Updated diffusion feature extractor
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@@ -414,15 +414,41 @@ class SDTrainer(BaseSDTrainProcess):
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if self.dfe is not None:
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if self.dfe.version == 1:
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# do diffusion feature extraction on target
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model = self.sd
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if model is not None and hasattr(model, 'get_stepped_pred'):
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stepped_latents = model.get_stepped_pred(noise_pred, noise)
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else:
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# stepped_latents = noise - noise_pred
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# first we step the scheduler from current timestep to the very end for a full denoise
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bs = noise_pred.shape[0]
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noise_pred_chunks = torch.chunk(noise_pred, bs)
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timestep_chunks = torch.chunk(timesteps, bs)
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noisy_latent_chunks = torch.chunk(noisy_latents, bs)
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stepped_chunks = []
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for idx in range(bs):
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model_output = noise_pred_chunks[idx]
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timestep = timestep_chunks[idx]
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self.sd.noise_scheduler._step_index = None
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self.sd.noise_scheduler._init_step_index(timestep)
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sample = noisy_latent_chunks[idx].to(torch.float32)
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sigma = self.sd.noise_scheduler.sigmas[self.sd.noise_scheduler.step_index]
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sigma_next = self.sd.noise_scheduler.sigmas[-1] # use last sigma for final step
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prev_sample = sample + (sigma_next - sigma) * model_output
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stepped_chunks.append(prev_sample)
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stepped_latents = torch.cat(stepped_chunks, dim=0)
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stepped_latents = stepped_latents.to(self.sd.vae.device, dtype=self.sd.vae.dtype)
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pred_features = self.dfe(stepped_latents.float())
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with torch.no_grad():
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rectified_flow_target = noise.float() - batch.latents.float()
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target_features = self.dfe(torch.cat([rectified_flow_target, noise.float()], dim=1))
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target_features = self.dfe(batch.latents.to(self.device_torch, dtype=torch.float32))
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# scale dfe so it is weaker at higher noise levels
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dfe_scaler = 1 - (timesteps.float() / 1000.0).view(-1, 1, 1, 1).to(self.device_torch)
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# do diffusion feature extraction on prediction
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pred_features = self.dfe(torch.cat([noise_pred.float(), noise.float()], dim=1))
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additional_loss += torch.nn.functional.mse_loss(pred_features, target_features, reduction="mean") * \
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self.train_config.diffusion_feature_extractor_weight
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dfe_loss = torch.nn.functional.mse_loss(pred_features, target_features, reduction="none") * \
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self.train_config.diffusion_feature_extractor_weight * dfe_scaler
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additional_loss += dfe_loss.mean()
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elif self.dfe.version == 2:
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# version 2
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# do diffusion feature extraction on target
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