WEBVTT

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An unused value should have zero gradient.

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MLX mapped boolean assignment returns 20.

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Two source values used per example. Third unused.

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Forward is correct. Backward crosses batch boundaries.

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Explicit loop and actual-forward differences agree.

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Synthetic step: wrong gradient raises the loss.

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Forward restarts the source counter per example.

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Patch: count within each row, then add its source offset.

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Official Python wheel reproduces the error.

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C++ patch: 19 scenarios, 255 checks pass.

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Local CPU tests. Synthetic inputs.

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Full-model impact and novelty unestablished.