// 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.

#include "paddle/phi/kernels/adamw_kernel.h"

#include <vector>

#include "paddle/fluid/framework/tensor_util.h"
#include "paddle/phi/backends/cpu/cpu_context.h"
#include "paddle/phi/common/float16.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/adam_kernel.h"
#include "paddle/phi/kernels/funcs/adam_functors.h"

namespace phi {

template <typename T, typename Context>
void AdamwDenseKernel(const Context& dev_ctx,
                      const DenseTensor& param,
                      const DenseTensor& grad,
                      const DenseTensor& learning_rate,
                      const DenseTensor& moment1,
                      const DenseTensor& moment2,
                      const DenseTensor& beta1_pow,
                      const DenseTensor& beta2_pow,
                      paddle::optional<const DenseTensor&> master_param,
                      paddle::optional<const DenseTensor&> skip_update,
                      const Scalar& beta1,
                      const Scalar& beta2,
                      const Scalar& epsilon,
                      float lr_ratio,
                      float coeff,
                      bool with_decay,
                      bool lazy_mode,
                      int64_t min_row_size_to_use_multithread,
                      bool multi_precision,
                      bool use_global_beta_pow,
                      DenseTensor* param_out,
                      DenseTensor* moment1_out,
                      DenseTensor* moment2_out,
                      DenseTensor* beta1_pow_out,
                      DenseTensor* beta2_pow_out,
                      DenseTensor* master_param_outs) {
  bool skip_update_ = false;
  if (skip_update.is_initialized()) {
    PADDLE_ENFORCE_EQ(
        skip_update->numel(),
        1,
        errors::InvalidArgument("Input(SkipUpdate) size must be 1, but get %d",
                                skip_update->numel()));
    std::vector<bool> skip_update_vec;
    paddle::framework::TensorToVector(*skip_update, dev_ctx, &skip_update_vec);
    skip_update_ = skip_update_vec[0];
  }
  VLOG(3) << "Skip update" << skip_update_;

  if (skip_update_ || !with_decay) {
    AdamDenseKernel<T, Context>(dev_ctx,
                                param,
                                grad,
                                learning_rate,
                                moment1,
                                moment2,
                                beta1_pow,
                                beta2_pow,
                                master_param,
                                skip_update,
                                beta1,
                                beta2,
                                epsilon,
                                lazy_mode,
                                min_row_size_to_use_multithread,
                                multi_precision,
                                use_global_beta_pow,
                                param_out,
                                moment1_out,
                                moment2_out,
                                beta1_pow_out,
                                beta2_pow_out,
                                master_param_outs);
    return;
  }

  auto* param_ =
      master_param.is_initialized() ? master_param.get_ptr() : &param;
  T coeff_ = static_cast<T>(coeff);
  T lr_ratio_ = static_cast<T>(lr_ratio);

  funcs::AdamWFunctor<T, funcs::CPUAdamW> functor(
      coeff_,
      lr_ratio_,
      learning_rate.data<T>(),
      const_cast<T*>(param_->data<T>()));
  functor(param_->numel());

  AdamDenseKernel<T, Context>(dev_ctx,
                              param,
                              grad,
                              learning_rate,
                              moment1,
                              moment2,
                              beta1_pow,
                              beta2_pow,
                              master_param,
                              skip_update,
                              beta1,
                              beta2,
                              epsilon,
                              lazy_mode,
                              min_row_size_to_use_multithread,
                              multi_precision,
                              use_global_beta_pow,
                              param_out,
                              moment1_out,
                              moment2_out,
                              beta1_pow_out,
                              beta2_pow_out,
                              master_param_outs);
}

}  // namespace phi

PD_REGISTER_KERNEL(
    adamw, CPU, ALL_LAYOUT, phi::AdamwDenseKernel, float, double) {}