diff options
Diffstat (limited to 'libstdc++-v3/include/parallel/equally_split.h')
| -rw-r--r-- | libstdc++-v3/include/parallel/equally_split.h | 99 |
1 files changed, 49 insertions, 50 deletions
diff --git a/libstdc++-v3/include/parallel/equally_split.h b/libstdc++-v3/include/parallel/equally_split.h index 31ed87d16f3..481c9886840 100644 --- a/libstdc++-v3/include/parallel/equally_split.h +++ b/libstdc++-v3/include/parallel/equally_split.h @@ -1,6 +1,6 @@ // -*- C++ -*- -// Copyright (C) 2007, 2009 Free Software Foundation, Inc. +// Copyright (C) 2007, 2008, 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 @@ -33,57 +33,56 @@ 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 _DifferenceType, typename _OutputIterator> - _OutputIterator - equally_split(_DifferenceType __n, _ThreadIndex __num_threads, - _OutputIterator __s) - { - _DifferenceType __chunk_length = __n / __num_threads; - _DifferenceType __num_longer_chunks = __n % __num_threads; - _DifferenceType __pos = 0; - for (_ThreadIndex __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. + * + * 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 _DifferenceType, typename _OutputIterator> + _OutputIterator + equally_split(_DifferenceType __n, _ThreadIndex __num_threads, + _OutputIterator __s) + { + _DifferenceType __chunk_length = __n / __num_threads; + _DifferenceType __num_longer_chunks = __n % __num_threads; + _DifferenceType __pos = 0; + for (_ThreadIndex __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 splitting point */ -template<typename _DifferenceType> - _DifferenceType - equally_split_point(_DifferenceType __n, - _ThreadIndex __num_threads, - _ThreadIndex __thread_no) - { - _DifferenceType __chunk_length = __n / __num_threads; - _DifferenceType __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) + /** @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 splitting point */ + template<typename _DifferenceType> + _DifferenceType + equally_split_point(_DifferenceType __n, + _ThreadIndex __num_threads, + _ThreadIndex __thread_no) + { + _DifferenceType __chunk_length = __n / __num_threads; + _DifferenceType __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 */ |