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tools/cub-1.8.0/cub/device/device_select.cuh
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/****************************************************************************** * 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 * cub::DeviceSelect provides device-wide, parallel operations for compacting selected items from sequences of data items residing within device-accessible memory. */ #pragma once #include <stdio.h> #include <iterator> #include "dispatch/dispatch_select_if.cuh" #include "../util_namespace.cuh" /// Optional outer namespace(s) CUB_NS_PREFIX /// CUB namespace namespace cub { /** * \brief DeviceSelect provides device-wide, parallel operations for compacting selected items from sequences of data items residing within device-accessible memory. ![](select_logo.png) * \ingroup SingleModule * * \par Overview * These operations apply a selection criterion to selectively copy * items from a specified input sequence to a compact output sequence. * * \par Usage Considerations * \cdp_class{DeviceSelect} * * \par Performance * \linear_performance{select-flagged, select-if, and select-unique} * * \par * The following chart illustrates DeviceSelect::If * performance across different CUDA architectures for \p int32 items, * where 50% of the items are randomly selected. * * \image html select_if_int32_50_percent.png * * \par * The following chart illustrates DeviceSelect::Unique * performance across different CUDA architectures for \p int32 items * where segments have lengths uniformly sampled from [1,1000]. * * \image html select_unique_int32_len_500.png * * \par * \plots_below * */ struct DeviceSelect { /** * \brief Uses the \p d_flags sequence to selectively copy the corresponding items from \p d_in into \p d_out. The total number of items selected is written to \p d_num_selected_out. ![](select_flags_logo.png) * * \par * - The value type of \p d_flags must be castable to \p bool (e.g., \p bool, \p char, \p int, etc.). * - Copies of the selected items are compacted into \p d_out and maintain their original relative ordering. * - \devicestorage * * \par Snippet * The code snippet below illustrates the compaction of items selected from an \p int device vector. * \par * \code * #include <cub/cub.cuh> // or equivalently <cub/device/device_select.cuh> * * // Declare, allocate, and initialize device-accessible pointers for input, flags, and output * int num_items; // e.g., 8 * int *d_in; // e.g., [1, 2, 3, 4, 5, 6, 7, 8] * char *d_flags; // e.g., [1, 0, 0, 1, 0, 1, 1, 0] * int *d_out; // e.g., [ , , , , , , , ] * int *d_num_selected_out; // e.g., [ ] * ... * * // Determine temporary device storage requirements * void *d_temp_storage = NULL; * size_t temp_storage_bytes = 0; * cub::DeviceSelect::Flagged(d_temp_storage, temp_storage_bytes, d_in, d_flags, d_out, d_num_selected_out, num_items); * * // Allocate temporary storage * cudaMalloc(&d_temp_storage, temp_storage_bytes); * * // Run selection * cub::DeviceSelect::Flagged(d_temp_storage, temp_storage_bytes, d_in, d_flags, d_out, d_num_selected_out, num_items); * * // d_out <-- [1, 4, 6, 7] * // d_num_selected_out <-- [4] * * \endcode * * \tparam InputIteratorT <b>[inferred]</b> Random-access input iterator type for reading input items \iterator * \tparam FlagIterator <b>[inferred]</b> Random-access input iterator type for reading selection flags \iterator * \tparam OutputIteratorT <b>[inferred]</b> Random-access output iterator type for writing selected items \iterator * \tparam NumSelectedIteratorT <b>[inferred]</b> Output iterator type for recording the number of items selected \iterator */ template < typename InputIteratorT, typename FlagIterator, typename OutputIteratorT, typename NumSelectedIteratorT> CUB_RUNTIME_FUNCTION __forceinline__ static cudaError_t Flagged( void* d_temp_storage, ///< [in] %Device-accessible allocation of temporary storage. When NULL, the required allocation size is written to \p temp_storage_bytes and no work is done. size_t &temp_storage_bytes, ///< [in,out] Reference to size in bytes of \p d_temp_storage allocation InputIteratorT d_in, ///< [in] Pointer to the input sequence of data items FlagIterator d_flags, ///< [in] Pointer to the input sequence of selection flags OutputIteratorT d_out, ///< [out] Pointer to the output sequence of selected data items NumSelectedIteratorT d_num_selected_out, ///< [out] Pointer to the output total number of items selected (i.e., length of \p d_out) int num_items, ///< [in] Total number of input items (i.e., length of \p d_in) cudaStream_t stream = 0, ///< [in] <b>[optional]</b> CUDA stream to launch kernels within. Default is stream<sub>0</sub>. bool debug_synchronous = false) ///< [in] <b>[optional]</b> Whether or not to synchronize the stream after every kernel launch to check for errors. May cause significant slowdown. Default is \p false. { typedef int OffsetT; // Signed integer type for global offsets typedef NullType SelectOp; // Selection op (not used) typedef NullType EqualityOp; // Equality operator (not used) return DispatchSelectIf<InputIteratorT, FlagIterator, OutputIteratorT, NumSelectedIteratorT, SelectOp, EqualityOp, OffsetT, false>::Dispatch( d_temp_storage, temp_storage_bytes, d_in, d_flags, d_out, d_num_selected_out, SelectOp(), EqualityOp(), num_items, stream, debug_synchronous); } /** * \brief Uses the \p select_op functor to selectively copy items from \p d_in into \p d_out. The total number of items selected is written to \p d_num_selected_out. ![](select_logo.png) * * \par * - Copies of the selected items are compacted into \p d_out and maintain their original relative ordering. * - \devicestorage * * \par Performance * The following charts illustrate saturated select-if performance across different * CUDA architectures for \p int32 and \p int64 items, respectively. Items are * selected with 50% probability. * * \image html select_if_int32_50_percent.png * \image html select_if_int64_50_percent.png * * \par * The following charts are similar, but 5% selection probability: * * \image html select_if_int32_5_percent.png * \image html select_if_int64_5_percent.png * * \par Snippet * The code snippet below illustrates the compaction of items selected from an \p int device vector. * \par * \code * #include <cub/cub.cuh> // or equivalently <cub/device/device_select.cuh> * * // Functor type for selecting values less than some criteria * struct LessThan * { * int compare; * * CUB_RUNTIME_FUNCTION __forceinline__ * LessThan(int compare) : compare(compare) {} * * CUB_RUNTIME_FUNCTION __forceinline__ * bool operator()(const int &a) const { * return (a < compare); * } * }; * * // Declare, allocate, and initialize device-accessible pointers for input and output * int num_items; // e.g., 8 * int *d_in; // e.g., [0, 2, 3, 9, 5, 2, 81, 8] * int *d_out; // e.g., [ , , , , , , , ] * int *d_num_selected_out; // e.g., [ ] * LessThan select_op(7); * ... * * // Determine temporary device storage requirements * void *d_temp_storage = NULL; * size_t temp_storage_bytes = 0; * cub::DeviceSelect::If(d_temp_storage, temp_storage_bytes, d_in, d_out, d_num_selected_out, num_items, select_op); * * // Allocate temporary storage * cudaMalloc(&d_temp_storage, temp_storage_bytes); * * // Run selection * cub::DeviceSelect::If(d_temp_storage, temp_storage_bytes, d_in, d_out, d_num_selected_out, num_items, select_op); * * // d_out <-- [0, 2, 3, 5, 2] * // d_num_selected_out <-- [5] * * \endcode * * \tparam InputIteratorT <b>[inferred]</b> Random-access input iterator type for reading input items \iterator * \tparam OutputIteratorT <b>[inferred]</b> Random-access output iterator type for writing selected items \iterator * \tparam NumSelectedIteratorT <b>[inferred]</b> Output iterator type for recording the number of items selected \iterator * \tparam SelectOp <b>[inferred]</b> Selection operator type having member <tt>bool operator()(const T &a)</tt> */ template < typename InputIteratorT, typename OutputIteratorT, typename NumSelectedIteratorT, typename SelectOp> CUB_RUNTIME_FUNCTION __forceinline__ static cudaError_t If( void* d_temp_storage, ///< [in] %Device-accessible allocation of temporary storage. When NULL, the required allocation size is written to \p temp_storage_bytes and no work is done. size_t &temp_storage_bytes, ///< [in,out] Reference to size in bytes of \p d_temp_storage allocation InputIteratorT d_in, ///< [in] Pointer to the input sequence of data items OutputIteratorT d_out, ///< [out] Pointer to the output sequence of selected data items NumSelectedIteratorT d_num_selected_out, ///< [out] Pointer to the output total number of items selected (i.e., length of \p d_out) int num_items, ///< [in] Total number of input items (i.e., length of \p d_in) SelectOp select_op, ///< [in] Unary selection operator cudaStream_t stream = 0, ///< [in] <b>[optional]</b> CUDA stream to launch kernels within. Default is stream<sub>0</sub>. bool debug_synchronous = false) ///< [in] <b>[optional]</b> Whether or not to synchronize the stream after every kernel launch to check for errors. May cause significant slowdown. Default is \p false. { typedef int OffsetT; // Signed integer type for global offsets typedef NullType* FlagIterator; // FlagT iterator type (not used) typedef NullType EqualityOp; // Equality operator (not used) return DispatchSelectIf<InputIteratorT, FlagIterator, OutputIteratorT, NumSelectedIteratorT, SelectOp, EqualityOp, OffsetT, false>::Dispatch( d_temp_storage, temp_storage_bytes, d_in, NULL, d_out, d_num_selected_out, select_op, EqualityOp(), num_items, stream, debug_synchronous); } /** * \brief Given an input sequence \p d_in having runs of consecutive equal-valued keys, only the first key from each run is selectively copied to \p d_out. The total number of items selected is written to \p d_num_selected_out. ![](unique_logo.png) * * \par * - The <tt>==</tt> equality operator is used to determine whether keys are equivalent * - Copies of the selected items are compacted into \p d_out and maintain their original relative ordering. * - \devicestorage * * \par Performance * The following charts illustrate saturated select-unique performance across different * CUDA architectures for \p int32 and \p int64 items, respectively. Segments have * lengths uniformly sampled from [1,1000]. * * \image html select_unique_int32_len_500.png * \image html select_unique_int64_len_500.png * * \par * The following charts are similar, but with segment lengths uniformly sampled from [1,10]: * * \image html select_unique_int32_len_5.png * \image html select_unique_int64_len_5.png * * \par Snippet * The code snippet below illustrates the compaction of items selected from an \p int device vector. * \par * \code * #include <cub/cub.cuh> // or equivalently <cub/device/device_select.cuh> * * // Declare, allocate, and initialize device-accessible pointers for input and output * int num_items; // e.g., 8 * int *d_in; // e.g., [0, 2, 2, 9, 5, 5, 5, 8] * int *d_out; // e.g., [ , , , , , , , ] * int *d_num_selected_out; // e.g., [ ] * ... * * // Determine temporary device storage requirements * void *d_temp_storage = NULL; * size_t temp_storage_bytes = 0; * cub::DeviceSelect::Unique(d_temp_storage, temp_storage_bytes, d_in, d_out, d_num_selected_out, num_items); * * // Allocate temporary storage * cudaMalloc(&d_temp_storage, temp_storage_bytes); * * // Run selection * cub::DeviceSelect::Unique(d_temp_storage, temp_storage_bytes, d_in, d_out, d_num_selected_out, num_items); * * // d_out <-- [0, 2, 9, 5, 8] * // d_num_selected_out <-- [5] * * \endcode * * \tparam InputIteratorT <b>[inferred]</b> Random-access input iterator type for reading input items \iterator * \tparam OutputIteratorT <b>[inferred]</b> Random-access output iterator type for writing selected items \iterator * \tparam NumSelectedIteratorT <b>[inferred]</b> Output iterator type for recording the number of items selected \iterator */ template < typename InputIteratorT, typename OutputIteratorT, typename NumSelectedIteratorT> CUB_RUNTIME_FUNCTION __forceinline__ static cudaError_t Unique( void* d_temp_storage, ///< [in] %Device-accessible allocation of temporary storage. When NULL, the required allocation size is written to \p temp_storage_bytes and no work is done. size_t &temp_storage_bytes, ///< [in,out] Reference to size in bytes of \p d_temp_storage allocation InputIteratorT d_in, ///< [in] Pointer to the input sequence of data items OutputIteratorT d_out, ///< [out] Pointer to the output sequence of selected data items NumSelectedIteratorT d_num_selected_out, ///< [out] Pointer to the output total number of items selected (i.e., length of \p d_out) int num_items, ///< [in] Total number of input items (i.e., length of \p d_in) cudaStream_t stream = 0, ///< [in] <b>[optional]</b> CUDA stream to launch kernels within. Default is stream<sub>0</sub>. bool debug_synchronous = false) ///< [in] <b>[optional]</b> Whether or not to synchronize the stream after every kernel launch to check for errors. May cause significant slowdown. Default is \p false. { typedef int OffsetT; // Signed integer type for global offsets typedef NullType* FlagIterator; // FlagT iterator type (not used) typedef NullType SelectOp; // Selection op (not used) typedef Equality EqualityOp; // Default == operator return DispatchSelectIf<InputIteratorT, FlagIterator, OutputIteratorT, NumSelectedIteratorT, SelectOp, EqualityOp, OffsetT, false>::Dispatch( d_temp_storage, temp_storage_bytes, d_in, NULL, d_out, d_num_selected_out, SelectOp(), EqualityOp(), num_items, stream, debug_synchronous); } }; /** * \example example_device_select_flagged.cu * \example example_device_select_if.cu * \example example_device_select_unique.cu */ } // CUB namespace CUB_NS_POSTFIX // Optional outer namespace(s) |