/******************************************************************************
* 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.
*
******************************************************************************/
/**
* \file
* The cub::BlockDiscontinuity class provides [collective](index.html#sec0) methods for flagging discontinuities within an ordered set of items partitioned across a CUDA thread block.
*/
#pragma once
#include "../config.cuh"
#include "../util_type.cuh"
#include "../util_ptx.cuh"
CUB_NAMESPACE_BEGIN
template <
typename T,
int BLOCK_DIM_X,
int BLOCK_DIM_Y = 1,
int BLOCK_DIM_Z = 1,
int PTX_ARCH = CUB_PTX_ARCH>
class BlockAdjacentDifference
{
private:
/******************************************************************************
* Constants and type definitions
******************************************************************************/
/// Constants
enum
{
/// The thread block size in threads
BLOCK_THREADS = BLOCK_DIM_X * BLOCK_DIM_Y * BLOCK_DIM_Z,
};
/// Shared memory storage layout type (last element from each thread's input)
struct _TempStorage
{
T first_items[BLOCK_THREADS];
T last_items[BLOCK_THREADS];
};
/******************************************************************************
* Utility methods
******************************************************************************/
/// Internal storage allocator
__device__ __forceinline__ _TempStorage& PrivateStorage()
{
__shared__ _TempStorage private_storage;
return private_storage;
}
/// Specialization for when FlagOp has third index param
template ::HAS_PARAM>
struct ApplyOp
{
// Apply flag operator
static __device__ __forceinline__ T FlagT(FlagOp flag_op, const T &a, const T &b, int idx)
{
return flag_op(b, a, idx);
}
};
/// Specialization for when FlagOp does not have a third index param
template
struct ApplyOp
{
// Apply flag operator
static __device__ __forceinline__ T FlagT(FlagOp flag_op, const T &a, const T &b, int /*idx*/)
{
return flag_op(b, a);
}
};
/// Templated unrolling of item comparison (inductive case)
template
struct Iterate
{
// Head flags
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
static __device__ __forceinline__ void FlagHeads(
int linear_tid,
FlagT (&flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
T (&preds)[ITEMS_PER_THREAD], ///< [out] Calling thread's predecessor items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
preds[ITERATION] = input[ITERATION - 1];
flags[ITERATION] = ApplyOp::FlagT(
flag_op,
preds[ITERATION],
input[ITERATION],
(linear_tid * ITEMS_PER_THREAD) + ITERATION);
Iterate::FlagHeads(linear_tid, flags, input, preds, flag_op);
}
// Tail flags
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
static __device__ __forceinline__ void FlagTails(
int linear_tid,
FlagT (&flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
flags[ITERATION] = ApplyOp::FlagT(
flag_op,
input[ITERATION],
input[ITERATION + 1],
(linear_tid * ITEMS_PER_THREAD) + ITERATION + 1);
Iterate::FlagTails(linear_tid, flags, input, flag_op);
}
};
/// Templated unrolling of item comparison (termination case)
template
struct Iterate
{
// Head flags
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
static __device__ __forceinline__ void FlagHeads(
int /*linear_tid*/,
FlagT (&/*flags*/)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&/*input*/)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
T (&/*preds*/)[ITEMS_PER_THREAD], ///< [out] Calling thread's predecessor items
FlagOp /*flag_op*/) ///< [in] Binary boolean flag predicate
{}
// Tail flags
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
static __device__ __forceinline__ void FlagTails(
int /*linear_tid*/,
FlagT (&/*flags*/)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&/*input*/)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp /*flag_op*/) ///< [in] Binary boolean flag predicate
{}
};
/******************************************************************************
* Thread fields
******************************************************************************/
/// Shared storage reference
_TempStorage &temp_storage;
/// Linear thread-id
unsigned int linear_tid;
public:
/// \smemstorage{BlockDiscontinuity}
struct TempStorage : Uninitialized<_TempStorage> {};
/******************************************************************//**
* \name Collective constructors
*********************************************************************/
//@{
/**
* \brief Collective constructor using a private static allocation of shared memory as temporary storage.
*/
__device__ __forceinline__ BlockAdjacentDifference()
:
temp_storage(PrivateStorage()),
linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
{}
/**
* \brief Collective constructor using the specified memory allocation as temporary storage.
*/
__device__ __forceinline__ BlockAdjacentDifference(
TempStorage &temp_storage) ///< [in] Reference to memory allocation having layout type TempStorage
:
temp_storage(temp_storage.Alias()),
linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
{}
//@} end member group
/******************************************************************//**
* \name Head flag operations
*********************************************************************/
//@{
#ifndef DOXYGEN_SHOULD_SKIP_THIS // Do not document
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeads(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
T (&preds)[ITEMS_PER_THREAD], ///< [out] Calling thread's predecessor items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
// Share last item
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
if (linear_tid == 0)
{
// Set flag for first thread-item (preds[0] is undefined)
head_flags[0] = 1;
}
else
{
preds[0] = temp_storage.last_items[linear_tid - 1];
head_flags[0] = ApplyOp::FlagT(flag_op, preds[0], input[0], linear_tid * ITEMS_PER_THREAD);
}
// Set head_flags for remaining items
Iterate<1, ITEMS_PER_THREAD>::FlagHeads(linear_tid, head_flags, input, preds, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeads(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
T (&preds)[ITEMS_PER_THREAD], ///< [out] Calling thread's predecessor items
FlagOp flag_op, ///< [in] Binary boolean flag predicate
T tile_predecessor_item) ///< [in] [thread0 only] Item with which to compare the first tile item (input0 from thread0).
{
// Share last item
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
// Set flag for first thread-item
preds[0] = (linear_tid == 0) ?
tile_predecessor_item : // First thread
temp_storage.last_items[linear_tid - 1];
head_flags[0] = ApplyOp::FlagT(flag_op, preds[0], input[0], linear_tid * ITEMS_PER_THREAD);
// Set head_flags for remaining items
Iterate<1, ITEMS_PER_THREAD>::FlagHeads(linear_tid, head_flags, input, preds, flag_op);
}
#endif // DOXYGEN_SHOULD_SKIP_THIS
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeads(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
T preds[ITEMS_PER_THREAD];
FlagHeads(head_flags, input, preds, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeads(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op, ///< [in] Binary boolean flag predicate
T tile_predecessor_item) ///< [in] [thread0 only] Item with which to compare the first tile item (input0 from thread0).
{
T preds[ITEMS_PER_THREAD];
FlagHeads(head_flags, input, preds, flag_op, tile_predecessor_item);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagTails(
FlagT (&tail_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity tail_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
// Share first item
temp_storage.first_items[linear_tid] = input[0];
CTA_SYNC();
// Set flag for last thread-item
tail_flags[ITEMS_PER_THREAD - 1] = (linear_tid == BLOCK_THREADS - 1) ?
1 : // Last thread
ApplyOp::FlagT(
flag_op,
input[ITEMS_PER_THREAD - 1],
temp_storage.first_items[linear_tid + 1],
(linear_tid * ITEMS_PER_THREAD) + ITEMS_PER_THREAD);
// Set tail_flags for remaining items
Iterate<0, ITEMS_PER_THREAD - 1>::FlagTails(linear_tid, tail_flags, input, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagTails(
FlagT (&tail_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity tail_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op, ///< [in] Binary boolean flag predicate
T tile_successor_item) ///< [in] [threadBLOCK_THREADS-1 only] Item with which to compare the last tile item (inputITEMS_PER_THREAD-1 from threadBLOCK_THREADS-1).
{
// 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];
tail_flags[ITEMS_PER_THREAD - 1] = ApplyOp::FlagT(
flag_op,
input[ITEMS_PER_THREAD - 1],
successor_item,
(linear_tid * ITEMS_PER_THREAD) + ITEMS_PER_THREAD);
// Set tail_flags for remaining items
Iterate<0, ITEMS_PER_THREAD - 1>::FlagTails(linear_tid, tail_flags, input, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeadsAndTails(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
FlagT (&tail_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity tail_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
// Share first and last items
temp_storage.first_items[linear_tid] = input[0];
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
T preds[ITEMS_PER_THREAD];
// Set flag for first thread-item
preds[0] = temp_storage.last_items[linear_tid - 1];
if (linear_tid == 0)
{
head_flags[0] = 1;
}
else
{
head_flags[0] = ApplyOp::FlagT(
flag_op,
preds[0],
input[0],
linear_tid * ITEMS_PER_THREAD);
}
// Set flag for last thread-item
tail_flags[ITEMS_PER_THREAD - 1] = (linear_tid == BLOCK_THREADS - 1) ?
1 : // Last thread
ApplyOp::FlagT(
flag_op,
input[ITEMS_PER_THREAD - 1],
temp_storage.first_items[linear_tid + 1],
(linear_tid * ITEMS_PER_THREAD) + ITEMS_PER_THREAD);
// Set head_flags for remaining items
Iterate<1, ITEMS_PER_THREAD>::FlagHeads(linear_tid, head_flags, input, preds, flag_op);
// Set tail_flags for remaining items
Iterate<0, ITEMS_PER_THREAD - 1>::FlagTails(linear_tid, tail_flags, input, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeadsAndTails(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
FlagT (&tail_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity tail_flags
T tile_successor_item, ///< [in] [threadBLOCK_THREADS-1 only] Item with which to compare the last tile item (inputITEMS_PER_THREAD-1 from threadBLOCK_THREADS-1).
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
// Share first and last items
temp_storage.first_items[linear_tid] = input[0];
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
T preds[ITEMS_PER_THREAD];
// Set flag for first thread-item
if (linear_tid == 0)
{
head_flags[0] = 1;
}
else
{
preds[0] = temp_storage.last_items[linear_tid - 1];
head_flags[0] = ApplyOp::FlagT(
flag_op,
preds[0],
input[0],
linear_tid * ITEMS_PER_THREAD);
}
// 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];
tail_flags[ITEMS_PER_THREAD - 1] = ApplyOp::FlagT(
flag_op,
input[ITEMS_PER_THREAD - 1],
successor_item,
(linear_tid * ITEMS_PER_THREAD) + ITEMS_PER_THREAD);
// Set head_flags for remaining items
Iterate<1, ITEMS_PER_THREAD>::FlagHeads(linear_tid, head_flags, input, preds, flag_op);
// Set tail_flags for remaining items
Iterate<0, ITEMS_PER_THREAD - 1>::FlagTails(linear_tid, tail_flags, input, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeadsAndTails(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T tile_predecessor_item, ///< [in] [thread0 only] Item with which to compare the first tile item (input0 from thread0).
FlagT (&tail_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity tail_flags
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
// Share first and last items
temp_storage.first_items[linear_tid] = input[0];
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
T preds[ITEMS_PER_THREAD];
// Set flag for first thread-item
preds[0] = (linear_tid == 0) ?
tile_predecessor_item : // First thread
temp_storage.last_items[linear_tid - 1];
head_flags[0] = ApplyOp::FlagT(
flag_op,
preds[0],
input[0],
linear_tid * ITEMS_PER_THREAD);
// Set flag for last thread-item
tail_flags[ITEMS_PER_THREAD - 1] = (linear_tid == BLOCK_THREADS - 1) ?
1 : // Last thread
ApplyOp::FlagT(
flag_op,
input[ITEMS_PER_THREAD - 1],
temp_storage.first_items[linear_tid + 1],
(linear_tid * ITEMS_PER_THREAD) + ITEMS_PER_THREAD);
// Set head_flags for remaining items
Iterate<1, ITEMS_PER_THREAD>::FlagHeads(linear_tid, head_flags, input, preds, flag_op);
// Set tail_flags for remaining items
Iterate<0, ITEMS_PER_THREAD - 1>::FlagTails(linear_tid, tail_flags, input, flag_op);
}
template <
int ITEMS_PER_THREAD,
typename FlagT,
typename FlagOp>
__device__ __forceinline__ void FlagHeadsAndTails(
FlagT (&head_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity head_flags
T tile_predecessor_item, ///< [in] [thread0 only] Item with which to compare the first tile item (input0 from thread0).
FlagT (&tail_flags)[ITEMS_PER_THREAD], ///< [out] Calling thread's discontinuity tail_flags
T tile_successor_item, ///< [in] [threadBLOCK_THREADS-1 only] Item with which to compare the last tile item (inputITEMS_PER_THREAD-1 from threadBLOCK_THREADS-1).
T (&input)[ITEMS_PER_THREAD], ///< [in] Calling thread's input items
FlagOp flag_op) ///< [in] Binary boolean flag predicate
{
// Share first and last items
temp_storage.first_items[linear_tid] = input[0];
temp_storage.last_items[linear_tid] = input[ITEMS_PER_THREAD - 1];
CTA_SYNC();
T preds[ITEMS_PER_THREAD];
// Set flag for first thread-item
preds[0] = (linear_tid == 0) ?
tile_predecessor_item : // First thread
temp_storage.last_items[linear_tid - 1];
head_flags[0] = ApplyOp::FlagT(
flag_op,
preds[0],
input[0],
linear_tid * ITEMS_PER_THREAD);
// 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];
tail_flags[ITEMS_PER_THREAD - 1] = ApplyOp::FlagT(
flag_op,
input[ITEMS_PER_THREAD - 1],
successor_item,
(linear_tid * ITEMS_PER_THREAD) + ITEMS_PER_THREAD);
// Set head_flags for remaining items
Iterate<1, ITEMS_PER_THREAD>::FlagHeads(linear_tid, head_flags, input, preds, flag_op);
// Set tail_flags for remaining items
Iterate<0, ITEMS_PER_THREAD - 1>::FlagTails(linear_tid, tail_flags, input, flag_op);
}
};
CUB_NAMESPACE_END