chore: format and lint code

Signed-off-by: Rusheel Sharma <rusheelhere@gmail.com>

Author: Rusheel86

monai/losses/unified_focal_loss.py

@@ -262,16 +262,19 @@ def forward(self, y_pred: torch.Tensor, y_true: torch.Tensor) -> torch.Tensor:
         if y_pred.shape[1] == 1:
             y_pred = torch.cat([1 - y_pred, y_pred], dim=1)
 
+        original_y_true = y_true if self.ignore_index is not None else None
+
         if self.to_onehot_y:
+            if self.ignore_index is not None:
+                # Replace ignore_index with valid class before one_hot
+                y_true = torch.where(y_true == self.ignore_index, torch.tensor(0, device=y_true.device), y_true)
             y_true = one_hot(y_true, num_classes=self.num_classes)
         elif y_true.shape[1] == 1 and y_pred.shape[1] == 2:
             y_true = torch.cat([1 - y_true, y_true], dim=1)
 
-        original_y_true_unified = y_true  # Use transformed y_true as baseline if original unavailable
-        mask = create_ignore_mask(original_y_true_unified if self.ignore_index is not None else None, self.ignore_index)
-
-        if mask is not None:
-            y_true = y_true * mask
+        if self.ignore_index is not None:
+            mask = original_y_true == self.ignore_index
+            y_true[mask.expand_as(y_true)] = self.ignore_index
 
         if y_true.shape != y_pred.shape:
             raise ValueError(f"ground truth has different shape ({y_true.shape}) from input ({y_pred.shape})")