/usr/include/thrust/gather.h is in libthrust-dev 1.7.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 | /*
* Copyright 2008-2012 NVIDIA Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*! \file gather.h
* \brief Irregular copying from a source range
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/execution_policy.h>
namespace thrust
{
/*! \addtogroup gathering
* \ingroup copying
* \{
*/
/*! \p gather 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>, the
* value <tt>input_first[\*i]</tt> is assigned to <tt>*(result + (i - map_first))</tt>.
* \p RandomAccessIterator must permit random access.
*
* The algorithm's execution is parallelized as determined by \p exec.
*
* \param exec The execution policy to use for parallelization.
* \param map_first Beginning of the range of gather locations.
* \param map_last End of the range of gather locations.
* \param input_first Beginning of the source range.
* \param result Beginning of the destination range.
*
* \tparam DerivedPolicy The name of the derived execution policy.
* \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.
* \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>.
*
* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
*
* \remark \p gather is the inverse of thrust::scatter.
*
* The following code snippet demonstrates how to use \p gather to reorder
* a range using the \p thrust::device execution policy for parallelization:
*
* \code
* #include <thrust/gather.h>
* #include <thrust/device_vector.h>
* #include <thrust/execution_policy.h>
* ...
* // mark even indices with a 1; odd indices with a 0
* int values[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
* thrust::device_vector<int> d_values(values, values + 10);
*
* // gather 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);
* thrust::gather(thrust::device,
* d_map.begin(), d_map.end(),
* d_values.begin(),
* d_output.begin());
* // d_output is now {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
* \endcode
*/
template<typename DerivedPolicy,
typename InputIterator,
typename RandomAccessIterator,
typename OutputIterator>
OutputIterator gather(const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
InputIterator map_first,
InputIterator map_last,
RandomAccessIterator input_first,
OutputIterator result);
/*! \p gather 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>, 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 input_first Beginning of the source range.
* \param result Beginning of the destination range.
*
* \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.
* \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>.
*
* \pre The range <tt>[map_first, map_last)</tt> shall not overlap the range <tt>[result, result + (map_last - map_first))</tt>.
*
* \remark \p gather is the inverse of thrust::scatter.
*
* The following code snippet demonstrates how to use \p gather to reorder
* a range.
*
* \code
* #include <thrust/gather.h>
* #include <thrust/device_vector.h>
* ...
* // mark even indices with a 1; odd indices with a 0
* int values[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
* thrust::device_vector<int> d_values(values, values + 10);
*
* // gather 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);
* thrust::gather(d_map.begin(), d_map.end(),
* d_values.begin(),
* d_output.begin());
* // d_output is now {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
* \endcode
*/
template<typename InputIterator,
typename RandomAccessIterator,
typename OutputIterator>
OutputIterator gather(InputIterator map_first,
InputIterator map_last,
RandomAccessIterator input_first,
OutputIterator result);
/*! \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>\*(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.
*
* The algorithm's execution is parallelized as determined by \p exec.
*
* \param exec The execution policy to use for parallelization.
* \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.
*
* \tparam DerivedPolicy The name of the derived execution policy.
* \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 bool.
* \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>.
*
* \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 using the \p thrust::device execution policy:
*
* \code
* #include <thrust/gather.h>
* #include <thrust/device_vector.h>
* #include <thrust/execution_policy.h>
* ...
*
* int values[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
* thrust::device_vector<int> d_values(values, values + 10);
*
* // select elements at even-indexed locations
* int stencil[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
* 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());
* // 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>
OutputIterator gather_if(const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
InputIterator1 map_first,
InputIterator1 map_last,
InputIterator2 stencil,
RandomAccessIterator input_first,
OutputIterator result);
/*! \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>\*(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.
*
* \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 bool.
* \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>.
*
* \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.
*
* \code
* #include <thrust/gather.h>
* #include <thrust/device_vector.h>
* ...
*
* int values[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
* thrust::device_vector<int> d_values(values, values + 10);
*
* // select elements at even-indexed locations
* int stencil[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
* 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());
* // d_output is now {0, 7, 4, 7, 8, 7, 3, 7, 7, 7}
* \endcode
*/
template<typename InputIterator1,
typename InputIterator2,
typename RandomAccessIterator,
typename OutputIterator>
OutputIterator gather_if(InputIterator1 map_first,
InputIterator1 map_last,
InputIterator2 stencil,
RandomAccessIterator input_first,
OutputIterator result);
/*! \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.
*
* The algorithm's execution is parallelized as determined by \p exec.
*
* \param exec The execution policy to use for parallelization.
* \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 DerivedPolicy The name of the derived execution policy.
* \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 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>
|