checkpoint_merger community pipeline: add block weighted and module-specific alpha options

[damian0815]

Some enhancements for the checkpoint_merger community pipeline cc @Abhinay1997

• Different modules can be merged with different alphas via the module_override_alphas kwarg (eg {'unet': 0.2, 'text_encoder': 0.6})
• Block-weighted merges, whereby a different weight can be used for different layers within the unet via blocks kwarg (eg [0,0,0,0,0,0,0,0,0,0,0,0,0.5,1,1,1,1,1,1,1,1,1,1,1,1]). Specify 12 weights for the down blocks (counting from the input layer), 1 weight for the middle block, and 12 weights for the up blocks (counting from the middle layer). You can find an explanation of block-weighted merging here (cw: waifus), and some weight presets to use here (illustrated here).

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint.

[damian0815]

@Abhinay1997 re: your idea to make the block weights target class dynamic, i'm not sure that will work - the layer → block weighting index logic is very brittle and as-is only works for the unet (and it may stop working for SD3.0). eg : https://github.com/huggingface/diffusers/blob/01eff5b282f5cba54fcb0b799b94ae162ad69acb/examples/community/checkpoint_merger.py#L25

[Abhinay1997]

@damian0815, Yes what you said makes sense. For now, I think this is a good feature to be added to Checkpoint Merger. We'll have to figure out fixes to the block_weight dict lookup in case of mismatch with later diffusion models.

Gently pining @patrickvonplaten to review and add your thoughts.

[Abhinay1997]

@pcuenca gently pinging you to add your thoughts on this

[patrickvonplaten]

This looks good to me! Happy to go ahead with the PR if you like (cc @damian0815 and @Abhinay1997 )

[Abhinay1997]

@damian0815 I'm good with the changes. Can you move this from draft to a final PR ?

@patrickvonplaten, can we have multiple contributors in the README.md for a community pipeline ? This is a big change and I think it's only fair that damian0815 is listed as a contributor to CheckpointMergerPipeline.

[patrickvonplaten]

@damian0815 I'm good with the changes. Can you move this from draft to a final PR ?

@patrickvonplaten, can we have multiple contributors in the README.md for a community pipeline ? This is a big change and I think it's only fair that damian0815 is listed as a contributor to CheckpointMergerPipeline.

Sure, feel free to change :-)

[patrickvonplaten]

@damian0815,

Let me know if good to merge for you

[damian0815]

ahh @patrickvonplaten no not yet, there's some bug fixes in my other lib grate (https://github.com/damian0815/grate/blob/main/src/sdgrate/checkpoint_merger_mbw.py) that i need to find some time to copy over and test

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[Abhinay1997]

@damian0815, do let me know if there’s anything I can help on incase you have time constraints :)

[damian0815]

@damian0815, do let me know if there’s anything I can help on incase you have time constraints :)

uhh, yes actually - you could port the changes from https://github.com/damian0815/grate/blob/main/src/sdgrate/checkpoint_merger_mbw.py here (actually it should be enough to just copy/paste the whole file)

[damian0815]

however FYI snapshot_download is an ill-advised way of downloading models, because it will download eeeeeverything - if the model has .safetensors and .bin files you'll end up downloading 9GB of data for a 4.5GB model. and depending on if/how there's an fp16 revision of the model that might get downloaded too - 11GB of data for a 4.5GB model, potentially more. The snapshot_download should really be replaced with a call to StableDiffusionPipeline.from_pretrained(...) and then read off the individual components eg pipeline.unet, pipeline.text_encoder etc rather than attempting to load the files by hand from disk.

[patrickvonplaten]

@damian0815 BTW we have a download function now as well: https://huggingface.co/docs/diffusers/main/en/api/diffusion_pipeline#diffusers.DiffusionPipeline.download

[Abhinay1997]

Hi @damian0815 ! Thanks for the inputs. I'll add your changes over the weekend and test. As for the snapshot_download, it was a tradeoff at that time to not load all the pipelines to memory at once.

However given that we have DiffusionPipeline.download now, things are a lot easier. Let me make the changes after I port your changes here. Thanks for suggesting this @patrickvonplaten :)

Can't do it till the weekend though. 🥲

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[bghira]

=[

[HamnaAkram]

Hi! is there an update to this issue? I would like to use the checkpoint merger pipeline for a project but can't seem to find if it has been completed or not?

[Abhinay1997]

@HamnaAkram you can find the checkpoint merger pipeline in the community pipelines. This issue was raised for an enhancement to the original.

[HamnaAkram]

Thanks for pointing me in the right direction but I have noticed an issue with the existing pipeline. When I initialize alpha=0, the merged model and the original first model should be identical and if alpha=1 merged model should be equivalent to second model. However, this is not the case. After merging the models at alpha=0 or 1 they become nonidentical. I would love to hear any feedback regarding that.

[Abhinay1997]

@HamnaAkram that's weird. Can you open a new issue (helps others to find it in the future.) with a code sample ? Please include any output logs and the checkpoint names or model_index.json files if possible.

I'll try to reproduce it.