1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
/******************************************************************************
* Copyright (c) 2020, 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.
*
******************************************************************************/
/**
* \file
* Define helper math functions.
*/
#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 <type_traits>
CUB_NAMESPACE_BEGIN
namespace detail
{
template <typename T>
using is_integral_or_enum =
std::integral_constant<bool,
std::is_integral<T>::value || std::is_enum<T>::value>;
__host__ __device__ __forceinline__ constexpr std::size_t
VshmemSize(std::size_t max_shmem,
std::size_t shmem_per_block,
std::size_t num_blocks)
{
return shmem_per_block > max_shmem ? shmem_per_block * num_blocks : 0;
}
}
/**
* Divide n by d, round up if any remainder, and return the result.
*
* Effectively performs `(n + d - 1) / d`, but is robust against the case where
* `(n + d - 1)` would overflow.
*/
template <typename NumeratorT, typename DenominatorT>
__host__ __device__ __forceinline__ constexpr NumeratorT
DivideAndRoundUp(NumeratorT n, DenominatorT d)
{
static_assert(cub::detail::is_integral_or_enum<NumeratorT>::value &&
cub::detail::is_integral_or_enum<DenominatorT>::value,
"DivideAndRoundUp is only intended for integral types.");
// Static cast to undo integral promotion.
return static_cast<NumeratorT>(n / d + (n % d != 0 ? 1 : 0));
}
constexpr __device__ __host__ int
Nominal4BItemsToItemsCombined(int nominal_4b_items_per_thread, int combined_bytes)
{
return (cub::min)(nominal_4b_items_per_thread,
(cub::max)(1,
nominal_4b_items_per_thread * 8 /
combined_bytes));
}
template <typename T>
constexpr __device__ __host__ int
Nominal4BItemsToItems(int nominal_4b_items_per_thread)
{
return (cub::min)(nominal_4b_items_per_thread,
(cub::max)(1,
nominal_4b_items_per_thread * 4 /
static_cast<int>(sizeof(T))));
}
template <typename ItemT>
constexpr __device__ __host__ int
Nominal8BItemsToItems(int nominal_8b_items_per_thread)
{
return sizeof(ItemT) <= 8u
? nominal_8b_items_per_thread
: (cub::min)(nominal_8b_items_per_thread,
(cub::max)(1,
((nominal_8b_items_per_thread * 8) +
static_cast<int>(sizeof(ItemT)) - 1) /
static_cast<int>(sizeof(ItemT))));
}
/**
* \brief Computes the midpoint of the integers
*
* Extra operation is performed in order to prevent overflow.
*
* \return Half the sum of \p begin and \p end
*/
template <typename T>
constexpr __device__ __host__ T MidPoint(T begin, T end)
{
return begin + (end - begin) / 2;
}
CUB_NAMESPACE_END
|
