cross_entropy.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/operator.h"
#include "paddle/framework/tensor.h"
#include "paddle/platform/hostdevice.h"

namespace paddle {
namespace operators {
namespace math {

template <typename T>
struct TolerableValue {
  HOSTDEVICE T operator()(const T& x) const {
    PADDLE_ASSERT(std::is_floating_point<T>::value);
    const T kApproInf = 1e20;

    if (x == INFINITY) return kApproInf;
    if (x == -INFINITY) return -kApproInf;
    return x;
  }
};

template <typename Place, typename T>
class CrossEntropyFunctor {
 public:
  // (TODO caoying) it is much better to use DeviceContext as the first
  // parameter.
  void operator()(const framework::ExecutionContext& context,
                  framework::Tensor* out, const framework::Tensor* prob,
                  const framework::Tensor* labels, const bool softLabel);
};
}  // namespace math
}  // namespace operators
}  // namespace paddle