Fixed noise calculation for v-prediction

1 files changed, 20 insertions, 9 deletions

diff --git a/textual_inversion.py b/textual_inversion.py
index 20b1617..fa7ae42 100644
--- a/textual_inversion.py
+++ b/textual_inversion.py
@@ -439,7 +439,7 @@ class Checkpointer:
         with torch.autocast("cuda"), torch.inference_mode():
             for pool, data, latents in [("stable", val_data, stable_latents), ("val", val_data, None), ("train", train_data, None)]:
                 all_samples = []
-                file_path = samples_path.joinpath(pool, f"step_{step}.png")
+                file_path = samples_path.joinpath(pool, f"step_{step}.jpg")
                 file_path.parent.mkdir(parents=True, exist_ok=True)
 
                 data_enum = enumerate(data)
@@ -568,10 +568,6 @@ def main():
     # Initialise the newly added placeholder token with the embeddings of the initializer token
     token_embeds = text_encoder.get_input_embeddings().weight.data
     original_token_embeds = token_embeds.detach().clone().to(accelerator.device)
-    initializer_token_embeddings = text_encoder.get_input_embeddings()(initializer_token_ids)
-
-    for (token_id, embeddings) in zip(placeholder_token_id, initializer_token_embeddings):
-        token_embeds[token_id] = embeddings
 
     if args.resume_checkpoint is not None:
         token_embeds[placeholder_token_id] = torch.load(args.resume_checkpoint)[args.placeholder_token]
@@ -817,6 +813,18 @@ def main():
     )
     global_progress_bar.set_description("Total progress")
 
+    def get_loss(noise_pred, noise, latents, timesteps):
+        if noise_scheduler.config.prediction_type == "v_prediction":
+            timesteps = timesteps.view(-1, 1, 1, 1)
+            alphas_cumprod = noise_scheduler.alphas_cumprod[timesteps]
+            alpha_t = torch.sqrt(alphas_cumprod)
+            sigma_t = torch.sqrt(1 - alphas_cumprod)
+            target = alpha_t * noise - sigma_t * latents
+        else:
+            target = noise
+
+        return F.mse_loss(noise_pred.float(), target.float(), reduction="mean")
+
     try:
         for epoch in range(num_epochs):
             local_progress_bar.set_description(f"Epoch {epoch + 1} / {num_epochs}")
@@ -854,19 +862,20 @@ def main():
 
                     if args.num_class_images != 0:
                         # Chunk the noise and noise_pred into two parts and compute the loss on each part separately.
+                        latents, latents_prior = torch.chunk(noise_pred, 2, dim=0)
                         noise_pred, noise_pred_prior = torch.chunk(noise_pred, 2, dim=0)
                         noise, noise_prior = torch.chunk(noise, 2, dim=0)
 
                         # Compute instance loss
-                        loss = F.mse_loss(noise_pred, noise, reduction="none").mean([1, 2, 3]).mean()
+                        loss = get_loss(noise_pred, noise, latents, timesteps)
 
                         # Compute prior loss
-                        prior_loss = F.mse_loss(noise_pred_prior, noise_prior, reduction="none").mean([1, 2, 3]).mean()
+                        prior_loss = get_loss(noise_pred_prior, noise_prior, latents_prior, timesteps)
 
                         # Add the prior loss to the instance loss.
                         loss = loss + args.prior_loss_weight * prior_loss
                     else:
-                        loss = F.mse_loss(noise_pred, noise, reduction="none").mean([1, 2, 3]).mean()
+                        loss = get_loss(noise_pred, noise, latents, timesteps)
 
                     accelerator.backward(loss)
 
@@ -922,6 +931,8 @@ def main():
 
             accelerator.wait_for_everyone()
 
+            print(token_embeds[placeholder_token_id])
+
             text_encoder.eval()
             val_loss = 0.0
 
@@ -945,7 +956,7 @@ def main():
 
                     noise_pred, noise = accelerator.gather_for_metrics((noise_pred, noise))
 
-                    loss = F.mse_loss(noise_pred, noise, reduction="none").mean([1, 2, 3]).mean()
+                    loss = get_loss(noise_pred, noise, latents, timesteps)
 
                     loss = loss.detach().item()
                     val_loss += loss