thrust / install /include /cub /thread /thread_sort.cuh
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/******************************************************************************
* Copyright (c) 2011-2021, 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
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******************************************************************************/
#pragma once
#include "../config.cuh"
#include "../util_ptx.cuh"
#include "../util_type.cuh"
CUB_NAMESPACE_BEGIN
template <typename T>
__device__ __forceinline__ void Swap(T &lhs, T &rhs)
{
T temp = lhs;
lhs = rhs;
rhs = temp;
}
/**
* @brief Sorts data using odd-even sort method
*
* The sorting method is stable. Further details can be found in:
* A. Nico Habermann. Parallel neighbor sort (or the glory of the induction
* principle). Technical Report AD-759 248, Carnegie Mellon University, 1972.
*
* @tparam KeyT
* Key type
*
* @tparam ValueT
* Value type. If `cub::NullType` is used as `ValueT`, only keys are sorted.
*
* @tparam CompareOp
* functor type having member `bool operator()(KeyT lhs, KeyT rhs)`
*
* @tparam ITEMS_PER_THREAD
* The number of items per thread
*
* @param[in,out] keys
* Keys to sort
*
* @param[in,out] items
* Values to sort
*
* @param[in] compare_op
* Comparison function object which returns true if the first argument is
* ordered before the second
*/
template <typename KeyT,
typename ValueT,
typename CompareOp,
int ITEMS_PER_THREAD>
__device__ __forceinline__ void
StableOddEvenSort(KeyT (&keys)[ITEMS_PER_THREAD],
ValueT (&items)[ITEMS_PER_THREAD],
CompareOp compare_op)
{
constexpr bool KEYS_ONLY = std::is_same<ValueT, NullType>::value;
#pragma unroll
for (int i = 0; i < ITEMS_PER_THREAD; ++i)
{
#pragma unroll
for (int j = 1 & i; j < ITEMS_PER_THREAD - 1; j += 2)
{
if (compare_op(keys[j + 1], keys[j]))
{
Swap(keys[j], keys[j + 1]);
if (!KEYS_ONLY)
{
Swap(items[j], items[j + 1]);
}
}
} // inner loop
} // outer loop
}
CUB_NAMESPACE_END