rnn_util.h

// Copyright (c) 2022 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>

namespace phi {

template <typename TensorType, typename T>
void ResetParameterVector(const std::vector<TensorType>& raw_params_vec,
                          const int& num_layers,
                          const bool& is_bidirec,
                          std::vector<std::vector<T*>>* params_vec) {
  // the parameter raw seuquence is [FWhi, FWhh, BWhi, BWhh] * num_layers
  // + [FBhi, FBhh, BBhi, BBhh] * num_layers, we will reset the parameter to
  // ([FWhi, FWhh, FBhi, FBhh] + [BWhi, BWhh, BBhi, BBhh]) * num_layers
  const int& direction_num = is_bidirec ? 2 : 1;
  const int& layer_weight_size = 4 * direction_num;
  const int& all_weight_size = num_layers * layer_weight_size;
  const int& bias_start_idx = all_weight_size / 2;
  for (int i = 0; i < num_layers; i++) {
    params_vec->at(i).resize(layer_weight_size);
    for (int j = 0; j < layer_weight_size; j++) {
      int k = j % 4;
      const int& section = j / 4;
      int tensor_idx = i * 2 * direction_num + section * 2 + k % 2;
      if (k >= 2) {
        tensor_idx += bias_start_idx;
      }
      using remove_cv_t = typename std::remove_cv<T>::type;
      params_vec->at(i)[j] =
          raw_params_vec[tensor_idx]->template data<remove_cv_t>();
    }
  }
}

}  // namespace phi