Fix get_dummy_wan_inputs for two-expert Wan2.2-I2V-A14B pipeline#427
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ThomasNing wants to merge 2 commits into
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Fix get_dummy_wan_inputs for two-expert Wan2.2-I2V-A14B pipeline#427ThomasNing wants to merge 2 commits into
ThomasNing wants to merge 2 commits into
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get_dummy_wan_inputs (used by WanPipeline.quantize_transformer) assumed a single pipeline.transformer and the single-transformer prepare_latents() signature. WanPipelineI2V_2_2 (Wan2.2-I2V-A14B) is two-expert: it has low_noise_transformer / high_noise_transformer (no .transformer) and a different prepare_latents() signature, so qwix quantization crashed with AttributeError: 'WanPipelineI2V_2_2' object has no attribute 'transformer' and then TypeError: prepare_latents() got an unexpected keyword argument 'vae_scale_factor_temporal'. When pipeline.transformer is absent, build dummy latents directly in the (B, C, F, H, W) layout WanModel.__call__ expects, taking num_channels_latents from an existing expert. The single-transformer path is unchanged. Validated on Wan2.2-I2V-A14B (v6e): quantization now proceeds past these errors into qwix.quantize_model.
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Perseus14
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| if getattr(pipeline, "transformer", None) is not None: | ||
| latents = pipeline.prepare_latents( | ||
| batch_size, | ||
| vae_scale_factor_temporal=pipeline.vae_scale_factor_temporal, | ||
| vae_scale_factor_spatial=pipeline.vae_scale_factor_spatial, | ||
| height=config.height, | ||
| width=config.width, | ||
| num_frames=config.num_frames, | ||
| num_channels_latents=pipeline.transformer.config.in_channels, | ||
| ) | ||
| else: |
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Good catch! Wondering instead of an if/else block, can we make this cleaner and more robust by completely decoupling the dummy generation from the pipeline methods and generate the inputs uniformly for all pipeline variants?
Perseus14
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Jun 24, 2026
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Thanks for the PR. I have added a comment, PTAL!
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Problem
get_dummy_wan_inputs(called byWanPipeline.quantize_transformer→qwix.quantize_model) assumes a singlepipeline.transformerand the single-transformerprepare_latents()signature. The two-expertWanPipelineI2V_2_2(Wan2.2-I2V-A14B) haslow_noise_transformer/high_noise_transformer(no.transformer) and a differentprepare_latents()signature, souse_qwix_quantization=Truecrashes:and, once that's worked around:
Fix
When
pipeline.transformeris absent (two-expert pipeline), build the dummy latents directly in the(B, C, F, H, W)layoutWanModel.__call__expects, takingnum_channels_latentsfrom an existing expert (low_noise_transformer). The single-transformer path is unchanged.Validation
On Wan2.2-I2V-A14B (TPU v6e-16, 1080p, 4-step): with this change, quantization proceeds past both errors above into
qwix.quantize_model(the model forward traces correctly with(latents, timesteps, prompt_embeds)). A separate qwix↔JAX version issue (conv_general_dilated() got an unexpected keyword argument 'out_sharding') then surfaces in our environment — unrelated to this change.