add dml

ppcls/loss/dmlloss.py

+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import paddle
+import paddle.nn as nn
+import paddle.nn.functional as F
+
+
+class DMLLoss(nn.Layer):
+    """
+    DMLLoss
+    """
+
+    def __init__(self, act="softmax"):
+        super().__init__()
+        if act is not None:
+            assert act in ["softmax", "sigmoid"]
+        if act == "softmax":
+            self.act = nn.Softmax(axis=-1)
+        elif act == "sigmoid":
+            self.act = nn.Sigmoid()
+        else:
+            self.act = None
+
+    def forward(self, out1, out2):
+        if self.act is not None:
+            out1 = self.act(out1)
+            out2 = self.act(out2)
+
+        log_out1 = paddle.log(out1)
+        log_out2 = paddle.log(out2)
+        loss = (F.kl_div(
+            log_out1, out2, reduction='batchmean') + F.kl_div(
+                log_out2, out1, reduction='batchmean')) / 2.0
+        return {"DMLLoss": loss}