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ppocr/losses/rec_parseq_loss.py

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+# copyright (c) 2020 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.
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import paddle
+from paddle import nn
+
+
+class ParseQLoss(nn.Layer):
+    def __init__(self, **kwargs):
+        super(ParseQLoss, self).__init__()
+
+    def forward(self, predicts, targets):
+        label = targets[1]  # label
+        label_len = targets[2]
+        max_step = paddle.max(label_len).cpu().numpy()[0] + 2
+        tgt = label[:, :max_step]
+
+        logits_list = predicts["logits_list"]
+        pad_id = predicts["pad_id"]
+        eos_id = predicts["eos_id"]
+
+        tgt_out = tgt[:, 1:]
+        loss = 0
+        loss_numel = 0
+        n = (tgt_out != pad_id).sum().item()
+
+        for i, logits in enumerate(logits_list):
+            loss += n * paddle.nn.functional.cross_entropy(
+                input=logits, label=tgt_out.flatten(), ignore_index=pad_id
+            )
+            loss_numel += n
+            if i == 1:
+                tgt_out = paddle.where(condition=tgt_out == eos_id, x=pad_id, y=tgt_out)
+                n = (tgt_out != pad_id).sum().item()
+        loss /= loss_numel
+
+        return {"loss": loss}