cub/warp/warp_reduce.cuh
File members: cub/warp/warp_reduce.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;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************/
#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>
#include <cub/util_type.cuh>
#include <cub/warp/specializations/warp_reduce_shfl.cuh>
#include <cub/warp/specializations/warp_reduce_smem.cuh>
#include <cuda/std/type_traits>
CUB_NAMESPACE_BEGIN
template <typename T, int LOGICAL_WARP_THREADS = CUB_PTX_WARP_THREADS, int LEGACY_PTX_ARCH = 0>
class WarpReduce
{
private:
/******************************************************************************
* Constants and type definitions
******************************************************************************/
enum
{
IS_ARCH_WARP = (LOGICAL_WARP_THREADS == CUB_WARP_THREADS(0)),
IS_POW_OF_TWO = PowerOfTwo<LOGICAL_WARP_THREADS>::VALUE,
};
public:
#ifndef _CCCL_DOXYGEN_INVOKED // Do not document
using InternalWarpReduce =
::cuda::std::_If<IS_POW_OF_TWO, WarpReduceShfl<T, LOGICAL_WARP_THREADS>, WarpReduceSmem<T, LOGICAL_WARP_THREADS>>;
#endif // _CCCL_DOXYGEN_INVOKED
private:
using _TempStorage = typename InternalWarpReduce::TempStorage;
/******************************************************************************
* Thread fields
******************************************************************************/
_TempStorage& temp_storage;
/******************************************************************************
* Utility methods
******************************************************************************/
public:
struct TempStorage : Uninitialized<_TempStorage>
{};
_CCCL_DEVICE _CCCL_FORCEINLINE WarpReduce(TempStorage& temp_storage)
: temp_storage(temp_storage.Alias())
{}
_CCCL_DEVICE _CCCL_FORCEINLINE T Sum(T input)
{
return InternalWarpReduce(temp_storage).template Reduce<true>(input, LOGICAL_WARP_THREADS, ::cuda::std::plus<>{});
}
_CCCL_DEVICE _CCCL_FORCEINLINE T Sum(T input, int valid_items)
{
// Determine if we don't need bounds checking
return InternalWarpReduce(temp_storage).template Reduce<false>(input, valid_items, ::cuda::std::plus<>{});
}
template <typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T HeadSegmentedSum(T input, FlagT head_flag)
{
return HeadSegmentedReduce(input, head_flag, ::cuda::std::plus<>{});
}
template <typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T TailSegmentedSum(T input, FlagT tail_flag)
{
return TailSegmentedReduce(input, tail_flag, ::cuda::std::plus<>{});
}
template <typename ReductionOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T Reduce(T input, ReductionOp reduction_op)
{
return InternalWarpReduce(temp_storage).template Reduce<true>(input, LOGICAL_WARP_THREADS, reduction_op);
}
template <typename ReductionOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T Reduce(T input, ReductionOp reduction_op, int valid_items)
{
return InternalWarpReduce(temp_storage).template Reduce<false>(input, valid_items, reduction_op);
}
template <typename ReductionOp, typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T HeadSegmentedReduce(T input, FlagT head_flag, ReductionOp reduction_op)
{
return InternalWarpReduce(temp_storage).template SegmentedReduce<true>(input, head_flag, reduction_op);
}
template <typename ReductionOp, typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T TailSegmentedReduce(T input, FlagT tail_flag, ReductionOp reduction_op)
{
return InternalWarpReduce(temp_storage).template SegmentedReduce<false>(input, tail_flag, reduction_op);
}
};
#ifndef _CCCL_DOXYGEN_INVOKED // Do not document
template <typename T, int LEGACY_PTX_ARCH>
class WarpReduce<T, 1, LEGACY_PTX_ARCH>
{
private:
using _TempStorage = cub::NullType;
public:
struct InternalWarpReduce
{
struct TempStorage : Uninitialized<_TempStorage>
{};
_CCCL_DEVICE _CCCL_FORCEINLINE InternalWarpReduce(TempStorage& /*temp_storage */) {}
template <bool ALL_LANES_VALID, typename ReductionOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T Reduce(T input, int /* valid_items */, ReductionOp /* reduction_op */)
{
return input;
}
template <bool HEAD_SEGMENTED, typename FlagT, typename ReductionOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T SegmentedReduce(T input, FlagT /* flag */, ReductionOp /* reduction_op */)
{
return input;
}
};
using TempStorage = typename InternalWarpReduce::TempStorage;
_CCCL_DEVICE _CCCL_FORCEINLINE WarpReduce(TempStorage& /*temp_storage */) {}
_CCCL_DEVICE _CCCL_FORCEINLINE T Sum(T input)
{
return input;
}
_CCCL_DEVICE _CCCL_FORCEINLINE T Sum(T input, int /* valid_items */)
{
return input;
}
template <typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T HeadSegmentedSum(T input, FlagT /* head_flag */)
{
return input;
}
template <typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T TailSegmentedSum(T input, FlagT /* tail_flag */)
{
return input;
}
template <typename ReductionOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T Reduce(T input, ReductionOp /* reduction_op */)
{
return input;
}
template <typename ReductionOp>
_CCCL_DEVICE _CCCL_FORCEINLINE T Reduce(T input, ReductionOp /* reduction_op */, int /* valid_items */)
{
return input;
}
template <typename ReductionOp, typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T HeadSegmentedReduce(T input, FlagT /* head_flag */, ReductionOp /* reduction_op */)
{
return input;
}
template <typename ReductionOp, typename FlagT>
_CCCL_DEVICE _CCCL_FORCEINLINE T TailSegmentedReduce(T input, FlagT /* tail_flag */, ReductionOp /* reduction_op */)
{
return input;
}
};
#endif // _CCCL_DOXYGEN_INVOKED
CUB_NAMESPACE_END