensor:
127	    """out = a - b. Backward: a gets +grad, b gets -grad (both _unbroadcast)."""
128	    a, b = _ensure(a), _ensure(b)
129	    out = _mk(a.data - b.data, (a, b), a.requires_grad or b.requires_grad)
130	
131	    def _bw():
132	        raise NotImplementedError("sub backward")  # TODO
133	
134	    out._backward = _bw
135	    return out
136	
137	
138	def mul(a, b) -> Tensor:
139	    """out = a * b (elementwise). Backward: a gets grad*b, b gets grad*a (both _unbroadcast)."""
140	    a, b = _ensure(a), _ensure(b)
141	    out = _mk(a.data * b.data, (a, b), a.requires_grad or b.requires_grad)
142	
143	   
…[truncated 8507 chars]

/app/submission/nn.py

contents
100	    def __init__(self, d, eps=1e-5):
101	        self.gamma = Tensor(np.ones(d), requires_grad=True)
102	        self.beta = Tensor(np.zeros(d), requires_grad=True)
103	        self.eps = eps
104	
105	    def forward(self, x: Tensor) -> Tensor:
106	        # TODO: return ag.layernorm(x, self.gamma, self.beta, self.eps)
107	        raise NotImplementedError("LayerNorm.forward")
108	
109	    def named_params(self):
110	        return {"gamma": self.gamma, "beta": self.beta}
111	
112	
113	class Conv2d(Module):
114	    """Full-precision (un-quantized) 2-D conv layer with bias, used by the generic-layer checks."""
115	
116	    def __init__(self, Cin, Cout, k, rng, stride=1, padding=1, bias=True):
117	        std = np.sqrt(2.0 / (Cin * k * k))
118	        self.weight = Tensor(rng.standard_normal((Cout, Cin, k, k)) * std, requires_grad=True)
119	        self.bias = Tensor(np.zeros(Cout), requires_grad=True) if bias else None
120	        self.stride = stride
121	        self.padding = padding
122	
123	    def forward(self, x: Tensor) -> Tensor:
124	        # TODO: return ag.conv2d(x, self.weight, bias=self.bias, stride=self.stride, pad=self.padding)
125	        raise NotImplementedError("Conv2d.forward")
126	
127	    def named_params(self):
128	        d = {"weight": self.weight}
129	        if self.bias is not None:
130	            d["bias"] = self.bias
131	        return d
132	
133	
134	class MaxPool2d(Module):
135	    def __init__(self, k):
136	        self.k = k
137	
138	    
…[truncated 6103 chars]
This is a massive implementation task. Let me read the rest of the files to understand the complete scope.

/app/submission/autograd.py

contents
400	    out._backward = _bw
401	    return out
402	
403	
404	# ============================================================ nonlinearities
405	def relu(a) -> Tensor:
406	    """max(a, 0). Backward: grad * (a > 0)."""
407	    a = _ensure(a)
408	    out = _mk(np.maximum(a.data, 0.0), (a,), a.requires_grad)
409	
410	    def _bw():
411	        raise NotImplementedError("relu backward")  # TODO
412	
413	    out._backward = _bw
414	    return out
415	
416	
417	def leaky_relu(a, slope: float = 0.01) -> Tensor:
418	    """out = a where a>0 else slope*a. Backward: grad where a>0, slope*grad where a<=0."""
419	    a = _ensure(a)
420	    out = _mk(np.where(a.data > 0.0, a.data, slope * a.data), (a,), a.requires_grad)
421	
422	    def _bw():
423	        raise NotImplementedError("leaky_relu backward")  # TODO
424	
425	    out._backward = _bw
426	    return out
427	
428	
429	def sigmoid(a) -> Tensor:
430	    """out = 1/(1+exp(-a)). Backward: grad * out * (1 - out)."""
431	    a = _ensure(a)
432	    with np.errstate(over="ignore"):
433	        s = 1.0 / (1.0 + np.exp(-a.data))
434	    out = _mk(s, (a,), a.requires_grad)
435	
436	    def _bw():
437	        raise NotImplementedError("sigmoid backward")  # TODO
438	
439	    out._backward = _bw
440	    return out
441	
442	
443	def tanh(a) -> Tensor:
444	    """out = tanh(a). Backward: grad * (1 - tanh(a)**2)."""
445	    a = _ensure(a)
446	    out = _mk(np.tanh(a.data), (a,), a.requires_grad)
447	
448	    def _bw():
449	        raise NotImpleme
…[truncated 14847 chars]

/app/submission/nn.py

contents
300	        for w in widths[1:]:
301	            layout.append((w, 2))
302	            layout.append((w, 1))
303	        for (w, st) in layout:
304	            blocks.append(ConvBlock(cin, w, rng, stride=st))
305	            cin = w
306	        self.blocks = blocks
307	        self.feat = cin
308	        std = 1.0 / np.sqrt(self.feat)
309	        self.head_w = Tensor(rng.standard_normal((self.feat, n_classes)) * std, requires_grad=True)
310	        self.head_wq = WeightQuant()
311	        self.head_b = Tensor(np.zeros(n_classes), requires_grad=True)
312	
313	    def set_training(self, flag: bool):
314	        self.stem.set_training(flag)
315	        for b in self.blocks:
316	            b.set_training(flag)
317	
318	    def forward(self, X) -> Tensor:
319	        # TODO: run the stem + blocks, global-average-pool, then the (2-bit) linear head.
320	        raise NotImplementedError("QuantCNN.forward")
321	
322	    # ---- parameter collection + checkpoint (provided; do not change the names) ----------
323	    def named_params(self) -> Dict[str, Tensor]:
324	        d: Dict[str, Tensor] = {}
325	        for k, v in self.stem.named_params().items():
326	            d[f"stem.{k}"] = v
327	        for i, b in enumerate(self.blocks):
328	            for k, v in b.named_params().items():
329	                d[f"blocks.{i}.{k}"] = v
330	        d["head.weight"] = self.head_w
331	        d["head.wq.scale"] = self.head_wq.scale
332	        d["head.bias"] = self.head_b
333	        return
…[truncated 11995 chars]
Let me read the remaining parts of the files.

/app/submission/autograd.py

contents
800	def var(a, axis=None, keepdims=False) -> Tensor:
801	    """Population variance over ``axis``: mean((a-mu)^2). Backward: grad * (2/N) * (a - mu)."""
802	    a = _ensure(a)
803	    mu = a.data.mean(axis=axis, keepdims=True)
804	    xc = a.data - mu
805	    out = _mk((xc * xc).mean(axis=axis, keepdims=keepdims), (a,), a.requires_grad)
806	
807	    def _bw():
808	        raise NotImplementedError("var backward")  # TODO
809	
810	    out._backward = _bw
811	    return out
812	
813	
814	def std(a, axis=None, keepdims=False, eps: float = 0.0) -> Tensor:
815	    """Population standard deviation sqrt(var + eps). Backward: grad * (a-mu)/(N*std)."""
816	    a = _ensure(a)
817	    mu = a.data.mean(axis=axis, keepdims=True)
818	    xc = a.data - mu
819	    v = (xc * xc).mean(axis=axis, keepdims=True)
820	    sd = np.sqrt(v + eps)
821	    out_data = sd if keepdims else (np.squeeze(sd, axis=axis) if axis is not None else float(sd.reshape(())))
822	    out = _mk(out_data, (a,), a.requires_grad)
823	
824	    def _bw():
825	        raise NotImplementedError("std backward")  # TODO
826	
827	    out._backward = _bw
828	    return out
829	
830	
831	def gather(a, idx, axis: int) -> Tensor:
832	    """Gather along ``axis`` (numpy take_along_axis). Backward scatter-adds out.grad back at idx."""
833	    a = _ensure(a)
834	    idx = np.asarray(idx)
835	    out = _mk(np.take_along_axis(a.data, idx, axis=axis), (a,), a.requires_grad)
836	
837	    def _bw():
838	        raise NotImplementedError("ga
…[truncated 19850 chars]

/app/submission/nn.py

contents
600	        self.pos = pos
601	
602	    def quant(self, w: Tensor) -> Tensor:
603	        # TODO: return ag.fake_quant_per_channel(w, self.scale, self.neg, self.pos, axis=0)
604	        raise NotImplementedError("PerChannelWeightQuant.quant")
605	
606	    def named_params(self):
607	        return {"scale": self.scale}
608	
609	
610	class AffineActQuant(Module):
611	    """Affine (asymmetric) LSQ activation quantizer with a learnable step ``scale`` and FIXED
612	    integer ``zero_point`` (unsigned grid {0..pos})."""
613	
614	    def __init__(self, neg=A_NEG, pos=A_POS, zero_point=0):
615	        self.scale = Tensor(np.array([1.0]), requires_grad=True)
616	        self.neg = neg
617	        self.pos = pos
618	        self.zero_point = zero_point
619	
620	    def forward(self, x: Tensor) -> Tensor:
621	        # TODO: return ag.fake_quant_affine(x, self.scale, self.zero_point, self.neg, self.pos)
622	        raise NotImplementedError("AffineActQuant.forward")
623	
624	    def named_params(self):
625	        return {"scale": self.scale}
626	
627	
628	# ============================================================ EXTENDED layers (v2)
629	class RMSNorm(Module):
630	    """RMSNorm over the last axis with a per-feature scale ``gamma`` (no bias)."""
631	
632	    def __init__(self, d, eps=1e-5):
633	        self.gamma = Tensor(np.ones(d), requires_grad=True)
634	        self.eps = eps
635	
636	    def forward(self, x: Tensor) -> Tensor:
637	        # TODO: return ag.rms_norm(x, self.
…[truncated 10137 chars]

/app/submission/autograd.py

contents
1300	    N, C, H, W = x.data.shape
1301	    xp = _pad_nchw(x.data, pad)
1302	    Hp, Wp = xp.shape[2], xp.shape[3]
1303	    OH = (Hp - k) // stride + 1
1304	    OW = (Wp - k) // stride + 1
1305	    out_data = np.empty((N, C, OH, OW), dtype=np.float64)
1306	    for oi in range(OH):
1307	        for oj in range(OW):
1308	            out_data[:, :, oi, oj] = xp[:, :, oi * stride:oi * stride + k,
1309	                                        oj * stride:oj * stride + k].mean(axis=(2, 3))
1310	    out = _mk(out_data, (x,), x.requires_grad)
1311	
1312	    def _bw():
1313	        raise NotImplementedError("avgpool2d_s backward")  # TODO
1314	
1315	    out._backward = _bw
1316	    return out
1317	
1318	
1319	def maxpool2d_s(x, k, stride=None, pad=0) -> Tensor:
1320	    """Max pooling with arbitrary ``stride`` (default k) and ``pad`` -> OVERLAPPING windows when
1321	    stride < k (padding is -inf so it never wins). Backward routes each output grad to its window
1322	    argmax, ACCUMULATING into shared positions (np.add.at), then crops the padding. (argmax i/j provided.)"""
1323	    x = _ensure(x)
1324	    stride = k if stride is None else stride
1325	    N, C, H, W = x.data.shape
1326	    if pad > 0:
1327	        xp = np.pad(x.data, ((0, 0), (0, 0), (pad, pad), (pad, pad)),
1328	                    mode="constant", constant_values=-np.inf)
1329	    else:
1330	        xp = x.data
1331	    Hp, Wp = xp.shape[2], xp.shape[3]
1332	    OH = (Hp - k) // stride + 1
1333	    OW = (Wp - k) // 
…[truncated 2440 chars]

/app/submission/optim.py

contents
1	"""Optimizers over autograd ``Tensor`` parameters.
2	
3	Implement the ``# TODO`` update math. Both optimizers update ``param.data`` IN PLACE using
4	``param.grad``. The grader runs one (and several) steps and compares your updated params against
5	its reference within a tight tolerance, so the math must be exact.
6	
7	SGD (with momentum ``mu`` and coupled weight decay ``wd``):
8	    g = grad + wd * param;  v = mu * v + g;  param -= lr * v
9	
10	AdamW (DECOUPLED weight decay -- the decay is applied to the PARAM, not folded into the moments):
11	    m = b1*m + (1-b1)*g;  v = b2*v + (1-b2)*g^2
12	    mhat = m / (1 - b1^t);  vhat = v / (1 - b2^t)        # t = 1-based step count
13	    param -= lr * ( mhat / (sqrt(vhat) + eps) + wd * param )
14	
15	PARAM GROUPS: both optimizers must accept EITHER a flat param list OR a list of
16	``{"params": [...], "weight_decay": wd}`` dicts, so weight decay can be applied to SOME params
17	and not others. This matters for low-bit LSQ QAT: the per-tensor quantizer ``scale`` params,
18	BatchNorm gamma/beta, and biases must be EXCLUDED from weight decay. ``_normalize_groups`` and
19	``split_decay_params`` are provided; honour the per-group weight decay in ``step``.
20	"""
21	from __future__ import annotations
22	
23	import math
24	
25	from typing import Dict, List
26	
27	import numpy as np
28	
29	from autograd import Tensor
30	
31	
32	def split_decay_params(model) -> Dict[str, List[Tensor]]:
33	    """Partition a model's named params into weight
…[truncated 11129 chars]

/app/submission/data.py

/app/submission/train.py

contents
1	"""Image data loading + normalization + batching.
2	
3	The dataset is a procedurally-generated CIFAR-style set: ``X`` is ``uint8`` (N,3,S,S) in [0,255],
4	``y`` is the integer class label in [0, n_classes). The shipped training split is at
5	``/app/data/train.npz``; the SEALED held-out split is regenerated by the verifier (never shipped).
6	
7	Implement the ``# TODO`` bodies (numpy only). The verifier normalizes the held-out split with the
8	SAME transform, so match it exactly.
9	
10	Contract:
11	  load_npz(path) -> (X uint8 (N,3,S,S), y int64 (N,))       [provided]
12	  normalize(X)   -> float64: x = (X/255 - 0.5) / 0.25       [per-channel, the grader's transform]
13	  iter_minibatches(Xn, y, batch_size, rng, shuffle=True) -> yields (xb, yb)
14	"""
15	from __future__ import annotations
16	
17	from typing import Tuple
18	
19	import numpy as np
20	
21	NORM_MEAN = 0.5
22	NORM_STD = 0.25
23	
24	
25	def load_npz(path: str) -> Tuple[np.ndarray, np.ndarray]:
26	    d = np.load(path)
27	    X = np.asarray(d["X"]).astype(np.uint8)
28	    y = np.asarray(d["y"]).astype(np.int64).reshape(-1)
29	    return X, y
30	
31	
32	def normalize(X: np.ndarray) -> np.ndarray:
33	    """uint8 (N,3,S,S) -> float64, x = (X/255 - NORM_MEAN) / NORM_STD."""
34	    # TODO: cast to float, scale to [0,1], subtract NORM_MEAN, divide by NORM_STD.
35	    raise NotImplementedError("normalize")
36	
37	
38	def iter_minibatches(Xn: np.ndarray, y: np.ndarray, batch_size: int,
39	                     rng: np.rando
…[truncated 281 chars]

contents
1	"""Training entry point. Implement the QAT loop, train your INT2 CNN on /app/data/train.npz, and
2	SAVE the checkpoint to /app/submission/qat_model.npz (numpy .npz of the model state_dict: every
3	param + every BN running buffer, by the nn.QuantCNN naming contract).
4	
5	The grader (verify.py) will:
6	  (1) run the conformance suite over your autograd/nn/optim,
7	  (2) BIT-AUDIT every conv/head weight tensor in your checkpoint to <= 4 distinct float values,
8	  (3) load your weights into its OWN QuantCNN and score held-out top-1 on a SEALED split.
9	
10	So at SAVE time you must BAKE the quantized weights back into each ``weight`` tensor (replace it
11	with round(clip(w/s, -W_NEG, W_POS)) * s using the learned wq.scale) so the saved weights already
12	lie on the 2-bit grid and pass the audit. Reaching the top-1 floor at INT-2 needs a real recipe:
13	sensible LSQ STEP-SIZE INITIALIZATION (a default scale of 1.0 quantizes the small init weights to
14	all-zeros -> a dead network at chance), per-tensor learnable scales, weight decay EXCLUDED from the
15	scale/BN/bias params, gradient clipping, a decaying LR, and enough epochs. Naive post-training
16	rounding or under-training lands at chance.
17	
18	This file is a skeleton; the loop body is yours to write.
19	"""
20	from __future__ import annotations
21	
22	import argparse
23	import os
24	import sys
25	
26	import numpy as np
27	
28	sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
29	sys.path.insert(0, "/app")
30	
3
…[truncated 1513 chars]
I'll implement all files now. Starting with autograd.py - writing in pieces due to size constraints.
write · /app/submission/autograd.py
"""Reverse-mode automatic differentiation over numpy arrays."""
from __future__ import annotations

from typing import Callable, Iterable, List, Optional

import numpy as np

_bi_max = max
_bi_min = min


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


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


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):
        if grad is None:
            grad = np.ones_like(self.data)
        self._accum(grad)
        # B
…[truncated 48590 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 implement nn.py:
write · /app/submission/nn.py
"""QAT layers + small INT2 CNN/MLP/SepCNN, built on autograd engine."""
from __future__ import annotations

from typing import Dict, List

import numpy as np

import autograd as ag
from autograd import Tensor

W_NEG, W_POS = 2, 1      # signed weights: {-2,-1,0,1}
A_NEG, A_POS = 0, 3      # unsigned activations (post-relu): {0,1,2,3}


class Module:
    def params(self) -> List[Tensor]:
        return list(self.named_params().values())

    def named_params(self) -> Dict[str, Tensor]:
        raise NotImplementedError

    def buffers(self) -> Dict[str, np.ndarray]:
        return {}

    def __call__(self, *a, **k):
        return self.forward(*a, **k)


def _kaiming(rng, fan_in, shape, gain=1.0):
    return rng.standard_normal(shape) * (gain / np.sqrt(fan_in))


# ===================================================================== generic layers
class Linear(Module):
    def __init__(self, n_in, n_out, rng, bias=True, gain=1.0):
        self.weight = Tensor(_kaiming(rng, n_in, (n_in, n_out), gain), requires_grad=True)
        self.bias = Tensor(np.zeros(n_out), requires_grad=True) if bias else None

    def forward(self, x: Tensor) -> Tensor:
        out = ag.matmul(x, self.weight)
        if self.bias is not None:
            out = ag.add(out, self.bias)
        return out

    def named_params(self):
        d = {"weight": self.weight}
        if self.bias is not None:
            d["bias"] = self.bias
        return d


class ReLU(Module):
    def forward(self, x: Tens
…[truncated 25531 chars]

contents
The file /app/submission/nn.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now implement optim.py, data.py, and train.py:
write · /app/submission/optim.py
"""Optimizers over autograd Tensor parameters."""
from __future__ import annotations

import math

from typing import Dict, List

import numpy as np

from autograd import Tensor


def split_decay_params(model) -> Dict[str, List[Tensor]]:
    decay, no_decay = [], []
    for name, p in model.named_params().items():
        lname = name.lower()
        if lname.endswith("scale") or "bn." in lname or lname.endswith("gamma") \
                or lname.endswith("beta") or lname.endswith("bias"):
            no_decay.append(p)
        else:
            decay.append(p)
    return {"decay": decay, "no_decay": no_decay}


def _normalize_groups(params):
    plist = list(params)
    if plist and isinstance(plist[0], dict):
        return [(list(g["params"]), g.get("weight_decay", None)) for g in plist]
    return [(plist, None)]


class Optimizer:
    def __init__(self, params):
        self._groups = _normalize_groups(params)
        self.params: List[Tensor] = [p for g, _ in self._groups for p in g]

    def zero_grad(self):
        for p in self.params:
            p.grad = None


class SGD(Optimizer):
    def __init__(self, params, lr=0.1, momentum=0.0, weight_decay=0.0):
        super().__init__(params)
        self.lr = lr
        self.momentum = momentum
        self.weight_decay = weight_decay
        self._v = [np.zeros_like(p.data) for p in self.params]

    def step(self):
        idx = 0
        for group, wd_override in self._groups:
            wd = self.weight_decay if wd
…[truncated 10990 chars]

contents
The file /app/submission/optim.py has been updated successfully. (file state is current in your context , no need to Read it back)
write · /app/submission/data.py
"""Image data loading + normalization + batching."""
from __future__ import annotations

from typing import Tuple

import numpy as np

NORM_MEAN = 0.5
NORM_STD = 0.25


def load_npz(path: str) -> Tuple[np.ndarray, np.ndarray]:
    d = np.load(path)
    X = np.asarray(d["X"]).astype(np.uint8)
    y = np.asarray(d["y"]).astype(np.int64).reshape(-1)
    return X, y


def normalize(X: np.ndarray) -> np.ndarray:
    return (X.astype(np.float64) / 255.0 - NORM_MEAN) / NORM_STD


def iter_minibatches(Xn: np.ndarray, y: np.ndarray, batch_size: int,
                     rng: np.random.Generator, shuffle: bool = True):
    N = len(y)
    idx = np.arange(N)
    if shuffle:
        rng.shuffle(idx)
    for start in range(0, N, batch_size):
        batch_idx = idx[start:start + batch_size]
        yield Xn[batch_idx], y[batch_idx]

contents
The file /app/submission/data.py has been updated successfully. (file state is current in your context , no need to Read it back)
Now run the checks to see where we stand:

Run checks to see current state

shell
python3 run_checks.py 2>&1 | tail -30
output
optim/NesterovSGD_5step                  OK    (max_abs=0.0e+00)
  optim/param_groups                       OK  
  optim/split_decay_params                 OK  
  optim/clip_grad_norm_clips               OK    (max_abs=0.0e+00)
  optim/clip_grad_norm_noop                OK    (max_abs=0.0e+00)
  optim/sched_cosine                       OK    (max_abs=0.0e+00)
  optim/sched_warmup                       OK    (max_abs=0.0e+00)
  optim/sched_step                         OK    (max_abs=0.0e+00)
  optim/sched_exponential                  OK    (max_abs=0.0e+00)
  optim/sched_polynomial                   OK    (max_abs=0.0e+00)
  optim/sched_linear                       OK    (max_abs=1.7e-18)
  optim/sched_multistep                    OK    (max_abs=0.0e+00)
  optim/sched_cosine_restarts              OK    (max_abs=0.0e+00)

[integration]  6/6
  integration/qcnn_finite                  OK    (1.787->1.018)
  integration/qcnn_loss_decreases          OK    (1.7869->min 1.0175)
  integration/qmlp_finite                  OK    (1.981->0.237)
  integration/qmlp_loss_decreases          OK    (1.9807->min 0.2374)
  integration/qsepcnn_finite               OK    (1.925->1.655)
  integration/qsepcnn_loss_decreases       OK    (1.9249->min 1.6340)

[data]  2/2
  data/normalize_def                       OK  
  data/iter_minibatches_cover              OK    (covered 23/23)

------------------------------------------------------------------------
autograd_grads 114/115 | quant_grads 21/21 | 
…[truncated 201 chars]
221/222! Let me find the one failure:

Find the failing check

shell
python3 run_checks.py 2>&1 | grep FAIL
output
grad/gather                              FAIL  (max_abs=1.00e+00)
Fix the FAIL lines above (each is a backward/forward/optimizer bug). Re-run until all green, then train.
The gather backward uses wrong indexing. Let me fix it:

/app/submission/autograd.py

− removed
def gather(a, idx, axis: int) -> Tensor:
    a = _ensure(a)
    idx = np.asarray(idx)
    out = _mk(np.take_along_axis(a.data, idx, axis=axis), (a,), a.requires_grad)
    def _bw():
        if a.requires_grad:
            g = np.zeros_like(a.data)
            np.add.at(g, _idx_tuple(idx, axis, a.data.ndim), out.grad)
            a._accum(g)
    out._backward = _bw
    return out


def _idx_tuple(idx, axis, ndim):
    """Convert take_along_axis index to a tuple for np.add.at."""
    slices = [slice(None)] * ndim
    slices[axis] = idx
    return tuple(slices)
+ added
def gather(a, idx, axis: int) -> Tensor:
    a = _ensure(a)
    idx = np.asarray(idx)
    out = _mk(np.take_along_axis(a.data, idx, axis=axis), (a,), a.requires_grad)
    def _bw():
        if a.requires_grad:
            g = np.zeros_like(a.data)
            # Build explicit indices for all dims: broadcast ranges for non-axis dims
            ndim = a.data.ndim
            indices = []
            for ax in range(ndim):
                if ax == axis:
                    indices.append(idx)
                else:
                    shape = [1] * ndim
                    shape[ax] = a.data.shape[ax]
                    indices.append(np.broadcast_to(
                        np.arange(a.data.shape[ax]).reshape(shape), idx.shape))
            np.add.at(g, tuple(indices), out.grad)
            a._accum(g)
    out._backward = _bw
    return out

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

Run checks to confirm all pass

shell
python3 run_checks.py --quiet 2>&1
output
------------------------------------------------------------------------
autograd_grads 115/115 | quant_grads 21/21 | nn_forward 53/53 | optim 25/25 | integration 6/6 | data 2/2
TOTAL  222/222 public checks passing
All public checks pass. Now train qat_model.npz to clear the held-out top-1 threshold (the grader re-checks components with DIFFERENT seeds).
All 222/222 checks passing. Now implement the training loop and train the model:
write · /app/submission/train.py
"""Training entry point for QAT INT-2 CNN."""
from __future__ import annotations

import argparse
import os
import sys

import numpy as np

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
sys.path.insert(0, "/app")

import autograd as ag
import data as D
import optim as O
from nn import QuantCNN, W_NEG, W_POS

WIDTHS = (16, 32)


def init_lsq_scales(model, Xn, n_samples=256, rng=None):
    """Initialize LSQ step sizes from data/weight statistics."""
    if rng is None:
        rng = np.random.default_rng(0)
    # For weight quantizers: scale = max(|w|) / W_POS
    for name, p in model.named_params().items():
        if name.endswith(".weight") and "wq" not in name:
            # find the corresponding wq.scale
            scale_key = name.replace(".weight", ".wq.scale")
            params = model.named_params()
            if scale_key in params:
                w = p.data
                s = np.max(np.abs(w)) / W_POS
                params[scale_key].data[...] = max(s, 1e-4)

    # For activation quantizers: run a few samples through the network to get activation stats
    model.set_training(False)
    idx = rng.choice(len(Xn), min(n_samples, len(Xn)), replace=False)
    Xb = Xn[idx]

    # Hook-based approach: run forward with identity quantizers temporarily
    # Instead: run once without quantization to estimate activation ranges
    # We'll just set act scales to a reasonable initial value
    # Use 3.0 / A_POS as a reasonable init (covers ~3sigma of norma
…[truncated 4167 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)

Train the model for 60 epochs

shell
python3 submission/train.py --epochs 60 2>&1 | tail -25
output
(Bash completed with no output)

Train the model for 60 epochs with full output

shell
python3 /app/submission/train.py --epochs 60 2>&1
output
Exit code 137
/bin/bash: line 1:  1512 Killed                  python3 /app/submission/train.py --epochs 60 2>&1

Time one forward/backward pass

shell
timeout 30 python3 -c "
import sys
sys.path.insert(0, 'submission')
import numpy as np
import autograd as ag
import data as D
from nn import QuantCNN
X, y = D.load_npz('/app/data/train.npz')
Xn = D.normalize(X)
print('Dataset:', X.shape, y.shape, 'n_classes:', len(np.unique(y)))
model = QuantCNN(n_classes=10, widths=(16,32), seed=0)
# Time one forward pass
import time
rng = np.random.default_rng(0)
Xb = Xn[:16]
t0 = time.time()
x = ag.Tensor(Xb)
logits = model(x)
loss = ag.cross_entropy(logits, y[:16])
loss.backward()
t1 = time.time()
print('Forward+backward for batch=16:', t1-t0, 's')
print('loss:', float(loss.data))
" 2>&1
output
Dataset: (2500, 3, 16, 16) (2500,) n_classes: 10
Forward+backward for batch=16: 0.06986355781555176 s
loss: 2.302585092994046

Benchmark one epoch timing

shell
timeout 60 python3 -c "
import sys, time
sys.path.insert(0, 'submission')
import numpy as np
import autograd as ag
import data as D
import optim as O
from nn import QuantCNN

rng = np.random.default_rng(0)
X, y = D.load_npz('/app/data/train.npz')
Xn = D.normalize(X)
model = QuantCNN(n_classes=10, widths=(16,32), seed=0)

# Init scales
for name, p in model.named_params().items():
    if name.endswith('.weight') and 'wq' not in name:
        scale_key = name.replace('.weight', '.wq.scale')
        params = model.named_params()
        if scale_key in params:
            s = np.max(np.abs(p.data)) / 1.0
            params[scale_key].data[...] = max(s, 1e-4)
    if name.endswith('aq.scale'):
        p.data[...] = 3.0/3.0

groups = O.split_decay_params(model)
param_groups = [
    {'params': groups['decay'], 'weight_decay': 1e-4},
    {'params': groups['no_decay'], 'weight_decay': 0.0},
]
optimizer = O.AdamW(param_groups, lr=1e-2, weight_decay=1e-4)

batch_size = 64
t0 = time.time()
for Xb, yb in D.iter_minibatches(Xn, y, batch_size, rng, shuffle=True):
    optimizer.zero_grad()
    x = ag.Tensor(Xb)
    logits = model(x)
    loss = ag.cross_entropy(logits, yb)
    loss.backward()
    O.clip_grad_norm(model.params(), max_norm=1.0)
    optimizer.step()
t1 = time.time()
print(f'One epoch with batch=64: {t1-t0:.2f}s, n_batches={2500//64+1}')
print(f'Loss:', float(loss.data))
" 2>&1
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: 276/278 cases passed  (all milestones pass: False)
  failing milestones: integration (21/23)
FINAL METRIC: held-out INT2 top-1 = 0.8947  >= threshold 0.7

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_d773b47c56b747e0. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_d773b47c56b747e0 · verifier authoritative; classifier explanatory.