cub/thread/thread_operators.cuh
File members: cub/thread/thread_operators.cuh
/******************************************************************************
* Copyright (c) 2011, Duane Merrill. All rights reserved.
* Copyright (c) 2011-2025, 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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*
******************************************************************************/
/******************************************************************************
* Simple functor operators
******************************************************************************/
#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/util_type.cuh>
#include <cuda/functional> // cuda::maximum, cuda::minimum
#include <cuda/std/cstdint> // cuda::std::uint32_t
#include <cuda/std/functional> // cuda::std::plus
CUB_NAMESPACE_BEGIN
// TODO(bgruber): deprecate in C++17 with a note: "replace by decltype(cuda::std::not_fn(EqualityOp{}))"
template <typename EqualityOp>
struct InequalityWrapper
{
EqualityOp op;
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE InequalityWrapper(EqualityOp op)
: op(op)
{}
template <typename T, typename U>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE bool operator()(T&& t, U&& u)
{
return !op(_CUDA_VSTD::forward<T>(t), _CUDA_VSTD::forward<U>(u));
}
};
struct ArgMax
{
template <typename T, typename OffsetT>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePair<OffsetT, T>
operator()(const KeyValuePair<OffsetT, T>& a, const KeyValuePair<OffsetT, T>& b) const
{
// Mooch BUG (device reduce argmax gk110 3.2 million random fp32)
// return ((b.value > a.value) ||
// ((a.value == b.value) && (b.key < a.key)))
// ? b : a;
if ((b.value > a.value) || ((a.value == b.value) && (b.key < a.key)))
{
return b;
}
return a;
}
};
struct ArgMin
{
template <typename T, typename OffsetT>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePair<OffsetT, T>
operator()(const KeyValuePair<OffsetT, T>& a, const KeyValuePair<OffsetT, T>& b) const
{
// Mooch BUG (device reduce argmax gk110 3.2 million random fp32)
// return ((b.value < a.value) ||
// ((a.value == b.value) && (b.key < a.key)))
// ? b : a;
if ((b.value < a.value) || ((a.value == b.value) && (b.key < a.key)))
{
return b;
}
return a;
}
};
namespace detail
{
template <typename ScanOpT>
struct ScanBySegmentOp
{
ScanOpT op;
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE ScanBySegmentOp() {}
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE ScanBySegmentOp(ScanOpT op)
: op(op)
{}
template <typename KeyValuePairT>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePairT operator()(const KeyValuePairT& first, const KeyValuePairT& second)
{
KeyValuePairT retval;
retval.key = first.key | second.key;
#ifdef _NVHPC_CUDA // WAR bug on nvc++
if (second.key)
{
retval.value = second.value;
}
else
{
// If second.value isn't copied into a temporary here, nvc++ will
// crash while compiling the TestScanByKeyWithLargeTypes test in
// thrust/testing/scan_by_key.cu:
auto v2 = second.value;
retval.value = op(first.value, v2);
}
#else // not nvc++:
// if (second.key) {
// The second partial reduction spans a segment reset, so it's value
// aggregate becomes the running aggregate
// else {
// The second partial reduction does not span a reset, so accumulate both
// into the running aggregate
// }
retval.value = (second.key) ? second.value : op(first.value, second.value);
#endif
return retval;
}
};
template <class OpT>
struct basic_binary_op_t
{
static constexpr bool value = false;
};
template <typename T>
struct basic_binary_op_t<_CUDA_VSTD::plus<T>>
{
static constexpr bool value = true;
};
template <typename T>
struct basic_binary_op_t<::cuda::minimum<T>>
{
static constexpr bool value = true;
};
template <typename T>
struct basic_binary_op_t<::cuda::maximum<T>>
{
static constexpr bool value = true;
};
} // namespace detail
template <typename B>
struct CastOp
{
template <typename A>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE B operator()(A&& a) const
{
return (B) a;
}
};
template <typename ScanOp>
class SwizzleScanOp
{
private:
ScanOp scan_op;
public:
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE SwizzleScanOp(ScanOp scan_op)
: scan_op(scan_op)
{}
template <typename T>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE T operator()(const T& a, const T& b)
{
T _a(a);
T _b(b);
return scan_op(_b, _a);
}
};
template <typename ReductionOpT>
struct ReduceBySegmentOp
{
ReductionOpT op;
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceBySegmentOp() {}
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceBySegmentOp(ReductionOpT op)
: op(op)
{}
template <typename KeyValuePairT>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePairT operator()(const KeyValuePairT& first, const KeyValuePairT& second)
{
KeyValuePairT retval;
retval.key = first.key + second.key;
#ifdef _NVHPC_CUDA // WAR bug on nvc++
if (second.key)
{
retval.value = second.value;
}
else
{
// If second.value isn't copied into a temporary here, nvc++ will
// crash while compiling the TestScanByKeyWithLargeTypes test in
// thrust/testing/scan_by_key.cu:
auto v2 = second.value;
retval.value = op(first.value, v2);
}
#else // not nvc++:
// if (second.key) {
// The second partial reduction spans a segment reset, so it's value
// aggregate becomes the running aggregate
// else {
// The second partial reduction does not span a reset, so accumulate both
// into the running aggregate
// }
retval.value = (second.key) ? second.value : op(first.value, second.value);
#endif
return retval;
}
};
template <typename ReductionOpT>
struct ReduceByKeyOp
{
ReductionOpT op;
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceByKeyOp() {}
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceByKeyOp(ReductionOpT op)
: op(op)
{}
template <typename KeyValuePairT>
_CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePairT operator()(const KeyValuePairT& first, const KeyValuePairT& second)
{
KeyValuePairT retval = second;
if (first.key == second.key)
{
retval.value = op(first.value, retval.value);
}
return retval;
}
};
#ifndef _CCCL_DOXYGEN_INVOKED // Do not document
//----------------------------------------------------------------------------------------------------------------------
// Predefined operators
namespace detail
{
template <typename ReductionOp, typename T>
inline constexpr bool is_cuda_std_min_max_v =
cub::detail::is_one_of_v<ReductionOp, //
::cuda::minimum<>,
::cuda::minimum<T>,
::cuda::maximum<>,
::cuda::maximum<T>>;
template <typename ReductionOp, typename T>
inline constexpr bool is_cuda_std_plus_mul_v =
cub::detail::is_one_of_v<ReductionOp, //
_CUDA_VSTD::plus<>,
_CUDA_VSTD::plus<T>,
_CUDA_VSTD::multiplies<>,
_CUDA_VSTD::multiplies<T>>;
template <typename ReductionOp, typename T>
inline constexpr bool is_cuda_std_bitwise_v =
cub::detail::is_one_of_v<ReductionOp,
_CUDA_VSTD::bit_and<>,
_CUDA_VSTD::bit_and<T>,
_CUDA_VSTD::bit_or<>,
_CUDA_VSTD::bit_or<T>,
_CUDA_VSTD::bit_xor<>,
_CUDA_VSTD::bit_xor<T>>;
template <typename ReductionOp, typename T>
inline constexpr bool is_cuda_std_operator_v =
is_cuda_std_min_max_v<ReductionOp, T> || //
is_cuda_std_plus_mul_v<ReductionOp, T> || //
is_cuda_std_bitwise_v<ReductionOp, T>;
} // namespace detail
#endif // !_CCCL_DOXYGEN_INVOKED
CUB_NAMESPACE_END