Use fast_step in DPMux for non-current-rank items + add tests#47
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Randomizez merged 2 commits intoApr 19, 2026
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Cover basic rank selection, state save/restore, fast_step parity with __next__, len delegation, input validation, and iter protocol. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Avoid unnecessary data loading for items belonging to other ranks by calling fast_step() (state advance only) instead of next() (state advance + I/O). With dp_size=N, this skips N-1 data loads per step. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Randomizez
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Apr 19, 2026
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Summary
DPMux.__next__was callingnext()for all ranks, loading data that gets discarded for non-current-rank items. Changed to usefast_step()for other ranks — skips N-1 data loads per step.DPMuxand nextable interfaces (previously uncovered).Discussion
Is
fast_step()sufficient to fully advance state?next()may carry side effects beyond whatfast_step()/update()captures — if anySlowFastNextableimplementation mutates state inside the slow path thatfast_step()doesn't replicate, skippingnext()for non-current-rank items could cause state divergence. However, if we must callnext()to keep state correct, then we're forced to do the expensive work for every rank — which defeats the entire purpose of theSlowFastNextableseparation.Test plan
pytest tests/test_nextable.py— 11/11 passed🤖 Generated with Claude Code