Adding log loss operator (#5854)

* Adding log loss operator

* Removing comments

paddle/operators/log_loss_op.cc

+/* Copyright (c) 2016 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. */
+
+#include "paddle/operators/log_loss_op.h"
+
+namespace paddle {
+namespace operators {
+
+class LogLossOp : public framework::OperatorWithKernel {
+ public:
+  using framework::OperatorWithKernel::OperatorWithKernel;
+
+  void InferShape(framework::InferShapeContext* ctx) const override {
+    PADDLE_ENFORCE(ctx->HasInput("Predicted"),
+                   "Input(Predicted) must be initialized.");
+    PADDLE_ENFORCE(ctx->HasInput("Labels"),
+                   "Input(Labels) must be initialized.");
+
+    auto pred_dims = ctx->GetInputDim("Predicted");
+    auto label_dims = ctx->GetInputDim("Labels");
+
+    PADDLE_ENFORCE_EQ(pred_dims, label_dims);
+    PADDLE_ENFORCE_EQ(pred_dims.size(), 2,
+                      "The rank of Input(Predicted) must be 2 and the shape is "
+                      "[batch_size, 1].");
+    PADDLE_ENFORCE_EQ(pred_dims[1], 1,
+                      "Each row of Input(Predicted) contains a real value, "
+                      "so the 2nd dimension of Input(X) must be 1.");
+
+    ctx->SetOutputDim("Loss", {pred_dims[0], 1});
+    ctx->ShareLoD("Predicted", "Loss");
+  }
+};
+
+template <typename AttrType>
+class LogLossOpMaker : public framework::OpProtoAndCheckerMaker {
+ public:
+  LogLossOpMaker(framework::OpProto* proto,
+                 framework::OpAttrChecker* op_checker)
+      : OpProtoAndCheckerMaker(proto, op_checker) {
+    AddInput("Predicted",
+             "The input value (Predicted) of Log loss op."
+             "Predicted is a 2-D tensor with shape [batch_size, 1].");
+    AddInput("Labels",
+             "The target value (Labels) of Log loss op."
+             "Labels is a 2-D tensor with shape [batch_size, 1].");
+    AddOutput("Loss",
+              "The output tensor with shape [batch_size, 1] "
+              "which represents the log loss.");
+    AddAttr<AttrType>("epsilon", "Epsilon in log loss.");
+    AddComment(R"DOC(
+LogLoss Operator.
+
+Log loss is a loss function used for binary classification. Log Loss quantifies
+the accuracy of a classifier by penalising false classifications. Minimising the
+Log Loss is equivalent to maximising the accuracy of the classifier. We define
+Predicted as the values predicted by our model and Labels as the target ground
+truth value. Log loss can evaluate how close the predicted values are to the
+target. The shapes of Predicted and Labels are both [batch_size, 1].
+The equation is:
+
+$$
+Loss = - Labels * log(Predicted + \epsilon) -
+        (1 - Labels) * log(1 - Predicted + \epsilon)
+$$
+
+)DOC");
+  }
+};
+
+class LogLossGradOp : public framework::OperatorWithKernel {
+ public:
+  using framework::OperatorWithKernel::OperatorWithKernel;
+
+  void InferShape(framework::InferShapeContext* ctx) const override {
+    PADDLE_ENFORCE(ctx->HasInput("Predicted"),
+                   "Input(Predicted) should not be null.");
+    PADDLE_ENFORCE(ctx->HasInput("Labels"),
+                   "Input(Labels) should not be null.");
+    PADDLE_ENFORCE(ctx->HasInput(framework::GradVarName("Loss")),
+                   "Input(Loss@GRAD) should not be null.");
+    PADDLE_ENFORCE(ctx->HasOutput(framework::GradVarName("Predicted")),
+                   "Output(Predicted@GRAD) should not be null.");
+
+    auto pred_dims = ctx->GetInputDim("Predicted");
+    auto label_dims = ctx->GetInputDim("Labels");
+    auto loss_grad_dims = ctx->GetInputDim(framework::GradVarName("Loss"));
+    PADDLE_ENFORCE_EQ(loss_grad_dims, pred_dims);
+
+    auto pred_grad_name = framework::GradVarName("Predicted");
+    ctx->SetOutputDim(pred_grad_name, pred_dims);
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle
+
+namespace ops = paddle::operators;
+REGISTER_OP(log_loss, ops::LogLossOp, ops::LogLossOpMaker<float>, log_loss_grad,
+            ops::LogLossGradOp);
+REGISTER_OP_CPU_KERNEL(log_loss,
+                       ops::LogLossKernel<paddle::platform::CPUPlace, float>);
+REGISTER_OP_CPU_KERNEL(
+    log_loss_grad, ops::LogLossGradKernel<paddle::platform::CPUPlace, float>);

paddle/operators/log_loss_op.cu

+/* Copyright (c) 2016 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. */
+
+#define EIGEN_USE_GPU
+#include "paddle/operators/log_loss_op.h"
+
+namespace ops = paddle::operators;
+REGISTER_OP_GPU_KERNEL(log_loss,
+                       ops::LogLossKernel<paddle::platform::GPUPlace, float>);
+REGISTER_OP_GPU_KERNEL(
+    log_loss_grad, ops::LogLossGradKernel<paddle::platform::GPUPlace, float>);

paddle/operators/log_loss_op.h

+/* Copyright (c) 2016 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. */
+
+#pragma once
+#include "paddle/framework/eigen.h"
+#include "paddle/framework/op_registry.h"
+
+namespace paddle {
+namespace operators {
+
+using Tensor = framework::Tensor;
+template <typename T, int MajorType = Eigen::RowMajor,
+          typename IndexType = Eigen::DenseIndex>
+using EigenVector = framework::EigenVector<T, MajorType, IndexType>;
+
+template <typename Place, typename T, typename AttrType = T>
+class LogLossKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto* loss_out = ctx.Output<Tensor>("Loss");
+
+    loss_out->mutable_data<T>(ctx.GetPlace());
+
+    auto epsilon = static_cast<T>(ctx.Attr<AttrType>("epsilon"));
+
+    auto prediction = EigenVector<T>::Flatten(*ctx.Input<Tensor>("Predicted"));
+    auto label = EigenVector<T>::Flatten(*ctx.Input<Tensor>("Labels"));
+
+    auto loss = EigenVector<T>::Flatten(*loss_out);
+    auto place = ctx.GetEigenDevice<Place>();
+
+    loss.device(place) = (-(label * (prediction + epsilon).log()) -
+                          ((static_cast<T>(1) - label) *
+                           (static_cast<T>(1) - prediction + epsilon).log()));
+  }
+};
+
+template <typename Place, typename T, typename AttrType = T>
+class LogLossGradKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto epsilon = static_cast<T>(ctx.Attr<AttrType>("epsilon"));
+
+    auto prediction = EigenVector<T>::Flatten(*ctx.Input<Tensor>("Predicted"));
+    auto label = EigenVector<T>::Flatten(*ctx.Input<Tensor>("Labels"));
+
+    auto* dloss = ctx.Input<Tensor>(framework::GradVarName("Loss"));
+    auto* dpred = ctx.Output<Tensor>(framework::GradVarName("Predicted"));
+
+    auto dl = EigenVector<T>::Flatten(*dloss);
+    auto place = ctx.GetEigenDevice<Place>();
+
+    if (dpred) {
+      dpred->mutable_data<T>(ctx.GetPlace());
+      auto dx = framework::EigenVector<T>::Flatten(*dpred);
+      dx.device(place) = dl * (-(label / (prediction + epsilon)) +
+                               ((static_cast<T>(1) - label) /
+                                (static_cast<T>(1) - prediction + epsilon)));
+    }
+  }
+};
+
+}  // namespace operators
+}  // namespace paddle

python/paddle/v2/fluid/tests/test_log_loss_op.py

+import unittest
+import numpy as np
+from op_test import OpTest
+
+
+class TestLogLossOp(OpTest):
+    def setUp(self):
+        self.op_type = 'log_loss'
+        samples_num = 32
+
+        predicted = np.random.uniform(0.1, 1.0,
+                                      (samples_num, 1)).astype("float32")
+        labels = np.random.randint(0, 2, (samples_num, 1)).astype("float32")
+        epsilon = 1e-4
+        self.inputs = {
+            'Predicted': predicted,
+            'Labels': labels,
+        }
+
+        self.attrs = {'epsilon': epsilon}
+        loss = -labels * np.log(predicted + epsilon) - (
+            1 - labels) * np.log(1 - predicted + epsilon)
+        self.outputs = {'Loss': loss}
+
+    def test_check_output(self):
+        self.check_output()
+
+    def test_check_grad(self):
+        self.check_grad(['Predicted'], 'Loss', max_relative_error=0.03)
+
+
+if __name__ == '__main__':
+    unittest.main()