add adaptive noise scale

library/custom_train_functions.py

@@ -348,10 +348,28 @@ def get_weighted_text_embeddings(
 # https://wandb.ai/johnowhitaker/multires_noise/reports/Multi-Resolution-Noise-for-Diffusion-Model-Training--VmlldzozNjYyOTU2
 def pyramid_noise_like(noise, device, iterations=6, discount=0.3):
     b, c, w, h = noise.shape
-    u = torch.nn.Upsample(size=(w, h), mode='bilinear').to(device)
+    u = torch.nn.Upsample(size=(w, h), mode="bilinear").to(device)
     for i in range(iterations):
-        r = random.random()*2+2 # Rather than always going 2x, 
-        w, h = max(1, int(w/(r**i))), max(1, int(h/(r**i)))
+        r = random.random() * 2 + 2  # Rather than always going 2x,
+        w, h = max(1, int(w / (r**i))), max(1, int(h / (r**i)))
         noise += u(torch.randn(b, c, w, h).to(device)) * discount**i
-        if w==1 or h==1: break # Lowest resolution is 1x1
-    return noise/noise.std() # Scaled back to roughly unit variance
+        if w == 1 or h == 1:
+            break  # Lowest resolution is 1x1
+    return noise / noise.std()  # Scaled back to roughly unit variance
+
+
+# https://www.crosslabs.org//blog/diffusion-with-offset-noise
+def apply_noise_offset(latents, noise, noise_offset, adaptive_noise_scale):
+    if noise_offset is None:
+        return noise
+    if adaptive_noise_scale is not None:
+        # latent shape: (batch_size, channels, height, width)
+        # abs mean value for each channel
+        latent_mean = torch.abs(latents.mean(dim=(2, 3), keepdim=True))
+
+        # multiply adaptive noise scale to the mean value and add it to the noise offset
+        noise_offset = noise_offset + adaptive_noise_scale * latent_mean
+        noise_offset = torch.clamp(noise_offset, 0.0, None) # in case of adaptive noise scale is negative
+
+    noise = noise + noise_offset * torch.randn((latents.shape[0], latents.shape[1], 1, 1), device=latents.device)
+    return noise

library/train_util.py

@@ -2133,6 +2133,12 @@ def add_training_arguments(parser: argparse.ArgumentParser, support_dreambooth:
         default=0.3,
         help="set discount value for multires noise (has no effect without --multires_noise_iterations) / Multires noiseのdiscount値を設定する（--multires_noise_iterations指定時のみ有効）",
     )
+    parser.add_argument(
+        "--adaptive_noise_scale",
+        type=float,
+        default=None,
+        help="add `latent mean absolute value * this value` to noise_offset (disabled if None, default) / latentの平均値の絶対値 * この値をnoise_offsetに加算する（Noneの場合は無効、デフォルト）",
+    )
     parser.add_argument(
         "--lowram",
         action="store_true",
@@ -2210,6 +2216,11 @@ def verify_training_args(args: argparse.Namespace):
             "noise_offset and multires_noise_iterations cannot be enabled at the same time / noise_offsetとmultires_noise_iterationsを同時に有効にすることはできません"
         )
 
+    if args.adaptive_noise_scale is not None and args.noise_offset is None:
+        raise ValueError(
+            "adaptive_noise_scale requires noise_offset / adaptive_noise_scaleを使用するにはnoise_offsetが必要です"
+        )
+
 
 def add_dataset_arguments(
     parser: argparse.ArgumentParser, support_dreambooth: bool, support_caption: bool, support_caption_dropout: bool