/* Copyright (c) 2018 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/fluid/operators/batch_norm_op.h"
#include "paddle/fluid/platform/mkldnn_reuse.h"

namespace paddle {
namespace framework {
class Tensor;
}  // namespace framework
namespace platform {
class MKLDNNDeviceContext;
}  // namespace platform
}  // namespace paddle

namespace paddle {
namespace operators {

using mkldnn::memory;
using mkldnn::primitive;
using mkldnn::reorder;
using mkldnn::stream;
using paddle::platform::MKLDNNDeviceContext;
using platform::to_void_cast;

template <typename T>
class BatchNormMKLDNNHandler
    : public platform::MKLDNNHandlerT<T, mkldnn::batch_normalization_forward,
                                      mkldnn::batch_normalization_backward> {
 public:
  BatchNormMKLDNNHandler(const paddle::framework::ExecutionContext &ctx,
                         const platform::MKLDNNDeviceContext &dev_ctx,
                         const mkldnn::engine mkldnn_engine,
                         platform::Place cpu_place, const Tensor *x,
                         const bool global_stats, const bool test_mode,
                         const std::string &unique_name)
      : platform::MKLDNNHandlerT<T, mkldnn::batch_normalization_forward,
                                 mkldnn::batch_normalization_backward>(
            dev_ctx, dev_ctx.GetEngine(), cpu_place,
            platform::CreateKey(framework::vectorize(x->dims()), unique_name)) {
    if (!this->isCached()) {
      const float epsilon = ctx.Attr<float>("epsilon");
      const bool fuse_with_relu = ctx.Attr<bool>("fuse_with_relu");

      PADDLE_ENFORCE_EQ(
          x->layout(), DataLayout::kMKLDNN,
          platform::errors::InvalidArgument("Wrong layout set for X tensor"));
      PADDLE_ENFORCE_NE(
          x->format(), MKLDNNMemoryFormat::undef,
          platform::errors::InvalidArgument("Wrong format set for X tensor"));

      auto src_tz = paddle::framework::vectorize(x->dims());

      // Flags are added by bitwise OR operation
      auto flags = mkldnn::normalization_flags::use_scale_shift;  // 001
      if (global_stats)
        flags |= mkldnn::normalization_flags::use_global_stats;  // 010
      if (fuse_with_relu && test_mode)
        flags |= mkldnn::normalization_flags::fuse_norm_relu;  // 100

      auto md = mkldnn::memory::desc(
          src_tz, platform::MKLDNNGetDataType<T>(),
          platform::MKLDNNFormatForSize(src_tz.size(), x->format()));

      this->AcquireForwardPrimitiveDescriptor(
          global_stats == true ? mkldnn::prop_kind::forward_scoring
                               : mkldnn::prop_kind::forward_training,
          md, epsilon, flags);
    }
  }
  BatchNormMKLDNNHandler(const std::vector<int64_t> &dims, const float &epsilon,
                         const mkldnn::normalization_flags &flags,
                         const MKLDNNMemoryFormat diff_fmt,
                         const MKLDNNMemoryFormat src_fmt,
                         const platform::MKLDNNDeviceContext &dev_ctx,
                         platform::Place cpu_place,
                         const std::string &uniq_name)
      : platform::MKLDNNHandlerT<T, mkldnn::batch_normalization_forward,
                                 mkldnn::batch_normalization_backward>(
            dev_ctx, dev_ctx.GetEngine(), cpu_place,
            platform::CreateKey(dims, uniq_name)) {
    auto diff_dst_md =
        mkldnn::memory::desc(dims, platform::MKLDNNGetDataType<T>(), diff_fmt);
    auto src_md =
        mkldnn::memory::desc(dims, platform::MKLDNNGetDataType<T>(), src_fmt);

    this->AcquireBackwardPrimitiveDescriptor(
        mkldnn::prop_kind::backward, diff_dst_md, src_md, epsilon, flags);
  }

  std::shared_ptr<mkldnn::memory> AcquireScaleShiftMemory(const Tensor *scale,
                                                          const Tensor *shift,
                                                          const bool is_test) {
    auto scaleshift_memory = this->AcquireMemory("@scaleshift_mem_p");
    if (scaleshift_memory == nullptr || !is_test) {
      auto scale_tz = paddle::framework::vectorize(scale->dims());
      const unsigned int C = scale_tz[0];
      PADDLE_ENFORCE_EQ(
          scale_tz.size(), 1,
          platform::errors::InvalidArgument(
              "Dims of scale tensor must be 1, but received scale's size is %d",
              scale_tz.size()));

      auto mem_p = this->AcquireMemoryFromPrimitive(
          this->fwd_pd_->weights_desc(), "@scaleshift_mem_p");

      // MKLDNN requires a single piece of memory for scale and shift/bias data
      auto mem_data_handle = reinterpret_cast<T *>(mem_p->get_data_handle());
      std::copy(scale->data<T>(), scale->data<T>() + C, mem_data_handle);
      std::copy(shift->data<T>(), shift->data<T>() + C, mem_data_handle + C);

      return mem_p;
    }
    return scaleshift_memory;
  }

  std::shared_ptr<mkldnn::memory> AcquireDiffScaleShiftMemory(
      T *diff_scaleshift_data) {
    return this->AcquireMemoryFromPrimitive(this->bwd_pd_->diff_weights_desc(),
                                            diff_scaleshift_data,
                                            "@diff_scaleshift_mem_p");
  }

  std::shared_ptr<mkldnn::memory> AcquireMeanMemory(
      const framework::Tensor *mean) {
    const T *mean_data = mean->data<T>();
    return this->AcquireMemoryFromPrimitive(
        this->fwd_pd_->mean_desc(), to_void_cast<T>(mean_data), "@mean_mem_p");
  }

  std::shared_ptr<mkldnn::memory> AcquireMeanMemory(framework::Tensor *mean) {
    T *mean_data = mean->mutable_data<T>(this->place_,
                                         this->fwd_pd_->mean_desc().get_size());
    return this->AcquireMemoryFromPrimitive(this->fwd_pd_->mean_desc(),
                                            mean_data, "@mean_mem_p");
  }

  std::shared_ptr<mkldnn::memory> AcquireVarianceMemory(
      const framework::Tensor *variance) {
    const T *variance_data = variance->data<T>();
    return this->AcquireMemoryFromPrimitive(this->fwd_pd_->variance_desc(),
                                            to_void_cast<T>(variance_data),
                                            "@variance_mem_p");
  }

  std::shared_ptr<mkldnn::memory> AcquireVarianceMemory(
      framework::Tensor *variance) {
    T *variance_data = variance->mutable_data<T>(
        this->place_, this->fwd_pd_->variance_desc().get_size());
    return this->AcquireMemoryFromPrimitive(this->fwd_pd_->variance_desc(),
                                            variance_data, "@variance_mem_p");
  }
};

template <typename T>
class BatchNormMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
 public:
  void Compute(const framework::ExecutionContext &ctx) const override {
    auto &dev_ctx = ctx.template device_context<MKLDNNDeviceContext>();
    const auto &mkldnn_engine = dev_ctx.GetEngine();

    const bool is_test = ctx.Attr<bool>("is_test");
    const bool use_global_stats = ctx.Attr<bool>("use_global_stats");
    const bool trainable_stats = ctx.Attr<bool>("trainable_statistics");
    const bool test_mode = is_test && (!trainable_stats);
    const bool global_stats = test_mode || use_global_stats;

    const auto *x = ctx.Input<Tensor>("X");
    const auto *scale = ctx.Input<Tensor>("Scale");
    const auto *shift = ctx.Input<Tensor>("Bias");

    auto *y = ctx.Output<Tensor>("Y");
    auto *batch_mean = ctx.Output<Tensor>("SavedMean");
    auto *batch_variance = ctx.Output<Tensor>("SavedVariance");

    BatchNormMKLDNNHandler<T> handler(ctx, dev_ctx, mkldnn_engine,
                                      ctx.GetPlace(), x, global_stats,
                                      test_mode, ctx.OutputName("SavedMean"));

    auto src_memory = handler.AcquireSrcMemory(x);
    auto scaleshift_memory =
        handler.AcquireScaleShiftMemory(scale, shift, is_test);
    auto dst_memory = handler.AcquireDstMemory(y);

    auto batch_norm_p = handler.AcquireForwardPrimitive();

    std::shared_ptr<memory> mean_memory;
    std::shared_ptr<memory> variance_memory;

    if (global_stats) {
      // mean and variance are taken from input Tensor
      const auto *mean = ctx.Input<Tensor>("Mean");
      const auto *variance = ctx.Input<Tensor>("Variance");

      mean_memory = handler.AcquireMeanMemory(mean);
      variance_memory = handler.AcquireVarianceMemory(variance);
    } else {
      // mean and variance are calculated and saved in output Tensor
      mean_memory = handler.AcquireMeanMemory(batch_mean);
      variance_memory = handler.AcquireVarianceMemory(batch_variance);
    }

    y->set_layout(DataLayout::kMKLDNN);
    y->set_format(platform::GetMKLDNNFormat(*dst_memory));

    mkldnn::stream astream(dev_ctx.GetEngine());
    batch_norm_p->execute(astream,
                          {{MKLDNN_ARG_SRC, *src_memory},
                           {MKLDNN_ARG_SCALE_SHIFT, *scaleshift_memory},
                           {MKLDNN_ARG_MEAN, *mean_memory},
                           {MKLDNN_ARG_VARIANCE, *variance_memory},
                           {MKLDNN_ARG_DST, *dst_memory}});
    astream.wait();

    if (!global_stats) {
      auto *mean_out = ctx.Output<Tensor>("MeanOut");
      auto *variance_out = ctx.Output<Tensor>("VarianceOut");
      const float momentum = ctx.Attr<float>("momentum");

      const unsigned int C = paddle::framework::vectorize(scale->dims())[0];

      // mkldnn only compute stats for current batch
      // so we need compute momentum stats via Eigen lib
      EigenVectorArrayMap<T> batch_mean_e(
          batch_mean->mutable_data<T>(ctx.GetPlace()), C);
      EigenVectorArrayMap<T> batch_variance_e(
          batch_variance->mutable_data<T>(ctx.GetPlace()), C);

      EigenVectorArrayMap<T> running_mean_e(
          mean_out->mutable_data<T>(ctx.GetPlace()), C);
      EigenVectorArrayMap<T> running_variance_e(
          variance_out->mutable_data<T>(ctx.GetPlace()), C);

      running_mean_e =
          running_mean_e * momentum + batch_mean_e * (1. - momentum);
      running_variance_e =
          running_variance_e * momentum + batch_variance_e * (1. - momentum);
    }
  }
};

template <typename T>
class BatchNormMKLDNNGradOpKernel : public paddle::framework::OpKernel<T> {
 public:
  void Compute(const paddle::framework::ExecutionContext &ctx) const override {
    auto &dev_ctx = ctx.template device_context<MKLDNNDeviceContext>();
    auto mkldnn_engine = dev_ctx.GetEngine();

    const float epsilon = ctx.Attr<float>("epsilon");

    const auto *x = ctx.Input<Tensor>("X");
    const auto *scale = ctx.Input<Tensor>("Scale");
    const auto *shift = ctx.Input<Tensor>("Bias");
    const auto *batch_mean = ctx.Input<Tensor>("SavedMean");
    const auto *batch_variance = ctx.Input<Tensor>("SavedVariance");
    const auto *diff_y = ctx.Input<Tensor>(framework::GradVarName("Y"));
    auto *diff_x = ctx.Output<Tensor>(framework::GradVarName("X"));
    auto *diff_scale = ctx.Output<Tensor>(framework::GradVarName("Scale"));
    auto *diff_shift = ctx.Output<Tensor>(framework::GradVarName("Bias"));

    PADDLE_ENFORCE_EQ(diff_y->layout(), DataLayout::kMKLDNN,
                      platform::errors::InvalidArgument(
                          "Wrong layout set for Input diff_y tensor"));
    PADDLE_ENFORCE_NE(diff_y->format(), MKLDNNMemoryFormat::undef,
                      platform::errors::InvalidArgument(
                          "Wrong format set for Input diff_y tensor"));

    auto src_tz = paddle::framework::vectorize<int64_t>(x->dims());
    auto scale_tz = paddle::framework::vectorize<int64_t>(scale->dims());
    PADDLE_ENFORCE_EQ(
        scale_tz.size(), 1,
        platform::errors::InvalidArgument(
            "Dims of scale tensor must be 1, but received scale's size is %d",
            scale_tz.size()));

    const unsigned int C = scale_tz[0];

    MKLDNNMemoryFormat dst_format =
        platform::MKLDNNFormatForSize(src_tz.size(), diff_y->format());

    MKLDNNMemoryFormat input_format =
        platform::MKLDNNFormatForSize(src_tz.size(), x->format());

    BatchNormMKLDNNHandler<T> handler(
        src_tz, epsilon, mkldnn::normalization_flags::use_scale_shift,
        dst_format, input_format, dev_ctx, ctx.GetPlace(),
        ctx.InputName("SavedMean"));

    // MKLDNN requires a single piece of memory for scale and shift/bias data
    const size_t scaleshift_size = 2 * C;
    std::vector<T> diff_scaleshift_data;
    diff_scaleshift_data.reserve(scaleshift_size);

    auto src_memory = handler.AcquireSrcMemory(x);
    auto mean_memory = handler.AcquireMeanMemory(batch_mean);
    auto variance_memory = handler.AcquireVarianceMemory(batch_variance);
    auto diff_dst_memory = handler.AcquireDiffDstMemory(diff_y);
    auto scaleshift_memory =
        handler.AcquireScaleShiftMemory(scale, shift, false);
    auto diff_src_memory = handler.AcquireDiffSrcMemory(diff_x);
    auto diff_scaleshift_memory =
        handler.AcquireDiffScaleShiftMemory(diff_scaleshift_data.data());

    // finally create batch_norm backward primitive
    auto batch_norm_bwd_p = handler.AcquireBackwardPrimitive();

    mkldnn::stream astream(dev_ctx.GetEngine());
    batch_norm_bwd_p->execute(
        astream, {{MKLDNN_ARG_SRC, *src_memory},
                  {MKLDNN_ARG_MEAN, *mean_memory},
                  {MKLDNN_ARG_VARIANCE, *variance_memory},
                  {MKLDNN_ARG_DIFF_DST, *diff_dst_memory},
                  {MKLDNN_ARG_SCALE_SHIFT, *scaleshift_memory},
                  {MKLDNN_ARG_DIFF_SRC, *diff_src_memory},
                  {MKLDNN_ARG_DIFF_SCALE_SHIFT, *diff_scaleshift_memory}});
    astream.wait();

    T *diff_scale_data = diff_scale->mutable_data<T>(ctx.GetPlace());
    T *diff_shift_data = diff_shift->mutable_data<T>(ctx.GetPlace());

    // copy back diff sacle/shift to output tensors (diff scale/shift)
    diff_scaleshift_data.resize(scaleshift_size);
    auto it = std::begin(diff_scaleshift_data);
    std::copy(it, std::next(it, C), diff_scale_data);
    std::copy(std::next(it, C), std::end(diff_scaleshift_data),
              diff_shift_data);

    // set layout/format of output tensors
    diff_x->set_layout(DataLayout::kMKLDNN);
    diff_x->set_format(platform::GetMKLDNNFormat(*diff_src_memory));
  }
};
}  // namespace operators
}  // namespace paddle

namespace ops = paddle::operators;
REGISTER_OP_KERNEL(batch_norm, MKLDNN, ::paddle::platform::CPUPlace,
                   ops::BatchNormMKLDNNOpKernel<float>);
REGISTER_OP_KERNEL(batch_norm_grad, MKLDNN, ::paddle::platform::CPUPlace,
                   ops::BatchNormMKLDNNGradOpKernel<float>);
