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Diffstat (limited to 'uclibc-crosstools-gcc-4.4.2-1/usr/mips-linux-uclibc/include/c++/4.4.2/parallel/equally_split.h')
-rw-r--r-- | uclibc-crosstools-gcc-4.4.2-1/usr/mips-linux-uclibc/include/c++/4.4.2/parallel/equally_split.h | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/uclibc-crosstools-gcc-4.4.2-1/usr/mips-linux-uclibc/include/c++/4.4.2/parallel/equally_split.h b/uclibc-crosstools-gcc-4.4.2-1/usr/mips-linux-uclibc/include/c++/4.4.2/parallel/equally_split.h new file mode 100644 index 0000000..ee4bfee --- /dev/null +++ b/uclibc-crosstools-gcc-4.4.2-1/usr/mips-linux-uclibc/include/c++/4.4.2/parallel/equally_split.h @@ -0,0 +1,87 @@ +// -*- C++ -*- + +// Copyright (C) 2007, 2009 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the terms +// of the GNU General Public License as published by the Free Software +// Foundation; either version 3, or (at your option) any later +// version. + +// This library is distributed in the hope that it will be useful, but +// WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// General Public License for more details. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +/** @file parallel/equally_split.h + * This file is a GNU parallel extension to the Standard C++ Library. + */ + +// Written by Johannes Singler. + +#ifndef _GLIBCXX_PARALLEL_EQUALLY_SPLIT_H +#define _GLIBCXX_PARALLEL_EQUALLY_SPLIT_H 1 + +namespace __gnu_parallel +{ +/** @brief Function to split a sequence into parts of almost equal size. + * + * The resulting sequence s of length num_threads+1 contains the splitting + * positions when splitting the range [0,n) into parts of almost + * equal size (plus minus 1). The first entry is 0, the last one + * n. There may result empty parts. + * @param n Number of elements + * @param num_threads Number of parts + * @param s Splitters + * @returns End of splitter sequence, i. e. @c s+num_threads+1 */ +template<typename difference_type, typename OutputIterator> + OutputIterator + equally_split(difference_type n, thread_index_t num_threads, OutputIterator s) + { + difference_type chunk_length = n / num_threads; + difference_type num_longer_chunks = n % num_threads; + difference_type pos = 0; + for (thread_index_t i = 0; i < num_threads; ++i) + { + *s++ = pos; + pos += (i < num_longer_chunks) ? (chunk_length + 1) : chunk_length; + } + *s++ = n; + return s; + } + + +/** @brief Function to split a sequence into parts of almost equal size. + * + * Returns the position of the splitting point between + * thread number thread_no (included) and + * thread number thread_no+1 (excluded). + * @param n Number of elements + * @param num_threads Number of parts + * @returns _SplittingAlgorithm point */ +template<typename difference_type> + difference_type + equally_split_point(difference_type n, + thread_index_t num_threads, + thread_index_t thread_no) + { + difference_type chunk_length = n / num_threads; + difference_type num_longer_chunks = n % num_threads; + if (thread_no < num_longer_chunks) + return thread_no * (chunk_length + 1); + else + return num_longer_chunks * (chunk_length + 1) + + (thread_no - num_longer_chunks) * chunk_length; + } +} + +#endif /* _GLIBCXX_PARALLEL_EQUALLY_SPLIT_H */ |