Support for Offset Noise in examples (#2753)

* add noise offset

* make style

Author: haofanwang

examples/text_to_image/train_text_to_image.py

@@ -297,6 +297,7 @@ def parse_args():
     parser.add_argument(
         "--enable_xformers_memory_efficient_attention", action="store_true", help="Whether or not to use xformers."
     )
+    parser.add_argument("--noise_offset", type=float, default=0, help="The scale of noise offset.")
 
     args = parser.parse_args()
     env_local_rank = int(os.environ.get("LOCAL_RANK", -1))
@@ -705,6 +706,12 @@ def collate_fn(examples):
 
                 # Sample noise that we'll add to the latents
                 noise = torch.randn_like(latents)
+                if args.noise_offset:
+                    # https://www.crosslabs.org//blog/diffusion-with-offset-noise
+                    noise += args.noise_offset * torch.randn(
+                        (latents.shape[0], latents.shape[1], 1, 1), device=latents.device
+                    )
+
                 bsz = latents.shape[0]
                 # Sample a random timestep for each image
                 timesteps = torch.randint(0, noise_scheduler.num_train_timesteps, (bsz,), device=latents.device)

examples/text_to_image/train_text_to_image_lora.py

@@ -333,6 +333,7 @@ def parse_args():
     parser.add_argument(
         "--enable_xformers_memory_efficient_attention", action="store_true", help="Whether or not to use xformers."
     )
+    parser.add_argument("--noise_offset", type=float, default=0, help="The scale of noise offset.")
 
     args = parser.parse_args()
     env_local_rank = int(os.environ.get("LOCAL_RANK", -1))
@@ -718,6 +719,12 @@ def collate_fn(examples):
 
                 # Sample noise that we'll add to the latents
                 noise = torch.randn_like(latents)
+                if args.noise_offset:
+                    # https://www.crosslabs.org//blog/diffusion-with-offset-noise
+                    noise += args.noise_offset * torch.randn(
+                        (latents.shape[0], latents.shape[1], 1, 1), device=latents.device
+                    )
+
                 bsz = latents.shape[0]
                 # Sample a random timestep for each image
                 timesteps = torch.randint(0, noise_scheduler.num_train_timesteps, (bsz,), device=latents.device)