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439 lines
22 KiB
439 lines
22 KiB
11 years ago
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/*
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* Copyright 2008-2012 NVIDIA Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*! \file gather.h
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* \brief Irregular copying from a source range
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*/
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#pragma once
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#include <thrust/detail/config.h>
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#include <thrust/detail/execution_policy.h>
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namespace thrust
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{
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/*! \addtogroup gathering
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* \ingroup copying
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* \{
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*/
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/*! \p gather copies elements from a source array into a destination range according
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* to a map. For each input iterator \c i in the range <tt>[map_first, map_last)</tt>, the
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* value <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
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* \p RandomAccessIterator must permit random access.
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*
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* The algorithm's execution is parallelized as determined by \p exec.
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*
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* \param exec The execution policy to use for parallelization.
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* \param map_first Beginning of the range of gather locations.
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* \param map_last End of the range of gather locations.
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* \param input_first Beginning of the source range.
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* \param result Beginning of the destination range.
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*
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* \tparam DerivedPolicy The name of the derived execution policy.
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* \tparam InputIterator must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator's \c value_type must be convertible to \c RandomAccessIterator's \c difference_type.
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* \tparam RandomAccessIterator must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access Iterator</a> and \c RandomAccessIterator's \c value_type must be convertible to \c OutputIterator's \c value_type.
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* \tparam OutputIterator must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
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*
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* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
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*
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* \remark \p gather is the inverse of thrust::scatter.
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*
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* The following code snippet demonstrates how to use \p gather to reorder
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* a range using the \p thrust::device execution policy for parallelization:
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*
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* \code
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* #include <thrust/gather.h>
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* #include <thrust/device_vector.h>
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* #include <thrust/execution_policy.h>
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* ...
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* // mark even indices with a 1; odd indices with a 0
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* int values[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
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* thrust::device_vector<int> d_values(values, values + 10);
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*
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* // gather all even indices into the first half of the range
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* // and odd indices to the last half of the range
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* int map[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
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* thrust::device_vector<int> d_map(map, map + 10);
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*
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* thrust::device_vector<int> d_output(10);
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* thrust::gather(thrust::device,
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* d_map.begin(), d_map.end(),
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* d_values.begin(),
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* d_output.begin());
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* // d_output is now {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
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* \endcode
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*/
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template<typename DerivedPolicy,
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typename InputIterator,
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typename RandomAccessIterator,
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typename OutputIterator>
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OutputIterator gather(const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
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InputIterator map_first,
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InputIterator map_last,
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RandomAccessIterator input_first,
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OutputIterator result);
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/*! \p gather copies elements from a source array into a destination range according
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* to a map. For each input iterator \c i in the range <tt>[map_first, map_last)</tt>, the
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* value <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
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* \p RandomAccessIterator must permit random access.
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*
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* \param map_first Beginning of the range of gather locations.
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* \param map_last End of the range of gather locations.
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* \param input_first Beginning of the source range.
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* \param result Beginning of the destination range.
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*
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* \tparam InputIterator must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator's \c value_type must be convertible to \c RandomAccessIterator's \c difference_type.
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* \tparam RandomAccessIterator must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access Iterator</a> and \c RandomAccessIterator's \c value_type must be convertible to \c OutputIterator's \c value_type.
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* \tparam OutputIterator must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
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*
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* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
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*
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* \remark \p gather is the inverse of thrust::scatter.
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*
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* The following code snippet demonstrates how to use \p gather to reorder
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* a range.
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*
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* \code
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* #include <thrust/gather.h>
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* #include <thrust/device_vector.h>
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* ...
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* // mark even indices with a 1; odd indices with a 0
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* int values[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
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* thrust::device_vector<int> d_values(values, values + 10);
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*
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* // gather all even indices into the first half of the range
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* // and odd indices to the last half of the range
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* int map[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
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* thrust::device_vector<int> d_map(map, map + 10);
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*
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* thrust::device_vector<int> d_output(10);
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* thrust::gather(d_map.begin(), d_map.end(),
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* d_values.begin(),
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* d_output.begin());
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* // d_output is now {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
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* \endcode
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*/
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template<typename InputIterator,
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typename RandomAccessIterator,
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typename OutputIterator>
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OutputIterator gather(InputIterator map_first,
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InputIterator map_last,
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RandomAccessIterator input_first,
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OutputIterator result);
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/*! \p gather_if conditionally copies elements from a source array into a destination
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* range according to a map. For each input iterator \c i in the range <tt>[map_first, map_last)</tt>,
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* such that the value of <tt>\*(stencil + (i - map_first))</tt> is \c true, the value
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* <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
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* \p RandomAccessIterator must permit random access.
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*
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* The algorithm's execution is parallelized as determined by \p exec.
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*
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* \param exec The execution policy to use for parallelization.
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* \param map_first Beginning of the range of gather locations.
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* \param map_last End of the range of gather locations.
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* \param stencil Beginning of the range of predicate values.
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* \param input_first Beginning of the source range.
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* \param result Beginning of the destination range.
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*
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* \tparam DerivedPolicy The name of the derived execution policy.
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* \tparam InputIterator1 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator1's \c value_type must be convertible to \c RandomAccessIterator's \c difference_type.
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* \tparam InputIterator2 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator2's \c value_type must be convertible to \c bool.
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* \tparam RandomAccessIterator must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access iterator</a> and \c RandomAccessIterator's \c value_type must be convertible to \c OutputIterator's \c value_type.
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* \tparam OutputIterator must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
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*
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* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
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* \pre The range <tt>[stencil, stencil + (map_last - map_first))</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
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*
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* \remark \p gather_if is the inverse of \p scatter_if.
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*
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* The following code snippet demonstrates how to use \p gather_if to gather selected values from
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* an input range using the \p thrust::device execution policy:
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*
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* \code
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* #include <thrust/gather.h>
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* #include <thrust/device_vector.h>
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* #include <thrust/execution_policy.h>
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* ...
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*
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* int values[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
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* thrust::device_vector<int> d_values(values, values + 10);
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*
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* // select elements at even-indexed locations
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* int stencil[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
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* thrust::device_vector<int> d_stencil(stencil, stencil + 10);
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*
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* // map all even indices into the first half of the range
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* // and odd indices to the last half of the range
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* int map[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
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* thrust::device_vector<int> d_map(map, map + 10);
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*
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* thrust::device_vector<int> d_output(10, 7);
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* thrust::gather_if(thrust::device,
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* d_map.begin(), d_map.end(),
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* d_stencil.begin(),
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* d_values.begin(),
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* d_output.begin());
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* // d_output is now {0, 7, 4, 7, 8, 7, 3, 7, 7, 7}
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* \endcode
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*/
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template<typename DerivedPolicy,
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typename InputIterator1,
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typename InputIterator2,
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typename RandomAccessIterator,
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typename OutputIterator>
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OutputIterator gather_if(const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
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InputIterator1 map_first,
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InputIterator1 map_last,
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InputIterator2 stencil,
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RandomAccessIterator input_first,
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OutputIterator result);
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/*! \p gather_if conditionally copies elements from a source array into a destination
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* range according to a map. For each input iterator \c i in the range <tt>[map_first, map_last)</tt>,
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* such that the value of <tt>\*(stencil + (i - map_first))</tt> is \c true, the value
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* <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
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* \p RandomAccessIterator must permit random access.
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*
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* \param map_first Beginning of the range of gather locations.
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* \param map_last End of the range of gather locations.
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* \param stencil Beginning of the range of predicate values.
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* \param input_first Beginning of the source range.
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* \param result Beginning of the destination range.
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*
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* \tparam InputIterator1 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator1's \c value_type must be convertible to \c RandomAccessIterator's \c difference_type.
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* \tparam InputIterator2 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator2's \c value_type must be convertible to \c bool.
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* \tparam RandomAccessIterator must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access iterator</a> and \c RandomAccessIterator's \c value_type must be convertible to \c OutputIterator's \c value_type.
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* \tparam OutputIterator must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
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*
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* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
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* \pre The range <tt>[stencil, stencil + (map_last - map_first))</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
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*
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* \remark \p gather_if is the inverse of \p scatter_if.
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*
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* The following code snippet demonstrates how to use \p gather_if to gather selected values from
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* an input range.
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*
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* \code
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* #include <thrust/gather.h>
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* #include <thrust/device_vector.h>
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* ...
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*
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* int values[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
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* thrust::device_vector<int> d_values(values, values + 10);
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*
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* // select elements at even-indexed locations
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* int stencil[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
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* thrust::device_vector<int> d_stencil(stencil, stencil + 10);
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*
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* // map all even indices into the first half of the range
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* // and odd indices to the last half of the range
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* int map[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
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* thrust::device_vector<int> d_map(map, map + 10);
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*
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* thrust::device_vector<int> d_output(10, 7);
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* thrust::gather_if(d_map.begin(), d_map.end(),
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* d_stencil.begin(),
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* d_values.begin(),
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* d_output.begin());
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* // d_output is now {0, 7, 4, 7, 8, 7, 3, 7, 7, 7}
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* \endcode
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*/
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template<typename InputIterator1,
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typename InputIterator2,
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typename RandomAccessIterator,
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typename OutputIterator>
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OutputIterator gather_if(InputIterator1 map_first,
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InputIterator1 map_last,
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InputIterator2 stencil,
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RandomAccessIterator input_first,
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OutputIterator result);
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/*! \p gather_if conditionally copies elements from a source array into a destination
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* range according to a map. For each input iterator \c i in the range <tt>[map_first, map_last)</tt>
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* such that the value of <tt>pred(\*(stencil + (i - map_first)))</tt> is \c true,
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* the value <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
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* \p RandomAccessIterator must permit random access.
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*
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* The algorithm's execution is parallelized as determined by \p exec.
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*
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* \param exec The execution policy to use for parallelization.
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* \param map_first Beginning of the range of gather locations.
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* \param map_last End of the range of gather locations.
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* \param stencil Beginning of the range of predicate values.
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* \param input_first Beginning of the source range.
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* \param result Beginning of the destination range.
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* \param pred Predicate to apply to the stencil values.
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*
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* \tparam DerivedPolicy The name of the derived execution policy.
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* \tparam InputIterator1 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator1's \c value_type must be convertible to \c RandomAccessIterator's \c difference_type.
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* \tparam InputIterator2 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator2's \c value_type must be convertible to \c Predicate's \c argument_type.
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* \tparam RandomAccessIterator must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access iterator</a> and \c RandomAccessIterator's \c value_type must be convertible to \c OutputIterator's \c value_type.
|
||
|
|
* \tparam OutputIterator must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
|
||
|
|
* \tparam Predicate must be a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
|
||
|
|
*
|
||
|
|
* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
|
||
|
|
* \pre The range <tt>[stencil, stencil + (map_last - map_first))</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
|
||
|
|
*
|
||
|
|
* \remark \p gather_if is the inverse of \p scatter_if.
|
||
|
|
*
|
||
|
|
* The following code snippet demonstrates how to use \p gather_if to gather selected values from
|
||
|
|
* an input range based on an arbitrary selection function using the \p thrust::device execution policy for parallelization:
|
||
|
|
*
|
||
|
|
* \code
|
||
|
|
* #include <thrust/gather.h>
|
||
|
|
* #include <thrust/device_vector.h>
|
||
|
|
* #include <thrust/execution_policy.h>
|
||
|
|
*
|
||
|
|
* struct is_even
|
||
|
|
* {
|
||
|
|
* __host__ __device__
|
||
|
|
* bool operator()(const int x)
|
||
|
|
* {
|
||
|
|
* return (x % 2) == 0;
|
||
|
|
* }
|
||
|
|
* };
|
||
|
|
* ...
|
||
|
|
*
|
||
|
|
* int values[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
|
||
|
|
* thrust::device_vector<int> d_values(values, values + 10);
|
||
|
|
*
|
||
|
|
* // we will select an element when our stencil is even
|
||
|
|
* int stencil[10] = {0, 3, 4, 1, 4, 1, 2, 7, 8, 9};
|
||
|
|
* thrust::device_vector<int> d_stencil(stencil, stencil + 10);
|
||
|
|
*
|
||
|
|
* // map all even indices into the first half of the range
|
||
|
|
* // and odd indices to the last half of the range
|
||
|
|
* int map[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
|
||
|
|
* thrust::device_vector<int> d_map(map, map + 10);
|
||
|
|
*
|
||
|
|
* thrust::device_vector<int> d_output(10, 7);
|
||
|
|
* thrust::gather_if(thrust::device,
|
||
|
|
* d_map.begin(), d_map.end(),
|
||
|
|
* d_stencil.begin(),
|
||
|
|
* d_values.begin(),
|
||
|
|
* d_output.begin(),
|
||
|
|
* is_even());
|
||
|
|
* // d_output is now {0, 7, 4, 7, 8, 7, 3, 7, 7, 7}
|
||
|
|
* \endcode
|
||
|
|
*/
|
||
|
|
template<typename DerivedPolicy,
|
||
|
|
typename InputIterator1,
|
||
|
|
typename InputIterator2,
|
||
|
|
typename RandomAccessIterator,
|
||
|
|
typename OutputIterator,
|
||
|
|
typename Predicate>
|
||
|
|
OutputIterator gather_if(const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
|
||
|
|
InputIterator1 map_first,
|
||
|
|
InputIterator1 map_last,
|
||
|
|
InputIterator2 stencil,
|
||
|
|
RandomAccessIterator input_first,
|
||
|
|
OutputIterator result,
|
||
|
|
Predicate pred);
|
||
|
|
|
||
|
|
|
||
|
|
/*! \p gather_if conditionally copies elements from a source array into a destination
|
||
|
|
* range according to a map. For each input iterator \c i in the range <tt>[map_first, map_last)</tt>
|
||
|
|
* such that the value of <tt>pred(\*(stencil + (i - map_first)))</tt> is \c true,
|
||
|
|
* the value <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
|
||
|
|
* \p RandomAccessIterator must permit random access.
|
||
|
|
*
|
||
|
|
* \param map_first Beginning of the range of gather locations.
|
||
|
|
* \param map_last End of the range of gather locations.
|
||
|
|
* \param stencil Beginning of the range of predicate values.
|
||
|
|
* \param input_first Beginning of the source range.
|
||
|
|
* \param result Beginning of the destination range.
|
||
|
|
* \param pred Predicate to apply to the stencil values.
|
||
|
|
*
|
||
|
|
* \tparam InputIterator1 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator1's \c value_type must be convertible to \c RandomAccessIterator's \c difference_type.
|
||
|
|
* \tparam InputIterator2 must be a model of <a href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a> and \c InputIterator2's \c value_type must be convertible to \c Predicate's \c argument_type.
|
||
|
|
* \tparam RandomAccessIterator must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access iterator</a> and \c RandomAccessIterator's \c value_type must be convertible to \c OutputIterator's \c value_type.
|
||
|
|
* \tparam OutputIterator must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">Output Iterator</a>.
|
||
|
|
* \tparam Predicate must be a model of <a href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>.
|
||
|
|
*
|
||
|
|
* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
|
||
|
|
* \pre The range <tt>[stencil, stencil + (map_last - map_first))</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
|
||
|
|
*
|
||
|
|
* \remark \p gather_if is the inverse of \p scatter_if.
|
||
|
|
*
|
||
|
|
* The following code snippet demonstrates how to use \p gather_if to gather selected values from
|
||
|
|
* an input range based on an arbitrary selection function.
|
||
|
|
*
|
||
|
|
* \code
|
||
|
|
* #include <thrust/gather.h>
|
||
|
|
* #include <thrust/device_vector.h>
|
||
|
|
*
|
||
|
|
* struct is_even
|
||
|
|
* {
|
||
|
|
* __host__ __device__
|
||
|
|
* bool operator()(const int x)
|
||
|
|
* {
|
||
|
|
* return (x % 2) == 0;
|
||
|
|
* }
|
||
|
|
* };
|
||
|
|
* ...
|
||
|
|
*
|
||
|
|
* int values[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
|
||
|
|
* thrust::device_vector<int> d_values(values, values + 10);
|
||
|
|
*
|
||
|
|
* // we will select an element when our stencil is even
|
||
|
|
* int stencil[10] = {0, 3, 4, 1, 4, 1, 2, 7, 8, 9};
|
||
|
|
* thrust::device_vector<int> d_stencil(stencil, stencil + 10);
|
||
|
|
*
|
||
|
|
* // map all even indices into the first half of the range
|
||
|
|
* // and odd indices to the last half of the range
|
||
|
|
* int map[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
|
||
|
|
* thrust::device_vector<int> d_map(map, map + 10);
|
||
|
|
*
|
||
|
|
* thrust::device_vector<int> d_output(10, 7);
|
||
|
|
* thrust::gather_if(d_map.begin(), d_map.end(),
|
||
|
|
* d_stencil.begin(),
|
||
|
|
* d_values.begin(),
|
||
|
|
* d_output.begin(),
|
||
|
|
* is_even());
|
||
|
|
* // d_output is now {0, 7, 4, 7, 8, 7, 3, 7, 7, 7}
|
||
|
|
* \endcode
|
||
|
|
*/
|
||
|
|
template<typename InputIterator1,
|
||
|
|
typename InputIterator2,
|
||
|
|
typename RandomAccessIterator,
|
||
|
|
typename OutputIterator,
|
||
|
|
typename Predicate>
|
||
|
|
OutputIterator gather_if(InputIterator1 map_first,
|
||
|
|
InputIterator1 map_last,
|
||
|
|
InputIterator2 stencil,
|
||
|
|
RandomAccessIterator input_first,
|
||
|
|
OutputIterator result,
|
||
|
|
Predicate pred);
|
||
|
|
|
||
|
|
/*! \} // gathering
|
||
|
|
*/
|
||
|
|
|
||
|
|
} // end namespace thrust
|
||
|
|
|
||
|
|
#include <thrust/detail/gather.inl>
|
||
|
|
|