apg: normalize diff_norm calculation by tensor size (leejet#1620)

stduhpf · web-flow · commit 138da14cc343 · 2026-06-08T21:56:15.000+08:00
diff --git a/src/runtime/guidance.cpp b/src/runtime/guidance.cpp
@@ -173,8 +173,9 @@ namespace sd::guidance {
         }
 
         float diff_norm = 0.0f;
+        const int standard_res = 2 * 1024 / 8; // Use SDXL as the standard resolution (1024x1024, 8x8 patches, 4=2x2 channels)
         if (params_.norm_threshold > 0.0f) {
-            diff_norm = std::sqrt((deltas * deltas).sum());
+            diff_norm = std::sqrt((deltas * deltas).sum()) * standard_res / std::sqrt(static_cast<float>(deltas.numel()));
         }
 
         float apg_scale_factor = 1.0f;

Original file line number	Diff line number	Diff line change
`@@ -173,8 +173,9 @@ namespace sd::guidance {`
`173`	`173`	`}`
`174`	`174`
`175`	`175`	`float diff_norm = 0.0f;`
	`176`	`+ const int standard_res = 2 * 1024 / 8; // Use SDXL as the standard resolution (1024x1024, 8x8 patches, 4=2x2 channels)`
`176`	`177`	`if (params_.norm_threshold > 0.0f) {`
`177`		`- diff_norm = std::sqrt((deltas * deltas).sum());`
	`178`	`+ diff_norm = std::sqrt((deltas * deltas).sum()) * standard_res / std::sqrt(static_cast<float>(deltas.numel()));`
`178`	`179`	`}`
`179`	`180`
`180`	`181`	`float apg_scale_factor = 1.0f;`