cub/block/block_adjacent_difference.cuh
File members: cub/block/block_adjacent_difference.cuh
/******************************************************************************
* Copyright (c) 2011, Duane Merrill. All rights reserved.
* Copyright (c) 2011-2021, NVIDIA CORPORATION. All rights reserved.
*
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* notice, this list of conditions and the following disclaimer.
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* documentation and/or other materials provided with the distribution.
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* 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 <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_ptx.cuh>
#include <cub/util_type.cuh>
CUB_NAMESPACE_BEGIN
template <typename T, int BLOCK_DIM_X, int BLOCK_DIM_Y = 1, int BLOCK_DIM_Z = 1, int LEGACY_PTX_ARCH = 0>
class BlockAdjacentDifference
{
private:
static constexpr int BLOCK_THREADS = BLOCK_DIM_X * BLOCK_DIM_Y * BLOCK_DIM_Z;
struct _TempStorage
{
T first_items[BLOCK_THREADS];
T last_items[BLOCK_THREADS];
};
_CCCL_DEVICE _CCCL_FORCEINLINE _TempStorage& PrivateStorage()
{
__shared__ _TempStorage private_storage;
return private_storage;
}
template <typename FlagOp, bool HAS_PARAM = BinaryOpHasIdxParam<T, FlagOp>::value>
struct ApplyOp
{
// Apply flag operator
static _CCCL_DEVICE _CCCL_FORCEINLINE T FlagT(FlagOp flag_op, const T& a, const T& b, int idx)
{
return flag_op(b, a, idx);
}
};
template <typename FlagOp>
struct ApplyOp<FlagOp, false>
{
// Apply flag operator
static _CCCL_DEVICE _CCCL_FORCEINLINE T FlagT(FlagOp flag_op, const T& a, const T& b, int /*idx*/)
{
return flag_op(b, a);
}
};
struct Iterate
{
template <int ITEMS_PER_THREAD, typename FlagT, typename FlagOp>
static _CCCL_DEVICE _CCCL_FORCEINLINE void FlagHeads(
int linear_tid,
FlagT (&flags)[ITEMS_PER_THREAD],
T (&input)[ITEMS_PER_THREAD],
T (&preds)[ITEMS_PER_THREAD],
FlagOp flag_op)
{
#pragma unroll
for (int i = 1; i < ITEMS_PER_THREAD; ++i)
{
preds[i] = input[i - 1];
flags[i] = ApplyOp<FlagOp>::FlagT(flag_op, preds[i], input[i], (linear_tid * ITEMS_PER_THREAD) + i);
}
}
template <int ITEMS_PER_THREAD, typename FlagT, typename FlagOp>
static _CCCL_DEVICE _CCCL_FORCEINLINE void
FlagTails(int linear_tid, FlagT (&flags)[ITEMS_PER_THREAD], T (&input)[ITEMS_PER_THREAD], FlagOp flag_op)
{
#pragma unroll
for (int i = 0; i < ITEMS_PER_THREAD - 1; ++i)
{
flags[i] = ApplyOp<FlagOp>::FlagT(flag_op, input[i], input[i + 1], (linear_tid * ITEMS_PER_THREAD) + i + 1);
}
}
};
_TempStorage& temp_storage;
unsigned int linear_tid;
public:
struct TempStorage : Uninitialized<_TempStorage>
{};
_CCCL_DEVICE _CCCL_FORCEINLINE BlockAdjacentDifference()
: temp_storage(PrivateStorage())
, linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
{}
_CCCL_DEVICE _CCCL_FORCEINLINE BlockAdjacentDifference(TempStorage& temp_storage)
: temp_storage(temp_storage.Alias())
, linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
{}
template <int ITEMS_PER_THREAD, typename OutputType, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void
SubtractLeft(T (&input)[ITEMS_PER_THREAD], OutputType (&output)[ITEMS_PER_THREAD], DifferenceOpT difference_op)
{
// Share last item
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
#pragma unroll
for (int item = ITEMS_PER_THREAD - 1; item > 0; item--)
{
output[item] = difference_op(input[item], input[item - 1]);
}
if (linear_tid == 0)
{
output[0] = input[0];
}
else
{
output[0] = difference_op(input[0], temp_storage.last_items[linear_tid - 1]);
}
}
template <int ITEMS_PER_THREAD, typename OutputT, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void SubtractLeft(
T (&input)[ITEMS_PER_THREAD],
OutputT (&output)[ITEMS_PER_THREAD],
DifferenceOpT difference_op,
T tile_predecessor_item)
{
// Share last item
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
#pragma unroll
for (int item = ITEMS_PER_THREAD - 1; item > 0; item--)
{
output[item] = difference_op(input[item], input[item - 1]);
}
// Set flag for first thread-item
if (linear_tid == 0)
{
output[0] = difference_op(input[0], tile_predecessor_item);
}
else
{
output[0] = difference_op(input[0], temp_storage.last_items[linear_tid - 1]);
}
}
template <int ITEMS_PER_THREAD, typename OutputType, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void SubtractLeftPartialTile(
T (&input)[ITEMS_PER_THREAD], OutputType (&output)[ITEMS_PER_THREAD], DifferenceOpT difference_op, int valid_items)
{
// Share last item
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
if ((linear_tid + 1) * ITEMS_PER_THREAD <= valid_items)
{
#pragma unroll
for (int item = ITEMS_PER_THREAD - 1; item > 0; item--)
{
output[item] = difference_op(input[item], input[item - 1]);
}
}
else
{
#pragma unroll
for (int item = ITEMS_PER_THREAD - 1; item > 0; item--)
{
const int idx = linear_tid * ITEMS_PER_THREAD + item;
if (idx < valid_items)
{
output[item] = difference_op(input[item], input[item - 1]);
}
else
{
output[item] = input[item];
}
}
}
if (linear_tid == 0 || valid_items <= linear_tid * ITEMS_PER_THREAD)
{
output[0] = input[0];
}
else
{
output[0] = difference_op(input[0], temp_storage.last_items[linear_tid - 1]);
}
}
template <int ITEMS_PER_THREAD, typename OutputType, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void SubtractLeftPartialTile(
T (&input)[ITEMS_PER_THREAD],
OutputType (&output)[ITEMS_PER_THREAD],
DifferenceOpT difference_op,
int valid_items,
T tile_predecessor_item)
{
// Share last item
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
if ((linear_tid + 1) * ITEMS_PER_THREAD <= valid_items)
{
#pragma unroll
for (int item = ITEMS_PER_THREAD - 1; item > 0; item--)
{
output[item] = difference_op(input[item], input[item - 1]);
}
}
else
{
#pragma unroll
for (int item = ITEMS_PER_THREAD - 1; item > 0; item--)
{
const int idx = linear_tid * ITEMS_PER_THREAD + item;
if (idx < valid_items)
{
output[item] = difference_op(input[item], input[item - 1]);
}
else
{
output[item] = input[item];
}
}
}
if (valid_items <= linear_tid * ITEMS_PER_THREAD)
{
output[0] = input[0];
}
else if (linear_tid == 0)
{
output[0] = difference_op(input[0], tile_predecessor_item);
}
else
{
output[0] = difference_op(input[0], temp_storage.last_items[linear_tid - 1]);
}
}
template <int ITEMS_PER_THREAD, typename OutputT, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void
SubtractRight(T (&input)[ITEMS_PER_THREAD], OutputT (&output)[ITEMS_PER_THREAD], DifferenceOpT difference_op)
{
// Share first item
temp_storage.first_items[linear_tid] = input[0];
CTA_SYNC();
#pragma unroll
for (int item = 0; item < ITEMS_PER_THREAD - 1; item++)
{
output[item] = difference_op(input[item], input[item + 1]);
}
if (linear_tid == BLOCK_THREADS - 1)
{
output[ITEMS_PER_THREAD - 1] = input[ITEMS_PER_THREAD - 1];
}
else
{
output[ITEMS_PER_THREAD - 1] =
difference_op(input[ITEMS_PER_THREAD - 1], temp_storage.first_items[linear_tid + 1]);
}
}
template <int ITEMS_PER_THREAD, typename OutputT, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void SubtractRight(
T (&input)[ITEMS_PER_THREAD],
OutputT (&output)[ITEMS_PER_THREAD],
DifferenceOpT difference_op,
T tile_successor_item)
{
// Share first item
temp_storage.first_items[linear_tid] = input[0];
CTA_SYNC();
// Set flag for last thread-item
T successor_item = (linear_tid == BLOCK_THREADS - 1)
? tile_successor_item // Last thread
: temp_storage.first_items[linear_tid + 1];
#pragma unroll
for (int item = 0; item < ITEMS_PER_THREAD - 1; item++)
{
output[item] = difference_op(input[item], input[item + 1]);
}
output[ITEMS_PER_THREAD - 1] = difference_op(input[ITEMS_PER_THREAD - 1], successor_item);
}
template <int ITEMS_PER_THREAD, typename OutputT, typename DifferenceOpT>
_CCCL_DEVICE _CCCL_FORCEINLINE void SubtractRightPartialTile(
T (&input)[ITEMS_PER_THREAD], OutputT (&output)[ITEMS_PER_THREAD], DifferenceOpT difference_op, int valid_items)
{
// Share first item
temp_storage.first_items[linear_tid] = input[0];
CTA_SYNC();
if ((linear_tid + 1) * ITEMS_PER_THREAD < valid_items)
{
#pragma unroll
for (int item = 0; item < ITEMS_PER_THREAD - 1; item++)
{
output[item] = difference_op(input[item], input[item + 1]);
}
output[ITEMS_PER_THREAD - 1] =
difference_op(input[ITEMS_PER_THREAD - 1], temp_storage.first_items[linear_tid + 1]);
}
else
{
#pragma unroll
for (int item = 0; item < ITEMS_PER_THREAD; item++)
{
const int idx = linear_tid * ITEMS_PER_THREAD + item;
// Right element of input[valid_items - 1] is out of bounds.
// According to the API it's copied into output array
// without modification.
if (idx < valid_items - 1)
{
output[item] = difference_op(input[item], input[item + 1]);
}
else
{
output[item] = input[item];
}
}
}
}
};
CUB_NAMESPACE_END