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Bidirectional local attention omits future neighbors · case 04

Bidirectional local attention omits future neighbors.

Member previewVariant 4 · 3 implementations · 6 checks per implementation

Case contract

For length L and radius R, query i sees keys j when |i-j|<=R, including both directions.

Why this case matters

A small explicit visibility matrix makes sequence-attention boundary behavior reviewable.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixtureActualExpectedOutcome
symmetric neighborhood[[true, false, false, false, false, false], [true, true, false, false, false, false], [false, true, true, false, false, false], [false, false, true, true, false, false], [false, false, false, true, true, false], [false, false, false, false, true, true]][[true, true, false, false, false, false], [true, true, true, false, false, false], [false, true, true, true, false, false], [false, false, true, true, true, false], [false, false, false, true, true, true], [false, false, false, false, true, true]]Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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