cub/thread/thread_scan.cuh

File members: cub/thread/thread_scan.cuh

/******************************************************************************
 * Copyright (c) 2011, Duane Merrill.  All rights reserved.
 * Copyright (c) 2011-2018, NVIDIA CORPORATION.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the NVIDIA CORPORATION nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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#pragma once

#include <cub/config.cuh>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cub/thread/thread_operators.cuh>

CUB_NAMESPACE_BEGIN

namespace internal
{

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T
ThreadScanExclusive(T inclusive, T exclusive, T* input, T* output, ScanOp scan_op, Int2Type<LENGTH> /*length*/)
{
#pragma unroll
  for (int i = 0; i < LENGTH; ++i)
  {
    inclusive = scan_op(exclusive, input[i]);
    output[i] = exclusive;
    exclusive = inclusive;
  }

  return inclusive;
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T
ThreadScanExclusive(T* input, T* output, ScanOp scan_op, T prefix, bool apply_prefix = true)
{
  T inclusive = input[0];
  if (apply_prefix)
  {
    inclusive = scan_op(prefix, inclusive);
  }
  output[0]   = prefix;
  T exclusive = inclusive;

  return ThreadScanExclusive(inclusive, exclusive, input + 1, output + 1, scan_op, Int2Type<LENGTH - 1>());
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T
ThreadScanExclusive(T (&input)[LENGTH], T (&output)[LENGTH], ScanOp scan_op, T prefix, bool apply_prefix = true)
{
  return ThreadScanExclusive<LENGTH>((T*) input, (T*) output, scan_op, prefix, apply_prefix);
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T
ThreadScanInclusive(T inclusive, T* input, T* output, ScanOp scan_op, Int2Type<LENGTH> /*length*/)
{
#pragma unroll
  for (int i = 0; i < LENGTH; ++i)
  {
    inclusive = scan_op(inclusive, input[i]);
    output[i] = inclusive;
  }

  return inclusive;
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T ThreadScanInclusive(T* input, T* output, ScanOp scan_op)
{
  T inclusive = input[0];
  output[0]   = inclusive;

  // Continue scan
  return ThreadScanInclusive(inclusive, input + 1, output + 1, scan_op, Int2Type<LENGTH - 1>());
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T ThreadScanInclusive(T (&input)[LENGTH], T (&output)[LENGTH], ScanOp scan_op)
{
  return ThreadScanInclusive<LENGTH>((T*) input, (T*) output, scan_op);
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T
ThreadScanInclusive(T* input, T* output, ScanOp scan_op, T prefix, bool apply_prefix = true)
{
  T inclusive = input[0];
  if (apply_prefix)
  {
    inclusive = scan_op(prefix, inclusive);
  }
  output[0] = inclusive;

  // Continue scan
  return ThreadScanInclusive(inclusive, input + 1, output + 1, scan_op, Int2Type<LENGTH - 1>());
}

template <int LENGTH, typename T, typename ScanOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T
ThreadScanInclusive(T (&input)[LENGTH], T (&output)[LENGTH], ScanOp scan_op, T prefix, bool apply_prefix = true)
{
  return ThreadScanInclusive<LENGTH>((T*) input, (T*) output, scan_op, prefix, apply_prefix);
}

} // namespace internal
CUB_NAMESPACE_END