FA-98203 / Attention mask construction / Member archive
Causal position does not reset at segment boundaries · case 03
Causal position does not reset at segment boundaries.
Case contract
Each entry is [segment_id, local_position]; visible iff IDs match and key local position<=query local position.
Why this case matters
A small explicit visibility matrix makes sequence-attention boundary behavior reviewable.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| reset and isolate | [[true, false, false, false, false], [true, true, false, false, false], [true, true, true, false, false], [true, true, true, true, false], [true, true, true, true, true]] | [[true, false, false, false, false], [true, true, false, false, false], [true, true, true, false, false], [false, false, false, true, false], [false, false, false, true, true]] | Failed |
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