softmax_compute.h

// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
//
// 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 <vector>
#include "lite/backends/x86/math/softmax.h"
#include "lite/core/kernel.h"
#include "lite/core/op_registry.h"
namespace paddle {
namespace lite {
namespace kernels {
namespace x86 {

static inline int CanonicalAxis(const int axis, const int rank) {
  if (axis < 0) {
    return axis + rank;
  }
  return axis;
}

static inline int SizeToAxis(const int axis, const DDim& dims) {
  int size = 1;
  for (int i = 0; i < axis; i++) {
    size *= dims[i];
  }
  return size;
}

static inline int SizeFromAxis(const int axis, const DDim& dims) {
  int size = 1;
  for (size_t i = axis; i < dims.size(); i++) {
    size *= dims[i];
  }
  return size;
}

template <typename T>
class SoftmaxCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
 public:
  using param_t = operators::SoftmaxParam;

  void Run() override {
    auto& param = *param_.get_mutable<operators::SoftmaxParam>();
    auto& context = ctx_->As<X86Context>();
    CHECK(param.output);
    CHECK(param.x);

    auto* x = param.x;
    auto* output = param.output;
    output->mutable_data<T>();

    const int rank = x->dims().size();
    const int axis = CanonicalAxis(param.axis, rank);
    int axis_dim = x->dims()[axis];
    if (rank == 2 && axis == 1) {
      lite::x86::math::SoftmaxFunctor<lite::TargetType::kX86, T, true>()(
          context, axis_dim, x, output);
    } else {
      const int n = SizeToAxis(axis, x->dims());
      const int d = SizeFromAxis(axis, x->dims());

      DDim x_dims = x->dims();
      DDim out_dims = output->dims();

      DDim shape_2d(std::vector<DDim::value_type>{n, d});
      x->Resize(shape_2d);
      output->Resize(shape_2d);

      lite::x86::math::SoftmaxFunctor<lite::TargetType::kX86, T, true>()(
          context, axis_dim, x, output);
      x->Resize(x_dims);
      output->Resize(out_dims);
    }
  }

  virtual ~SoftmaxCompute() = default;
};

}  // namespace x86
}  // namespace kernels
}  // namespace lite
}  // namespace paddle