Fix FDG disabled-level crash and MagCache single-block step reset#21
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Fix FDG disabled-level crash and MagCache single-block step reset#21cursor[bot] wants to merge 2 commits into
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FrequencyDecoupledGuidance appended pred_cond_freq in the disabled-level else branch, causing NameError when the first level was disabled and stale values when later levels were disabled. Use pred_cond_pyramid[level] instead. MagCache single-block models never advanced step_index on cache skips because the head hook returned early without invoking the co-located tail hook. Advance step state from the head hook skip path for single-block setups. Co-authored-by: Simon Lynch <srlynch1@users.noreply.github.com>
Co-authored-by: Simon Lynch <srlynch1@users.noreply.github.com>
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What does this PR do?
Fixes two critical correctness bugs in guidance/cache code paths.
FrequencyDecoupledGuidance NameError / stale pyramid levels
When a frequency level was disabled (e.g.
guidance_scales=[0.0, 7.5]withuse_original_formulation=True), the disabled-level branch appendedpred_cond_freq, which was never assigned for the first disabled level (crash) or was stale from a previous level (wrong reconstruction). The fix usespred_cond_pyramid[level]as intended by the comment.MagCache single-block step_index stuck on skip
Single-block transformers register both head and tail hooks on the same block. On cache skips, the head hook returns early without invoking the tail hook, so
step_indexnever advanced and state never reset afternum_inference_steps. This caused wrong outputs on subsequent inference cycles (e.g. step 2 output 22.0 instead of 24.0). The fix advances step state from the head hook skip path when head/tail are co-located.Tests
tests/guiders/test_frequency_decoupled_guidance.py— disabled first level no longer crashestests/hooks/test_mag_cache.py::test_mag_cache_single_block_step_reset— verifies step reset after two skipsAlso includes a tiny
check_copies.pychange to invoke ruff viapython -m ruffso copy checks work whenruffis not on PATH.Before submitting