Fix division by zero in rescale_noise_cfg causing NaNs during inference#13426
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Akash504-ai wants to merge 3 commits intohuggingface:mainfrom
Open
Fix division by zero in rescale_noise_cfg causing NaNs during inference#13426Akash504-ai wants to merge 3 commits intohuggingface:mainfrom
Akash504-ai wants to merge 3 commits intohuggingface:mainfrom
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Hi @yiyixuxu, this fixes a NaN issue in |
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What does this PR do?
This PR fixes a numerical stability issue in
rescale_noise_cfgthat can lead to division by zero and produce NaN/inf values during inference.Problem
The current implementation performs:
noise_pred_rescaled = noise_cfg * (std_text / std_cfg)
If
std_cfgbecomes zero (e.g., whennoise_cfghas zero variance), this results in division by zero, producing NaNs that can silently corrupt the diffusion process.Solution
A small epsilon value is added to the denominator to ensure numerical stability:
noise_pred_rescaled = noise_cfg * (std_text / (std_cfg + 1e-6))
Scope
This fix is applied consistently across:
src/diffusers/guiders/guider_utils.pysrc/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion.pysrc/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl.pyImpact
std_cfg > 0Fixes #13425
@sayakpaul @yiyixuxu