update as official impl

library/sdxl_original_unet.py

@@ -998,21 +998,25 @@ class SdxlUNet2DConditionModel(nn.Module):
 
         # FreeU
         self.freeU = False
-        self.freeUSl = 0.5
-        self.freeURThres = 0.5
-        self.freeUBl = 0.5
+        self.freeUB1 = 1.0
+        self.freeUB2 = 1.0
+        self.freeUS1 = 1.0
+        self.freeUS2 = 1.0
+        self.freeURThres = 1
 
     # implementation of FreeU
     # FreeU: Free Lunch in Diffusion U-Net  https://arxiv.org/abs/2309.11497
 
-    def set_free_u_enabled(self, enabled: bool, bl=0.5, sl=0.5, rthresh=0.5):
-        print(f"FreeU: {enabled}, bl={bl}, sl={sl}, rthresh={rthresh}")
+    def set_free_u_enabled(self, enabled: bool, b1=1.0, b2=1.0, s1=1.0, s2=1.0, rthresh=1):
+        print(f"FreeU: {enabled}, b1={b1}, b2={b2}, s1={s1}, s2={s2}, rthresh={rthresh}")
         self.freeU = enabled
-        self.freeUSl = sl
+        self.freeUB1 = b1
+        self.freeUB2 = b2
+        self.freeUS1 = s1
+        self.freeUS2 = s2
         self.freeURThres = rthresh
-        self.freeUBl = bl
 
-    def spectral_modulation(self, skip_feature, sl=0.5, rthresh=0.5):
+    def spectral_modulation(self, skip_feature, sl=1.0, rthresh=1):
         """
         スキップ特徴を周波数領域で修正する関数
 
@@ -1024,6 +1028,9 @@ class SdxlUNet2DConditionModel(nn.Module):
 
         import torch.fft
 
+        r""" 
+        # 論文に従った実装
+
         org_dtype = skip_feature.dtype
         if org_dtype == torch.bfloat16:
             skip_feature = skip_feature.to(torch.float32)
@@ -1060,9 +1067,35 @@ class SdxlUNet2DConditionModel(nn.Module):
         modified_skip_feature = torch.fft.ifftn(F_prime, dim=(2, 3))
 
         modified_skip_feature = modified_skip_feature.real  # 実部のみを取得
+        """
 
-        if org_dtype == torch.bfloat16:
-            modified_skip_feature = modified_skip_feature.to(org_dtype)
+        # 公式リポジトリの実装
+
+        org_dtype = skip_feature.dtype
+
+        x = skip_feature
+        threshold = rthresh
+        scale = sl
+
+        # FFT
+        x_freq = torch.fft.fftn(x.float(), dim=(-2, -1))
+        x_freq = torch.fft.fftshift(x_freq, dim=(-2, -1))
+
+        B, C, H, W = x_freq.shape
+        mask = torch.ones((B, C, H, W), device=x.device)
+
+        crow, ccol = H // 2, W // 2
+        mask[..., crow - threshold : crow + threshold, ccol - threshold : ccol + threshold] = scale
+        x_freq = x_freq * mask
+
+        # IFFT
+        x_freq = torch.fft.ifftshift(x_freq, dim=(-2, -1))
+        x_filtered = torch.fft.ifftn(x_freq, dim=(-2, -1)).real
+
+        modified_skip_feature = x_filtered
+
+        # if org_dtype == torch.bfloat16:
+        modified_skip_feature = modified_skip_feature.to(org_dtype)
 
         return modified_skip_feature
 
@@ -1151,7 +1184,12 @@ class SdxlUNet2DConditionModel(nn.Module):
             h = call_module(module, h, emb, context)
 
             if self.freeU:
-                h_mod = self.spectral_modulation(h, self.freeUSl, self.freeURThres)
+                ch = h.shape[1]
+                s = self.freeUS1 if ch == 1280 else (self.freeUS2 if ch == 640 else 1.0)
+                if s == 1.0:
+                    h_mod = h
+                else:
+                    h_mod = self.spectral_modulation(h, s, self.freeURThres)
                 hs.append(h_mod)
             else:
                 hs.append(h)
@@ -1161,7 +1199,12 @@ class SdxlUNet2DConditionModel(nn.Module):
         for module in self.output_blocks:
             if self.freeU:
                 ch = h.shape[1]
-                h[:, : ch // 2] = h[:, : ch // 2] * self.freeUBl
+                if ch == 1280:
+                    h[:, : ch // 2] = h[:, : ch // 2] * self.freeUB1
+                elif ch == 640:
+                    h[:, : ch // 2] = h[:, : ch // 2] * self.freeUB2
+                # else:
+                #     print(f"disable freeU: {ch}")
 
             h = torch.cat([h, hs.pop()], dim=1)
             h = call_module(module, h, emb, context)

sdxl_gen_img.py

@@ -1523,7 +1523,7 @@ def main(args):
 
     # freeU
     # unet.set_free_u_enabled(False, 1.0, 1.0, 0)
-    unet.set_free_u_enabled(True, 1.4, 1.0, 10)
+    unet.set_free_u_enabled(True, 1.1, 1.2, 0.9, 0.2)
 
     # networkを組み込む
     if args.network_module: