fix dit weights convert to ppdiffusers (PaddlePaddle#759)

Author: nemonameless

ppdiffusers/examples/class_conditional_image_generation/DiT/tools/convert_dit_to_ppdiffusers.py

@@ -44,7 +44,9 @@
 def main(args):
     num_layers, hidden_size, patch_size, num_heads = arch_settings[args.model_name]
 
-    state_dict = paddle.load(args.model_weights)
+    state_dict_prefix = paddle.load(args.model_weights)
+    state_dict = {k.replace("transformer.", ""): v for k, v in state_dict_prefix.items()}
+    del state_dict_prefix
 
     state_dict["pos_embed.proj.weight"] = state_dict["x_embedder.proj.weight"]
     state_dict["pos_embed.proj.bias"] = state_dict["x_embedder.proj.bias"]
@@ -158,7 +160,7 @@ def main(args):
     pipeline = DiTPipeline(transformer=transformer, vae=vae, scheduler=scheduler)
 
     if args.save:
-        pipeline.save_pretrained(args.checkpoint_path)
+        pipeline.save_pretrained(args.checkpoint_path, safe_serialization=False)
 
 
 if __name__ == "__main__":