/*
 * Copyright (c) 2022, NVIDIA CORPORATION.
 *
 * 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.
 */

#ifndef __SUBTRACT_H
#define __SUBTRACT_H

#pragma once

#include "detail/subtract.cuh"

namespace raft {
namespace linalg {

/**
 * @brief Elementwise scalar subtraction operation on the input buffer
 *
 * @tparam InT     input data-type. Also the data-type upon which the math ops
 *                 will be performed
 * @tparam OutT    output data-type
 * @tparam IdxType Integer type used to for addressing
 *
 * @param out    the output buffer
 * @param in     the input buffer
 * @param scalar the scalar used in the operations
 * @param len    number of elements in the input buffer
 * @param stream cuda stream where to launch work
 */
template <typename InT, typename OutT = InT, typename IdxType = int>
void subtractScalar(OutT* out, const InT* in, InT scalar, IdxType len, cudaStream_t stream)
{
  detail::subtractScalar(out, in, scalar, len, stream);
}

/**
 * @brief Elementwise subtraction operation on the input buffers
 * @tparam InT     input data-type. Also the data-type upon which the math ops
 *                 will be performed
 * @tparam OutT    output data-type
 * @tparam IdxType Integer type used to for addressing
 *
 * @param out    the output buffer
 * @param in1    the first input buffer
 * @param in2    the second input buffer
 * @param len    number of elements in the input buffers
 * @param stream cuda stream where to launch work
 */
template <typename InT, typename OutT = InT, typename IdxType = int>
void subtract(OutT* out, const InT* in1, const InT* in2, IdxType len, cudaStream_t stream)
{
  detail::subtract(out, in1, in2, len, stream);
}

/** Substract single value pointed by singleScalarDev parameter in device memory from inDev[i] and
 * write result to outDev[i]
 * @tparam math_t data-type upon which the math operation will be performed
 * @tparam IdxType Integer type used to for addressing
 * @param outDev the output buffer
 * @param inDev the input buffer
 * @param singleScalarDev pointer to the scalar located in device memory
 * @param len number of elements in the input and output buffer
 * @param stream cuda stream
 * @remark block size has not been tuned
 */
template <typename math_t, typename IdxType = int, int TPB = 256>
void subtractDevScalar(math_t* outDev,
                       const math_t* inDev,
                       const math_t* singleScalarDev,
                       IdxType len,
                       cudaStream_t stream)
{
  detail::subtractDevScalar(outDev, inDev, singleScalarDev, len, stream);
}

};  // end namespace linalg
};  // end namespace raft

#endif