src/operator/numpy/np_window_op.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

/*!
 *  Copyright (c) 2019 by Contributors
 * \file np_window_op.h
 * \brief CPU Implementation of unary op hanning, hamming, blackman window.
 */

#ifndef MXNET_OPERATOR_NUMPY_NP_WINDOW_OP_H_
#define MXNET_OPERATOR_NUMPY_NP_WINDOW_OP_H_

#include <string>
#include <vector>
#include "../tensor/init_op.h"

namespace mxnet {
namespace op {

#ifdef __CUDA_ARCH__
__constant__ const float PI = 3.14159265358979323846;
#else
const float PI = 3.14159265358979323846;
using std::isnan;
#endif

struct NumpyWindowsParam : public dmlc::Parameter<NumpyWindowsParam> {
  dmlc::optional<nnvm::dim_t> M;
  std::string ctx;
  int dtype;
  DMLC_DECLARE_PARAMETER(NumpyWindowsParam) {
    DMLC_DECLARE_FIELD(M)
    .set_default(dmlc::optional<nnvm::dim_t>())
    .describe("Number of points in the output window. "
              "If zero or less, an empty array is returned.");
    DMLC_DECLARE_FIELD(ctx)
    .set_default("")
    .describe("Context of output, in format [cpu|gpu|cpu_pinned](n)."
    "Only used for imperative calls.");
    DMLC_DECLARE_FIELD(dtype)
    .set_default(mshadow::kFloat32)
    MXNET_ADD_ALL_TYPES
    .describe("Data-type of the returned array.");
  }
};

struct hanning_fwd {
  template<typename DType>
  MSHADOW_XINLINE static void Map(index_t i, index_t M, int req, DType* out) {
    if (M == 1) {
      KERNEL_ASSIGN(out[i], req, static_cast<int64_t>(1));
    } else {
      KERNEL_ASSIGN(out[i], req, DType(0.5) - DType(0.5) * math::cos(DType(2 * PI * i / (M - 1))));
    }
  }
};

struct hamming_fwd {
  template<typename DType>
  MSHADOW_XINLINE static void Map(index_t i, index_t M, int req, DType* out) {
    if (M == 1) {
      KERNEL_ASSIGN(out[i], req, static_cast<int64_t>(1));
    } else {
      KERNEL_ASSIGN(out[i], req,
                    DType(0.54) - DType(0.46) * math::cos(DType(2 * PI * i / (M - 1))));
    }
  }
};

struct blackman_fwd {
  template<typename DType>
  MSHADOW_XINLINE static void Map(index_t i, index_t M, int req, DType* out) {
    if (M == 1) {
      KERNEL_ASSIGN(out[i], req, static_cast<int64_t>(1));
    } else {
      KERNEL_ASSIGN(out[i], req, DType(0.42) - DType(0.5) * math::cos(DType(2 * PI * i /(M - 1))) +
          DType(0.08) * math::cos(DType(4 * PI * i /(M - 1))));
    }
  }
};

template<typename xpu, int window_select>
void NumpyWindowCompute(const nnvm::NodeAttrs& attrs,
                        const OpContext& ctx,
                        const std::vector<mxnet::TBlob>& inputs,
                        const std::vector<OpReqType>& req,
                        const std::vector<TBlob>& outputs) {
  using namespace mxnet_op;
  mshadow::Stream<xpu> *s = ctx.get_stream<xpu>();
  const NumpyWindowsParam& param = nnvm::get<NumpyWindowsParam>(attrs.parsed);
  if (param.M.has_value() && param.M.value() <= 0) return;
  MSHADOW_TYPE_SWITCH(outputs[0].type_flag_, DType, {
    if (window_select == 0) {
      Kernel<hanning_fwd, xpu>::Launch(s, outputs[0].Size(), static_cast<int>(param.M.value()),
                                       req[0], outputs[0].dptr<DType>());
    } else if (window_select == 1) {
      Kernel<hamming_fwd, xpu>::Launch(s, outputs[0].Size(), static_cast<int>(param.M.value()),
                                       req[0], outputs[0].dptr<DType>());
    } else if (window_select == 2) {
      Kernel<blackman_fwd, xpu>::Launch(s, outputs[0].Size(), static_cast<int>(param.M.value()),
                                        req[0], outputs[0].dptr<DType>());
    } else {
      LOG(FATAL) << "window_select must be (0, 1, 2)";
    }
  });
}

}  // namespace op
}  // namespace mxnet

#endif  // MXNET_OPERATOR_NUMPY_NP_WINDOW_OP_H_