Fix Z-Image FP16 overflow via downscaling #11187
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vanDuven
requested review from
Kosinkadink,
comfyanonymous and
guill
as code owners
Collaborator
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this will get looked at and potentially merged after next stable! |
|
Does this fix the fried/low-quality images with lumina 2 in fp16? |
Owner
|
The reason I don't enable fp16 in lumina2 is because the neta yume 3.5 model breaks with fp16 + my clamping. It also breaks using the downscaling in this PR. |
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This PR improves FP16 stability for Z-Image by using scaling instead of clamping.
Because the tensor passes through
LinearandRMSNorm, the fp16 tensor can be scaled down to prevent overflow.The scale value(2^x) is based on testing.
No noticeable impact on inference speed.
Tested with: Z-Image and Lumina 2.
The
clamp_fp16function can be safely removed or stay just in case.workflow.json