From 8bb0fae3beebeda5f049cf87d936e2f9aef8caa4 Mon Sep 17 00:00:00 2001
From: Wenqi Li <wenqil@nvidia.com>
Date: Tue, 25 Jul 2023 22:57:41 +0100
Subject: [PATCH 1/2] Revert "fix `GeneralizedDiceLoss` (#5468)"

This reverts commit e03ecd4f474bec099af56e415dcbfb178164c080.

Signed-off-by: Wenqi Li <wenqil@nvidia.com>
---
 monai/losses/dice.py                |  5 +++--
 tests/test_generalized_dice_loss.py | 12 ++++++------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/monai/losses/dice.py b/monai/losses/dice.py
index 088ad50efd..0f34b3ec5f 100644
--- a/monai/losses/dice.py
+++ b/monai/losses/dice.py
@@ -360,8 +360,9 @@ def forward(self, input: torch.Tensor, target: torch.Tensor) -> torch.Tensor:
             max_values = torch.max(w, dim=1)[0].unsqueeze(dim=1)
             w = w + infs * max_values
 
-        numer = 2.0 * (intersection * w) + self.smooth_nr
-        denom = (denominator * w) + self.smooth_dr
+        final_reduce_dim = 0 if self.batch else 1
+        numer = 2.0 * (intersection * w).sum(final_reduce_dim, keepdim=True) + self.smooth_nr
+        denom = (denominator * w).sum(final_reduce_dim, keepdim=True) + self.smooth_dr
         f: torch.Tensor = 1.0 - (numer / denom)
 
         if self.reduction == LossReduction.MEAN.value:
diff --git a/tests/test_generalized_dice_loss.py b/tests/test_generalized_dice_loss.py
index b8256a41a9..d8ba496d03 100644
--- a/tests/test_generalized_dice_loss.py
+++ b/tests/test_generalized_dice_loss.py
@@ -48,7 +48,7 @@
             "input": torch.tensor([[[-1.0, 0.0, 1.0], [1.0, 0.0, -1.0]], [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]]),
             "target": torch.tensor([[[1.0, 0.0, 0.0]], [[1.0, 1.0, 0.0]]]),
         },
-        0.435035,
+        0.469964,
     ],
     [  # shape: (2, 2, 3), (2, 1, 3)
         {"include_background": True, "to_onehot_y": True, "softmax": True, "smooth_nr": 1e-4, "smooth_dr": 1e-4},
@@ -56,7 +56,7 @@
             "input": torch.tensor([[[-1.0, 0.0, 1.0], [1.0, 0.0, -1.0]], [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]]),
             "target": torch.tensor([[[1.0, 0.0, 0.0]], [[1.0, 1.0, 0.0]]]),
         },
-        0.3837,
+        0.414507,
     ],
     [  # shape: (2, 2, 3), (2, 1, 3)
         {
@@ -71,7 +71,7 @@
             "input": torch.tensor([[[-1.0, 0.0, 1.0], [1.0, 0.0, -1.0]], [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]]),
             "target": torch.tensor([[[1.0, 0.0, 0.0]], [[1.0, 1.0, 0.0]]]),
         },
-        1.5348,
+        0.829015,
     ],
     [  # shape: (2, 2, 3), (2, 1, 3)
         {
@@ -86,7 +86,7 @@
             "input": torch.tensor([[[-1.0, 0.0, 1.0], [1.0, 0.0, -1.0]], [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]]),
             "target": torch.tensor([[[1.0, 0.0, 0.0]], [[1.0, 1.0, 0.0]]]),
         },
-        [[[0.210949], [0.295351]], [[0.599976], [0.428522]]],
+        [[[0.273476]], [[0.555539]]],
     ],
     [  # shape: (2, 2, 3), (2, 1, 3)
         {"include_background": False, "to_onehot_y": True, "smooth_nr": 1e-8, "smooth_dr": 1e-8},
@@ -114,7 +114,7 @@
             "input": torch.tensor([[[0.0, 10.0, 10.0, 10.0], [10.0, 0.0, 0.0, 0.0]]]),
             "target": torch.tensor([[[1, 1, 0, 0]]]),
         },
-        0.26669,
+        0.250023,
     ],
     [  # shape: (2, 1, 2, 2), (2, 1, 2, 2)
         {"include_background": True, "other_act": torch.tanh, "smooth_nr": 1e-4, "smooth_dr": 1e-4},
@@ -136,7 +136,7 @@
             "input": torch.tensor([[[-1.0, 0.0, 1.0], [1.0, 0.0, -1.0]], [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]]),
             "target": torch.tensor([[[1.0, 0.0, 0.0]], [[1.0, 1.0, 0.0]]]),
         },
-        -8.55485,
+        -0.097833,
     ],
 ]
 

From b48c53f38d275ce0a146c5369ec0da69cdfd99c4 Mon Sep 17 00:00:00 2001
From: Wenqi Li <wenqil@nvidia.com>
Date: Tue, 25 Jul 2023 23:01:01 +0100
Subject: [PATCH 2/2] update docstring

Signed-off-by: Wenqi Li <wenqil@nvidia.com>
---
 monai/losses/dice.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/monai/losses/dice.py b/monai/losses/dice.py
index 0f34b3ec5f..4f53e3a7d8 100644
--- a/monai/losses/dice.py
+++ b/monai/losses/dice.py
@@ -268,6 +268,7 @@ def __init__(
             smooth_dr: a small constant added to the denominator to avoid nan.
             batch: whether to sum the intersection and union areas over the batch dimension before the dividing.
                 Defaults to False, intersection over union is computed from each item in the batch.
+                If True, the class-weighted intersection and union areas are first summed across the batches.
 
         Raises:
             TypeError: When ``other_act`` is not an ``Optional[Callable]``.