Classes¶

struct __accumulate_binop_reduct
General reduction, using a binary operator. struct __accumulate_selector
std::accumulate() selector. struct __adjacent_difference_selector
Selector that returns the difference between two adjacent __elements. struct __adjacent_find_selector
Test predicate on two adjacent elements. class __binder1st
Similar to std::binder1st, but giving the argument types explicitly. class __binder2nd
Similar to std::binder2nd, but giving the argument types explicitly. struct __count_if_selector
std::count_if () selector. struct __count_selector
std::count() selector. struct __fill_selector
std::fill() selector. struct __find_first_of_selector
Test predicate on several elements. struct __find_if_selector
Test predicate on a single element, used for std::find() and std::find_if (). struct __for_each_selector
std::for_each() selector. struct __generate_selector
std::generate() selector. struct __generic_find_selector
Base class of all __gnu_parallel::__find_template selectors. struct __generic_for_each_selector
Generic __selector for embarrassingly parallel functions. struct __identity_selector
Selector that just returns the passed iterator. struct __inner_product_selector
std::inner_product() selector. struct __max_element_reduct
Reduction for finding the maximum element, using a comparator. struct __min_element_reduct
Reduction for finding the maximum element, using a comparator. struct __mismatch_selector
Test inverted predicate on a single element. struct __multiway_merge_3_variant_sentinel_switch
Switch for 3-way merging with __sentinels turned off. struct __multiway_merge_3_variant_sentinel_switch< true, _RAIterIterator, _RAIter3, _DifferenceTp, _Compare >
Switch for 3-way merging with __sentinels turned on. struct __multiway_merge_4_variant_sentinel_switch
Switch for 4-way merging with __sentinels turned off. struct __multiway_merge_4_variant_sentinel_switch< true, _RAIterIterator, _RAIter3, _DifferenceTp, _Compare >
Switch for 4-way merging with __sentinels turned on. struct __multiway_merge_k_variant_sentinel_switch
Switch for k-way merging with __sentinels turned on. struct __multiway_merge_k_variant_sentinel_switch< false, __stable, _RAIterIterator, _RAIter3, _DifferenceTp, _Compare >
Switch for k-way merging with __sentinels turned off. struct __replace_if_selector
std::replace() selector. struct __replace_selector
std::replace() selector. struct __transform1_selector
std::transform() __selector, one input sequence variant. struct __transform2_selector
std::transform() __selector, two input sequences variant. class __unary_negate
Similar to std::unary_negate, but giving the argument types explicitly. struct _DRandomShufflingGlobalData
Data known to every thread participating in __gnu_parallel::__parallel_random_shuffle(). struct _DRSSorterPU
Local data for a thread participating in __gnu_parallel::__parallel_random_shuffle(). struct _DummyReduct
Reduction function doing nothing. class _EqualFromLess
Constructs predicate for equality from strict weak ordering predicate. struct _EqualTo
Similar to std::equal_to, but allows two different types. class _GuardedIterator
_Iterator wrapper supporting an implicit supremum at the end of the sequence, dominating all comparisons. class _IteratorPair
A pair of iterators. The usual iterator operations are applied to both child iterators. class _IteratorTriple
A triple of iterators. The usual iterator operations are applied to all three child iterators. struct _Job
One __job for a certain thread. struct _Less
Similar to std::less, but allows two different types. class _Lexicographic
Compare __a pair of types lexicographically, ascending. class _LexicographicReverse
Compare __a pair of types lexicographically, descending. class _LoserTree
Stable _LoserTree variant. class _LoserTree< false, _Tp, _Compare >
Unstable _LoserTree variant. class _LoserTreeBase
Guarded loser/tournament tree. class _LoserTreePointer
Stable _LoserTree implementation. class _LoserTreePointer< false, _Tp, _Compare >
Unstable _LoserTree implementation. class _LoserTreePointerBase
Base class of _Loser Tree implementation using pointers. class _LoserTreePointerUnguarded
Stable unguarded _LoserTree variant storing pointers. class _LoserTreePointerUnguarded< false, _Tp, _Compare >
Unstable unguarded _LoserTree variant storing pointers. class _LoserTreePointerUnguardedBase
Unguarded loser tree, keeping only pointers to the elements in the tree structure. struct _LoserTreeTraits
Traits for determining whether the loser tree should use pointers or copies. class _LoserTreeUnguarded
Stable implementation of unguarded _LoserTree. class _LoserTreeUnguarded< false, _Tp, _Compare >
Non-Stable implementation of unguarded _LoserTree. class _LoserTreeUnguardedBase
Base class for unguarded _LoserTree implementation. struct _Multiplies
Similar to std::multiplies, but allows two different types. struct _Nothing
Functor doing nothing. struct _Piece
Subsequence description. struct _Plus
Similar to std::plus, but allows two different types. struct _PMWMSSortingData
Data accessed by all threads. class _PseudoSequence
Sequence that conceptually consists of multiple copies of the same element. The copies are not stored explicitly, of course. class _PseudoSequenceIterator
_Iterator associated with __gnu_parallel::_PseudoSequence. If features the usual random-access iterator functionality. struct _QSBThreadLocal
Information local to one thread in the parallel quicksort run. class _RandomNumber
Random number generator, based on the Mersenne twister. class _RestrictedBoundedConcurrentQueue
Double-ended queue of bounded size, allowing lock-free atomic access. push_front() and pop_front() must not be called concurrently to each other, while pop_back() can be called concurrently at all times. empty(), size(), and top() are intentionally not provided. Calling them would not make sense in a concurrent setting. struct _SamplingSorter
Stable sorting functor. struct _SamplingSorter< false, _RAIter, _StrictWeakOrdering >
Non-__stable sorting functor. struct _Settings
class _Settings Run-time settings for the parallel mode including all tunable parameters. struct _SplitConsistently
Split consistently. struct _SplitConsistently< false, _RAIter, _Compare, _SortingPlacesIterator >
Split by sampling. struct _SplitConsistently< true, _RAIter, _Compare, _SortingPlacesIterator >
Split by exact splitting. struct balanced_quicksort_tag
Forces parallel sorting using balanced quicksort at compile time. struct balanced_tag
Recommends parallel execution using dynamic load-balancing at compile time. struct constant_size_blocks_tag
Selects the constant block size variant for std::find(). struct default_parallel_tag
Recommends parallel execution using the default parallel algorithm. struct equal_split_tag
Selects the equal splitting variant for std::find(). struct exact_tag
Forces parallel merging with exact splitting, at compile time. struct find_tag
Base class for for std::find() variants. struct growing_blocks_tag
Selects the growing block size variant for std::find(). struct multiway_mergesort_exact_tag
Forces parallel sorting using multiway mergesort with exact splitting at compile time. struct multiway_mergesort_sampling_tag
Forces parallel sorting using multiway mergesort with splitting by sampling at compile time. struct multiway_mergesort_tag
Forces parallel sorting using multiway mergesort at compile time. struct omp_loop_static_tag
Recommends parallel execution using OpenMP static load-balancing at compile time. struct omp_loop_tag
Recommends parallel execution using OpenMP dynamic load-balancing at compile time. struct parallel_tag
Recommends parallel execution at compile time, optionally using a user-specified number of threads. struct quicksort_tag
Forces parallel sorting using unbalanced quicksort at compile time. struct sampling_tag
Forces parallel merging with exact splitting, at compile time. struct sequential_tag
Forces sequential execution at compile time. struct unbalanced_tag
Recommends parallel execution using static load-balancing at compile time.

Typedefs¶

typedef unsigned short _BinIndex
Type to hold the index of a bin. typedef int64_t _CASable
Longest compare-and-swappable integer type on this platform. typedef uint64_t _SequenceIndex
Unsigned integer to index __elements. The total number of elements for each algorithm must fit into this type. typedef uint16_t _ThreadIndex
Unsigned integer to index a thread number. The maximum thread number (for each processor) must fit into this type.

Enumerations¶

enum _AlgorithmStrategy { heuristic, force_sequential, force_parallel }
Strategies for run-time algorithm selection: enum _FindAlgorithm { GROWING_BLOCKS, CONSTANT_SIZE_BLOCKS, EQUAL_SPLIT }
Find algorithms: enum _MultiwayMergeAlgorithm { LOSER_TREE }
Merging algorithms: enum _Parallelism { sequential, parallel_unbalanced, parallel_balanced, parallel_omp_loop, parallel_omp_loop_static, parallel_taskqueue }
Run-time equivalents for the compile-time tags. enum _PartialSumAlgorithm { RECURSIVE, LINEAR }
Partial sum algorithms: recursive, linear. enum _SortAlgorithm { MWMS, QS, QS_BALANCED }
Sorting algorithms: enum _SplittingAlgorithm { SAMPLING, EXACT }
Sorting/merging algorithms: sampling, __exact.

Functions¶

template<typename _Tp > _Tp __add_omp (volatile _Tp *__ptr, _Tp __addend)
template<typename _RAIter , typename _DifferenceTp > void __calc_borders (_RAIter __elements, _DifferenceTp __length, _DifferenceTp *__off)
Precalculate __advances for Knuth-Morris-Pratt algorithm. template<typename _Tp > bool __cas_omp (volatile _Tp *__ptr, _Tp __comparand, _Tp __replacement)
template<typename _Tp > bool __compare_and_swap (volatile _Tp *__ptr, _Tp __comparand, _Tp __replacement)
Compare-and-swap. template<typename _IIter , typename _OutputIterator > _OutputIterator __copy_tail (std::pair< _IIter, _IIter > __b, std::pair< _IIter, _IIter > __e, _OutputIterator __r)
void __decode2 (_CASable __x, int &__a, int &__b)
Decode two integers from one gnu_parallel::_CASable. template<typename _RAIter , typename _DifferenceTp > void __determine_samples (_PMWMSSortingData< _RAIter > *__sd, _DifferenceTp __num_samples)
Select _M_samples from a sequence. _CASable __encode2 (int __a, int __b)
Encode two integers into one gnu_parallel::_CASable. template<typename _DifferenceType , typename _OutputIterator > _OutputIterator __equally_split (_DifferenceType __n, _ThreadIndex __num_threads, _OutputIterator __s)
function to split a sequence into parts of almost equal size. template<typename _DifferenceType > _DifferenceType __equally_split_point (_DifferenceType __n, _ThreadIndex __num_threads, _ThreadIndex __thread_no)
function to split a sequence into parts of almost equal size. template<typename _Tp > _Tp __fetch_and_add (volatile _Tp *__ptr, _Tp __addend)
Add a value to a variable, atomically. template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector)
Parallel std::find, switch for different algorithms. template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector, constant_size_blocks_tag)
Parallel std::find, constant block size variant. template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector, equal_split_tag)
Parallel std::find, equal splitting variant. template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector, growing_blocks_tag)
Parallel std::find, growing block size variant. template<typename _IIter , typename _UserOp , typename _Functionality , typename _Red , typename _Result > _UserOp __for_each_template_random_access (_IIter __begin, _IIter __end, _UserOp __user_op, _Functionality &__functionality, _Red __reduction, _Result __reduction_start, _Result &__output, typename std::iterator_traits< _IIter >::difference_type __bound, _Parallelism __parallelism_tag)
Chose the desired algorithm by evaluating __parallelism_tag. template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __for_each_template_random_access_ed (_RAIter __begin, _RAIter __end, _Op __o, _Fu &__f, _Red __r, _Result __base, _Result &__output, typename std::iterator_traits< _RAIter >::difference_type __bound)
Embarrassingly parallel algorithm for random access iterators, using hand-crafted parallelization by equal splitting the work. template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __for_each_template_random_access_omp_loop (_RAIter __begin, _RAIter __end, _Op __o, _Fu &__f, _Red __r, _Result __base, _Result &__output, typename std::iterator_traits< _RAIter >::difference_type __bound)
Embarrassingly parallel algorithm for random access iterators, using an OpenMP for loop. template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __for_each_template_random_access_omp_loop_static (_RAIter __begin, _RAIter __end, _Op __o, _Fu &__f, _Red __r, _Result __base, _Result &__output, typename std::iterator_traits< _RAIter >::difference_type __bound)
Embarrassingly parallel algorithm for random access iterators, using an OpenMP for loop with static scheduling. template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __for_each_template_random_access_workstealing (_RAIter __begin, _RAIter __end, _Op __op, _Fu &__f, _Red __r, _Result __base, _Result &__output, typename std::iterator_traits< _RAIter >::difference_type __bound)
Work stealing algorithm for random access iterators. _ThreadIndex __get_max_threads ()
bool __is_parallel (const _Parallelism __p)
template<typename _IIter , typename _Compare > bool __is_sorted (_IIter __begin, _IIter __end, _Compare __comp)
Check whether [__begin, __end) is sorted according to __comp. template<typename _RAIter , typename _Compare > _RAIter __median_of_three_iterators (_RAIter __a, _RAIter __b, _RAIter __c, _Compare __comp)
Compute the median of three referenced elements, according to __comp. template<typename _RAIter1 , typename _RAIter2 , typename _OutputIterator , typename _DifferenceTp , typename _Compare > _OutputIterator __merge_advance (_RAIter1 &__begin1, _RAIter1 __end1, _RAIter2 &__begin2, _RAIter2 __end2, _OutputIterator __target, _DifferenceTp __max_length, _Compare __comp)
Merge routine being able to merge only the __max_length smallest elements. template<typename _RAIter1 , typename _RAIter2 , typename _OutputIterator , typename _DifferenceTp , typename _Compare > _OutputIterator __merge_advance_movc (_RAIter1 &__begin1, _RAIter1 __end1, _RAIter2 &__begin2, _RAIter2 __end2, _OutputIterator __target, _DifferenceTp __max_length, _Compare __comp)
Merge routine being able to merge only the __max_length smallest elements. template<typename _RAIter1 , typename _RAIter2 , typename _OutputIterator , typename _DifferenceTp , typename _Compare > _OutputIterator __merge_advance_usual (_RAIter1 &__begin1, _RAIter1 __end1, _RAIter2 &__begin2, _RAIter2 __end2, _OutputIterator __target, _DifferenceTp __max_length, _Compare __comp)
Merge routine being able to merge only the __max_length smallest elements. template<typename _RAIter1 , typename _RAIter3 , typename _Compare > _RAIter3 __parallel_merge_advance (_RAIter1 &__begin1, _RAIter1 __end1, _RAIter1 &__begin2, _RAIter1 __end2, _RAIter3 __target, typename std::iterator_traits< _RAIter1 >::difference_type __max_length, _Compare __comp)
Parallel merge routine being able to merge only the __max_length smallest elements. template<typename _RAIter1 , typename _RAIter2 , typename _RAIter3 , typename _Compare > _RAIter3 __parallel_merge_advance (_RAIter1 &__begin1, _RAIter1 __end1, _RAIter2 &__begin2, _RAIter2 __end2, _RAIter3 __target, typename std::iterator_traits< _RAIter1 >::difference_type __max_length, _Compare __comp)
Merge routine fallback to sequential in case the iterators of the two input sequences are of different type. template<typename _RAIter , typename _Compare > void __parallel_nth_element (_RAIter __begin, _RAIter __nth, _RAIter __end, _Compare __comp)
Parallel implementation of std::nth_element(). template<typename _RAIter , typename _Compare > void __parallel_partial_sort (_RAIter __begin, _RAIter __middle, _RAIter __end, _Compare __comp)
Parallel implementation of std::partial_sort(). template<typename _IIter , typename _OutputIterator , typename _BinaryOperation > _OutputIterator __parallel_partial_sum (_IIter __begin, _IIter __end, _OutputIterator __result, _BinaryOperation __bin_op)
Parallel partial sum front-__end. template<typename _IIter , typename _OutputIterator , typename _BinaryOperation > _OutputIterator __parallel_partial_sum_basecase (_IIter __begin, _IIter __end, _OutputIterator __result, _BinaryOperation __bin_op, typename std::iterator_traits< _IIter >::value_type __value)
Base case prefix sum routine. template<typename _IIter , typename _OutputIterator , typename _BinaryOperation > _OutputIterator __parallel_partial_sum_linear (_IIter __begin, _IIter __end, _OutputIterator __result, _BinaryOperation __bin_op, typename std::iterator_traits< _IIter >::difference_type __n)
Parallel partial sum implementation, two-phase approach, no recursion. template<typename _RAIter , typename _Predicate > std::iterator_traits< _RAIter >::difference_type __parallel_partition (_RAIter __begin, _RAIter __end, _Predicate __pred, _ThreadIndex __num_threads)
Parallel implementation of std::partition. template<typename _RAIter , typename _RandomNumberGenerator > void __parallel_random_shuffle (_RAIter __begin, _RAIter __end, _RandomNumberGenerator __rng=_RandomNumber())
Parallel random public call. template<typename _RAIter , typename _RandomNumberGenerator > void __parallel_random_shuffle_drs (_RAIter __begin, _RAIter __end, typename std::iterator_traits< _RAIter >::difference_type __n, _ThreadIndex __num_threads, _RandomNumberGenerator &__rng)
Main parallel random shuffle step. template<typename _RAIter , typename _RandomNumberGenerator > void __parallel_random_shuffle_drs_pu (_DRSSorterPU< _RAIter, _RandomNumberGenerator > *__pus)
Random shuffle code executed by each thread. template<typename _IIter , typename _OutputIterator , typename _Compare > _OutputIterator __parallel_set_difference (_IIter __begin1, _IIter __end1, _IIter __begin2, _IIter __end2, _OutputIterator __result, _Compare __comp)
template<typename _IIter , typename _OutputIterator , typename _Compare > _OutputIterator __parallel_set_intersection (_IIter __begin1, _IIter __end1, _IIter __begin2, _IIter __end2, _OutputIterator __result, _Compare __comp)
template<typename _IIter , typename _OutputIterator , typename _Operation > _OutputIterator __parallel_set_operation (_IIter __begin1, _IIter __end1, _IIter __begin2, _IIter __end2, _OutputIterator __result, _Operation __op)
template<typename _IIter , typename _OutputIterator , typename _Compare > _OutputIterator __parallel_set_symmetric_difference (_IIter __begin1, _IIter __end1, _IIter __begin2, _IIter __end2, _OutputIterator __result, _Compare __comp)
template<typename _IIter , typename _OutputIterator , typename _Compare > _OutputIterator __parallel_set_union (_IIter __begin1, _IIter __end1, _IIter __begin2, _IIter __end2, _OutputIterator __result, _Compare __comp)
template<bool __stable, typename _RAIter , typename _Compare , typename _Parallelism > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, _Parallelism __parallelism)
template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, balanced_quicksort_tag __parallelism)
Choose balanced quicksort for parallel sorting. template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, default_parallel_tag __parallelism)
Choose multiway mergesort with exact splitting, for parallel sorting. template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, multiway_mergesort_exact_tag __parallelism)
Choose multiway mergesort with exact splitting, for parallel sorting. template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, multiway_mergesort_sampling_tag __parallelism)
Choose multiway mergesort with splitting by sampling, for parallel sorting. template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, multiway_mergesort_tag __parallelism)
Choose multiway mergesort, splitting variant at run-time, for parallel sorting. template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, parallel_tag __parallelism)
Choose a parallel sorting algorithm. template<bool __stable, typename _RAIter , typename _Compare > void __parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, quicksort_tag __parallelism)
Choose quicksort for parallel sorting. template<typename _RAIter , typename _Compare > void __parallel_sort_qs (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)
Unbalanced quicksort main call. template<typename _RAIter , typename _Compare > void __parallel_sort_qs_conquer (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)
Unbalanced quicksort conquer step. template<typename _RAIter , typename _Compare > std::iterator_traits< _RAIter >::difference_type __parallel_sort_qs_divide (_RAIter __begin, _RAIter __end, _Compare __comp, typename std::iterator_traits< _RAIter >::difference_type __pivot_rank, typename std::iterator_traits< _RAIter >::difference_type __num_samples, _ThreadIndex __num_threads)
Unbalanced quicksort divide step. template<typename _RAIter , typename _Compare > void __parallel_sort_qsb (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)
Top-level quicksort routine. template<typename _IIter , class _OutputIterator > _OutputIterator __parallel_unique_copy (_IIter __first, _IIter __last, _OutputIterator __result)
Parallel std::unique_copy(), without explicit equality predicate. template<typename _IIter , class _OutputIterator , class _BinaryPredicate > _OutputIterator __parallel_unique_copy (_IIter __first, _IIter __last, _OutputIterator __result, _BinaryPredicate __binary_pred)
Parallel std::unique_copy(), w/__o explicit equality predicate. template<typename _RAIter , typename _Compare > void __qsb_conquer (_QSBThreadLocal< _RAIter > **__tls, _RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __iam, _ThreadIndex __num_threads, bool __parent_wait)
Quicksort conquer step. template<typename _RAIter , typename _Compare > std::iterator_traits< _RAIter >::difference_type __qsb_divide (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)
Balanced quicksort divide step. template<typename _RAIter , typename _Compare > void __qsb_local_sort_with_helping (_QSBThreadLocal< _RAIter > **__tls, _Compare &__comp, _ThreadIndex __iam, bool __wait)
Quicksort step doing load-balanced local sort. template<typename _RandomNumberGenerator > int __random_number_pow2 (int __logp, _RandomNumberGenerator &__rng)
Generate a random number in [0,2^__logp). template<typename _Size > _Size __rd_log2 (_Size __n)
Calculates the rounded-down logarithm of __n for base 2. template<typename _Tp > _Tp __round_up_to_pow2 (_Tp __x)
Round up to the next greater power of 2. template<typename __RAIter1 , typename __RAIter2 , typename _Pred > __RAIter1 __search_template (__RAIter1 __begin1, __RAIter1 __end1, __RAIter2 __begin2, __RAIter2 __end2, _Pred __pred)
Parallel std::search. template<bool __stable, bool __sentinels, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __sequential_multiway_merge (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, const typename std::iterator_traits< typename std::iterator_traits< _RAIterIterator >::value_type::first_type >::value_type &__sentinel, _DifferenceTp __length, _Compare __comp)
Sequential multi-way merging switch. template<typename _RAIter , typename _RandomNumberGenerator > void __sequential_random_shuffle (_RAIter __begin, _RAIter __end, _RandomNumberGenerator &__rng)
Sequential cache-efficient random shuffle. template<typename _IIter > void __shrink (std::vector< _IIter > &__os_starts, size_t &__count_to_two, size_t &__range_length)
Combines two ranges into one and thus halves the number of ranges. template<typename _IIter > void __shrink_and_double (std::vector< _IIter > &__os_starts, size_t &__count_to_two, size_t &__range_length, const bool __make_twice)
Shrinks and doubles the ranges. void __yield ()
Yield control to another thread, without waiting for the end of the time slice. template<typename _IIter , typename _FunctorType > size_t list_partition (const _IIter __begin, const _IIter __end, _IIter *__starts, size_t *__lengths, const int __num_parts, _FunctorType &__f, int __oversampling=0)
Splits a sequence given by input iterators into parts of almost equal size. template<typename _Tp > const _Tp & max (const _Tp &__a, const _Tp &__b)
Equivalent to std::max. template<typename _Tp > const _Tp & min (const _Tp &__a, const _Tp &__b)
Equivalent to std::min. template<typename _RanSeqs , typename _RankType , typename _RankIterator , typename _Compare > void multiseq_partition (_RanSeqs __begin_seqs, _RanSeqs __end_seqs, _RankType __rank, _RankIterator __begin_offsets, _Compare __comp=std::less< typename std::iterator_traits< typename std::iterator_traits< _RanSeqs >::value_type::first_type >::value_type >())
Splits several sorted sequences at a certain global __rank, resulting in a splitting point for each sequence. The sequences are passed via a sequence of random-access iterator pairs, none of the sequences may be empty. If there are several equal elements across the split, the ones on the __left side will be chosen from sequences with smaller number. template<typename _Tp , typename _RanSeqs , typename _RankType , typename _Compare > _Tp multiseq_selection (_RanSeqs __begin_seqs, _RanSeqs __end_seqs, _RankType __rank, _RankType &__offset, _Compare __comp=std::less< _Tp >())
Selects the element at a certain global __rank from several sorted sequences. template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::exact_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sampling_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sequential_tag)
Multiway Merge Frontend. template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, default_parallel_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, parallel_tag __tag=parallel_tag(0))
template<template< typename _RAI, typename _Cp > class iterator, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 multiway_merge_3_variant (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _DifferenceTp __length, _Compare __comp)
Highly efficient 3-way merging procedure. template<template< typename _RAI, typename _Cp > class iterator, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 multiway_merge_4_variant (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _DifferenceTp __length, _Compare __comp)
Highly efficient 4-way merging procedure. template<bool __stable, typename _RAIterIterator , typename _Compare , typename _DifferenceType > void multiway_merge_exact_splitting (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _DifferenceType __length, _DifferenceType __total_length, _Compare __comp, std::vector< std::pair< _DifferenceType, _DifferenceType > > *__pieces)
Exact splitting for parallel multiway-merge routine. template<typename _LT , typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 multiway_merge_loser_tree (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _DifferenceTp __length, _Compare __comp)
Multi-way merging procedure for a high branching factor, guarded case. template<typename _UnguardedLoserTree , typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 multiway_merge_loser_tree_sentinel (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, const typename std::iterator_traits< typename std::iterator_traits< _RAIterIterator >::value_type::first_type >::value_type &__sentinel, _DifferenceTp __length, _Compare __comp)
Multi-way merging procedure for a high branching factor, requiring sentinels to exist. template<typename _LT , typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 multiway_merge_loser_tree_unguarded (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, const typename std::iterator_traits< typename std::iterator_traits< _RAIterIterator >::value_type::first_type >::value_type &__sentinel, _DifferenceTp __length, _Compare __comp)
Multi-way merging procedure for a high branching factor, unguarded case. template<bool __stable, typename _RAIterIterator , typename _Compare , typename _DifferenceType > void multiway_merge_sampling_splitting (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _DifferenceType __length, _DifferenceType __total_length, _Compare __comp, std::vector< std::pair< _DifferenceType, _DifferenceType > > *__pieces)
Sampling based splitting for parallel multiway-merge routine. template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::exact_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sequential_tag)
Multiway Merge Frontend. template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, default_parallel_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, parallel_tag __tag=parallel_tag(0))
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, sampling_tag __tag)
template<bool __stable, bool __sentinels, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Splitter , typename _Compare > _RAIter3 parallel_multiway_merge (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _Splitter __splitter, _DifferenceTp __length, _Compare __comp, _ThreadIndex __num_threads)
Parallel multi-way merge routine. template<bool __stable, bool __exact, typename _RAIter , typename _Compare > void parallel_sort_mwms (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)
PMWMS main call. template<bool __stable, bool __exact, typename _RAIter , typename _Compare > void parallel_sort_mwms_pu (_PMWMSSortingData< _RAIter > *__sd, _Compare &__comp)
PMWMS code executed by each thread. template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::exact_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sequential_tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, default_parallel_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, parallel_tag __tag=parallel_tag(0))
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, sampling_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::exact_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sequential_tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, default_parallel_tag __tag)
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, parallel_tag __tag=parallel_tag(0))
template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut stable_multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, sampling_tag __tag)

Variables¶

static const int _CASable_bits
Number of bits of _CASable. static const _CASable _CASable_mask
_CASable with the right half of bits set to 1.

typedef unsigned short __gnu_parallel::_BinIndex¶

Type to hold the index of a bin. Since many variables of this type are allocated, it should be chosen as small as possible.

typedef int64_t __gnu_parallel::_CASable¶

Longest compare-and-swappable integer type on this platform.

typedef uint64_t __gnu_parallel::_SequenceIndex¶

Unsigned integer to index __elements. The total number of elements for each algorithm must fit into this type.

typedef uint16_t __gnu_parallel::_ThreadIndex¶

Unsigned integer to index a thread number. The maximum thread number (for each processor) must fit into this type.

enum __gnu_parallel::_AlgorithmStrategy¶

Strategies for run-time algorithm selection:

enum __gnu_parallel::_FindAlgorithm¶

Find algorithms:

enum __gnu_parallel::_MultiwayMergeAlgorithm¶

Merging algorithms:

enum __gnu_parallel::_Parallelism¶

Run-time equivalents for the compile-time tags.

Enumerator

sequential

Not parallel.

parallel_unbalanced

Parallel unbalanced (equal-sized chunks).

parallel_balanced

Parallel balanced (work-stealing).

parallel_omp_loop

Parallel with OpenMP dynamic load-balancing.

parallel_omp_loop_static

Parallel with OpenMP static load-balancing.

parallel_taskqueue

Parallel with OpenMP taskqueue construct.

enum __gnu_parallel::_PartialSumAlgorithm¶

Partial sum algorithms: recursive, linear.

enum __gnu_parallel::_SortAlgorithm¶

Sorting algorithms:

enum __gnu_parallel::_SplittingAlgorithm¶

Sorting/merging algorithms: sampling, __exact.

template<typename _RAIter , typename _DifferenceTp > void __gnu_parallel::__calc_borders (_RAIter __elements, _DifferenceTp __length, _DifferenceTp * __off)¶

Precalculate __advances for Knuth-Morris-Pratt algorithm.

Parameters

Referenced by __search_template().

template<typename _Tp > bool __gnu_parallel::__compare_and_swap (volatile _Tp * __ptr, _Tp __comparand, _Tp __replacement) [inline]¶

Compare-and-swap. Compare *__ptr and __comparand. If equal, let *__ptr=__replacement and return true, return false otherwise.

Parameters

Referenced by __parallel_partition(), __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::pop_back(), and __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::pop_front().

void __gnu_parallel::__decode2 (_CASable __x, int & __a, int & __b) [inline]¶

Decode two integers from one gnu_parallel::_CASable.

Parameters

See also

References _CASable_bits, and _CASable_mask.

Referenced by __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::pop_back(), __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::pop_front(), and __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::push_front().

template<typename _RAIter , typename _DifferenceTp > void __gnu_parallel::__determine_samples (_PMWMSSortingData< _RAIter > * __sd, _DifferenceTp __num_samples)¶

Select _M_samples from a sequence.

Parameters

References __equally_split(), __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_samples, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_source, and __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_starts.

_CASable __gnu_parallel::__encode2 (int __a, int __b) [inline]¶

Encode two integers into one gnu_parallel::_CASable.

Parameters

Returns

See also

References _CASable_bits.

Referenced by __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::_RestrictedBoundedConcurrentQueue(), __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::pop_back(), __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::pop_front(), and __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::push_front().

template<typename _DifferenceType , typename _OutputIterator > _OutputIterator __gnu_parallel::__equally_split (_DifferenceType __n, _ThreadIndex __num_threads, _OutputIterator __s)¶

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.

Parameters

Returns

Referenced by __determine_samples(), __find_template(), __parallel_partial_sum_linear(), __parallel_unique_copy(), __search_template(), and multiway_merge_exact_splitting().

template<typename _DifferenceType > _DifferenceType __gnu_parallel::__equally_split_point (_DifferenceType __n, _ThreadIndex __num_threads, _ThreadIndex __thread_no)¶

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).

Parameters

Returns

Referenced by __for_each_template_random_access_ed().

template<typename _Tp > _Tp __gnu_parallel::__fetch_and_add (volatile _Tp * __ptr, _Tp __addend) [inline]¶

Add a value to a variable, atomically.

Parameters

Referenced by __parallel_partition(), and __gnu_parallel::_RestrictedBoundedConcurrentQueue< _Tp >::push_front().

template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __gnu_parallel::__find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector) [inline]¶

Parallel std::find, switch for different algorithms.

Parameters

Returns

References __find_template(), and __gnu_parallel::_Settings::get().

Referenced by __find_template().

template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __gnu_parallel::__find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector, constant_size_blocks_tag)¶

Parallel std::find, constant block size variant.

Parameters

Returns

See also

References _GLIBCXX_CALL, __gnu_parallel::_Settings::find_initial_block_size, __gnu_parallel::_Settings::find_sequential_search_size, and __gnu_parallel::_Settings::get().

template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __gnu_parallel::__find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector, equal_split_tag)¶

Parallel std::find, equal splitting variant.

Parameters

Returns

References __equally_split(), and _GLIBCXX_CALL.

template<typename _RAIter1 , typename _RAIter2 , typename _Pred , typename _Selector > std::pair< _RAIter1, _RAIter2 > __gnu_parallel::__find_template (_RAIter1 __begin1, _RAIter1 __end1, _RAIter2 __begin2, _Pred __pred, _Selector __selector, growing_blocks_tag)¶

Parallel std::find, growing block size variant.

Parameters

Returns

See also

There are two main differences between the growing blocks and the constant-size blocks variants.

1.

For GB, the block size grows; for CSB, the block size is fixed.

2.

For GB, the blocks are allocated dynamically; for CSB, the blocks are allocated in a predetermined manner, namely spacial round-robin.

References _GLIBCXX_CALL, __gnu_parallel::_Settings::find_scale_factor, __gnu_parallel::_Settings::find_sequential_search_size, and __gnu_parallel::_Settings::get().

template<typename _IIter , typename _UserOp , typename _Functionality , typename _Red , typename _Result > _UserOp __gnu_parallel::__for_each_template_random_access (_IIter __begin, _IIter __end, _UserOp __user_op, _Functionality & __functionality, _Red __reduction, _Result __reduction_start, _Result & __output, typename std::iterator_traits< _IIter >::difference_type __bound, _Parallelism __parallelism_tag)¶

Chose the desired algorithm by evaluating __parallelism_tag.

Parameters

References __for_each_template_random_access_ed(), __for_each_template_random_access_omp_loop(), __for_each_template_random_access_workstealing(), parallel_omp_loop, parallel_omp_loop_static, and parallel_unbalanced.

template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __gnu_parallel::__for_each_template_random_access_ed (_RAIter __begin, _RAIter __end, _Op __o, _Fu & __f, _Red __r, _Result __base, _Result & __output, typename std::iterator_traits< _RAIter >::difference_type __bound)¶

Embarrassingly parallel algorithm for random access iterators, using hand-crafted parallelization by equal splitting the work.

Parameters

Returns

References __equally_split_point().

Referenced by __for_each_template_random_access().

template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __gnu_parallel::__for_each_template_random_access_omp_loop (_RAIter __begin, _RAIter __end, _Op __o, _Fu & __f, _Red __r, _Result __base, _Result & __output, typename std::iterator_traits< _RAIter >::difference_type __bound)¶

Embarrassingly parallel algorithm for random access iterators, using an OpenMP for loop.

Parameters

Returns

Referenced by __for_each_template_random_access().

template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __gnu_parallel::__for_each_template_random_access_omp_loop_static (_RAIter __begin, _RAIter __end, _Op __o, _Fu & __f, _Red __r, _Result __base, _Result & __output, typename std::iterator_traits< _RAIter >::difference_type __bound)¶

Embarrassingly parallel algorithm for random access iterators, using an OpenMP for loop with static scheduling.

Parameters

Returns

template<typename _RAIter , typename _Op , typename _Fu , typename _Red , typename _Result > _Op __gnu_parallel::__for_each_template_random_access_workstealing (_RAIter __begin, _RAIter __end, _Op __op, _Fu & __f, _Red __r, _Result __base, _Result & __output, typename std::iterator_traits< _RAIter >::difference_type __bound)¶

Work stealing algorithm for random access iterators. Uses O(1) additional memory. Synchronization at job lists is done with atomic operations.

Parameters

Returns

References __yield(), _GLIBCXX_CALL, __gnu_parallel::_Job< _DifferenceTp >::_M_first, __gnu_parallel::_Job< _DifferenceTp >::_M_last, __gnu_parallel::_Job< _DifferenceTp >::_M_load, __gnu_parallel::_Settings::cache_line_size, __gnu_parallel::_Settings::get(), and min().

Referenced by __for_each_template_random_access().

template<typename _IIter , typename _Compare > bool __gnu_parallel::__is_sorted (_IIter __begin, _IIter __end, _Compare __comp)¶

Check whether [__begin, __end) is sorted according to __comp.

Parameters

Returns

Referenced by __sequential_multiway_merge(), multiway_merge_loser_tree_sentinel(), and parallel_multiway_merge().

template<typename _RAIter , typename _Compare > _RAIter __gnu_parallel::__median_of_three_iterators (_RAIter __a, _RAIter __b, _RAIter __c, _Compare __comp)¶

Compute the median of three referenced elements, according to __comp.

Parameters

Referenced by __qsb_divide().

template<typename _RAIter1 , typename _RAIter2 , typename _OutputIterator , typename _DifferenceTp , typename _Compare > _OutputIterator __gnu_parallel::__merge_advance (_RAIter1 & __begin1, _RAIter1 __end1, _RAIter2 & __begin2, _RAIter2 __end2, _OutputIterator __target, _DifferenceTp __max_length, _Compare __comp) [inline]¶

Merge routine being able to merge only the __max_length smallest elements. The __begin iterators are advanced accordingly, they might not reach __end, in contrast to the usual variant. Static switch on whether to use the conditional-move variant.

Parameters

Returns

References __merge_advance_movc(), and _GLIBCXX_CALL.

Referenced by __parallel_merge_advance(), and __sequential_multiway_merge().

template<typename _RAIter1 , typename _RAIter2 , typename _OutputIterator , typename _DifferenceTp , typename _Compare > _OutputIterator __gnu_parallel::__merge_advance_movc (_RAIter1 & __begin1, _RAIter1 __end1, _RAIter2 & __begin2, _RAIter2 __end2, _OutputIterator __target, _DifferenceTp __max_length, _Compare __comp)¶

Merge routine being able to merge only the __max_length smallest elements. The __begin iterators are advanced accordingly, they might not reach __end, in contrast to the usual variant. Specially designed code should allow the compiler to generate conditional moves instead of branches.

Parameters

Returns

Referenced by __merge_advance().

template<typename _RAIter1 , typename _RAIter2 , typename _OutputIterator , typename _DifferenceTp , typename _Compare > _OutputIterator __gnu_parallel::__merge_advance_usual (_RAIter1 & __begin1, _RAIter1 __end1, _RAIter2 & __begin2, _RAIter2 __end2, _OutputIterator __target, _DifferenceTp __max_length, _Compare __comp)¶

Merge routine being able to merge only the __max_length smallest elements. The __begin iterators are advanced accordingly, they might not reach __end, in contrast to the usual variant.

Parameters

Returns

template<typename _RAIter1 , typename _RAIter3 , typename _Compare > _RAIter3 __gnu_parallel::__parallel_merge_advance (_RAIter1 & __begin1, _RAIter1 __end1, _RAIter1 & __begin2, _RAIter1 __end2, _RAIter3 __target, typename std::iterator_traits< _RAIter1 >::difference_type __max_length, _Compare __comp) [inline]¶

Parallel merge routine being able to merge only the __max_length smallest elements. The __begin iterators are advanced accordingly, they might not reach __end, in contrast to the usual variant. The functionality is projected onto parallel_multiway_merge.

Parameters

Returns

References multiway_merge_exact_splitting(), and parallel_multiway_merge().

template<typename _RAIter1 , typename _RAIter2 , typename _RAIter3 , typename _Compare > _RAIter3 __gnu_parallel::__parallel_merge_advance (_RAIter1 & __begin1, _RAIter1 __end1, _RAIter2 & __begin2, _RAIter2 __end2, _RAIter3 __target, typename std::iterator_traits< _RAIter1 >::difference_type __max_length, _Compare __comp) [inline]¶

Merge routine fallback to sequential in case the iterators of the two input sequences are of different type.

Parameters

Returns

References __merge_advance().

template<typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_nth_element (_RAIter __begin, _RAIter __nth, _RAIter __end, _Compare __comp)¶

Parallel implementation of std::nth_element().

Parameters

References __parallel_partition(), _GLIBCXX_CALL, __gnu_parallel::_Settings::get(), std::max(), __gnu_parallel::_Settings::nth_element_minimal_n, and __gnu_parallel::_Settings::partition_minimal_n.

Referenced by __parallel_partial_sort().

template<typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_partial_sort (_RAIter __begin, _RAIter __middle, _RAIter __end, _Compare __comp)¶

Parallel implementation of std::partial_sort().

Parameters

References __parallel_nth_element().

template<typename _IIter , typename _OutputIterator , typename _BinaryOperation > _OutputIterator __gnu_parallel::__parallel_partial_sum (_IIter __begin, _IIter __end, _OutputIterator __result, _BinaryOperation __bin_op)¶

Parallel partial sum front-__end.

Parameters

Returns

References __parallel_partial_sum_linear(), _GLIBCXX_CALL, and __gnu_parallel::_Settings::get().

template<typename _IIter , typename _OutputIterator , typename _BinaryOperation > _OutputIterator __gnu_parallel::__parallel_partial_sum_basecase (_IIter __begin, _IIter __end, _OutputIterator __result, _BinaryOperation __bin_op, typename std::iterator_traits< _IIter >::value_type __value)¶

Base case prefix sum routine.

Parameters

Returns

Referenced by __parallel_partial_sum_linear().

template<typename _IIter , typename _OutputIterator , typename _BinaryOperation > _OutputIterator __gnu_parallel::__parallel_partial_sum_linear (_IIter __begin, _IIter __end, _OutputIterator __result, _BinaryOperation __bin_op, typename std::iterator_traits< _IIter >::difference_type __n)¶

Parallel partial sum implementation, two-phase approach, no recursion.

Parameters

Returns

References __equally_split(), __parallel_partial_sum_basecase(), __gnu_parallel::_Settings::get(), and __gnu_parallel::_Settings::partial_sum_dilation.

Referenced by __parallel_partial_sum().

template<typename _RAIter , typename _Predicate > std::iterator_traits< _RAIter >::difference_type __gnu_parallel::__parallel_partition (_RAIter __begin, _RAIter __end, _Predicate __pred, _ThreadIndex __num_threads)¶

Parallel implementation of std::partition.

Parameters

Returns

References __compare_and_swap(), __fetch_and_add(), _GLIBCXX_CALL, _GLIBCXX_VOLATILE, __gnu_parallel::_Settings::get(), __gnu_parallel::_Settings::partition_chunk_share, and __gnu_parallel::_Settings::partition_chunk_size.

Referenced by __parallel_nth_element(), __parallel_sort_qs_divide(), and __qsb_divide().

template<typename _RAIter , typename _RandomNumberGenerator > void __gnu_parallel::__parallel_random_shuffle (_RAIter __begin, _RAIter __end, _RandomNumberGenerator __rng = _RandomNumber()) [inline]¶

Parallel random public call.

Parameters

References __parallel_random_shuffle_drs().

template<typename _RAIter , typename _RandomNumberGenerator > void __gnu_parallel::__parallel_random_shuffle_drs (_RAIter __begin, _RAIter __end, typename std::iterator_traits< _RAIter >::difference_type __n, _ThreadIndex __num_threads, _RandomNumberGenerator & __rng)¶

Main parallel random shuffle step.

Parameters

References __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::__bins_end, __parallel_random_shuffle_drs_pu(), __rd_log2(), __round_up_to_pow2(), __sequential_random_shuffle(), _GLIBCXX_CALL, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_bin_proc, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_bins_begin, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_dist, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_num_bins, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_num_bits, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_num_threads, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_sd, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_seed, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_starts, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_temporaries, __gnu_parallel::_Settings::get(), __gnu_parallel::_Settings::L2_cache_size, std::min(), and __gnu_parallel::_Settings::TLB_size.

Referenced by __parallel_random_shuffle().

template<typename _RAIter , typename _RandomNumberGenerator > void __gnu_parallel::__parallel_random_shuffle_drs_pu (_DRSSorterPU< _RAIter, _RandomNumberGenerator > * __pus)¶

Random shuffle code executed by each thread.

Parameters

References __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::__bins_end, __random_number_pow2(), __sequential_random_shuffle(), __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_bin_proc, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_bins_begin, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_dist, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_num_bins, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_num_bits, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_num_threads, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_sd, __gnu_parallel::_DRSSorterPU< _RAIter, _RandomNumberGenerator >::_M_seed, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_source, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_starts, __gnu_parallel::_DRandomShufflingGlobalData< _RAIter >::_M_temporaries, and std::partial_sum().

Referenced by __parallel_random_shuffle_drs().

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, balanced_quicksort_tag __parallelism) [inline]¶

Choose balanced quicksort for parallel sorting.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), __parallel_sort_qsb(), and _GLIBCXX_CALL.

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, default_parallel_tag __parallelism) [inline]¶

Choose multiway mergesort with exact splitting, for parallel sorting.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), and _GLIBCXX_CALL.

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, multiway_mergesort_exact_tag __parallelism) [inline]¶

Choose multiway mergesort with exact splitting, for parallel sorting.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), and _GLIBCXX_CALL.

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, multiway_mergesort_sampling_tag __parallelism) [inline]¶

Choose multiway mergesort with splitting by sampling, for parallel sorting.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), and _GLIBCXX_CALL.

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, multiway_mergesort_tag __parallelism) [inline]¶

Choose multiway mergesort, splitting variant at run-time, for parallel sorting.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), _GLIBCXX_CALL, and __gnu_parallel::_Settings::get().

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, parallel_tag __parallelism) [inline]¶

Choose a parallel sorting algorithm.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), __parallel_sort_qs(), __parallel_sort_qsb(), _GLIBCXX_CALL, and __gnu_parallel::_Settings::get().

template<bool __stable, typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort (_RAIter __begin, _RAIter __end, _Compare __comp, quicksort_tag __parallelism) [inline]¶

Choose quicksort for parallel sorting.

Parameters

Template Parameters

References __gnu_parallel::parallel_tag::__get_num_threads(), __parallel_sort_qs(), and _GLIBCXX_CALL.

template<typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort_qs (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)¶

Unbalanced quicksort main call.

Parameters

References __parallel_sort_qs_conquer(), and _GLIBCXX_CALL.

Referenced by __parallel_sort(), and __parallel_sort().

template<typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort_qs_conquer (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)¶

Unbalanced quicksort conquer step.

Parameters

References __parallel_sort_qs_conquer(), __parallel_sort_qs_divide(), and __gnu_parallel::_Settings::get().

Referenced by __parallel_sort_qs(), and __parallel_sort_qs_conquer().

template<typename _RAIter , typename _Compare > std::iterator_traits< _RAIter >::difference_type __gnu_parallel::__parallel_sort_qs_divide (_RAIter __begin, _RAIter __end, _Compare __comp, typename std::iterator_traits< _RAIter >::difference_type __pivot_rank, typename std::iterator_traits< _RAIter >::difference_type __num_samples, _ThreadIndex __num_threads)¶

Unbalanced quicksort divide step.

Parameters

References __parallel_partition(), and std::min().

Referenced by __parallel_sort_qs_conquer().

template<typename _RAIter , typename _Compare > void __gnu_parallel::__parallel_sort_qsb (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)¶

Top-level quicksort routine.

Parameters

References __qsb_conquer(), __rd_log2(), _GLIBCXX_CALL, and __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_elements_leftover.

Referenced by __parallel_sort(), and __parallel_sort().

template<typename _IIter , class _OutputIterator > _OutputIterator __gnu_parallel::__parallel_unique_copy (_IIter __first, _IIter __last, _OutputIterator __result) [inline]¶

Parallel std::unique_copy(), without explicit equality predicate.

Parameters

Returns

References __parallel_unique_copy().

template<typename _IIter , class _OutputIterator , class _BinaryPredicate > _OutputIterator __gnu_parallel::__parallel_unique_copy (_IIter __first, _IIter __last, _OutputIterator __result, _BinaryPredicate __binary_pred)¶

Parallel std::unique_copy(), w/__o explicit equality predicate.

Parameters

Returns

References __equally_split(), and _GLIBCXX_CALL.

Referenced by __parallel_unique_copy().

template<typename _RAIter , typename _Compare > void __gnu_parallel::__qsb_conquer (_QSBThreadLocal< _RAIter > ** __tls, _RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __iam, _ThreadIndex __num_threads, bool __parent_wait)¶

Quicksort conquer step.

Parameters

References __qsb_conquer(), __qsb_divide(), __qsb_local_sort_with_helping(), __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_elements_leftover, and __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_initial.

Referenced by __parallel_sort_qsb(), and __qsb_conquer().

template<typename _RAIter , typename _Compare > std::iterator_traits< _RAIter >::difference_type __gnu_parallel::__qsb_divide (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)¶

Balanced quicksort divide step.

Parameters

Precondition

References __median_of_three_iterators(), and __parallel_partition().

Referenced by __qsb_conquer().

template<typename _RAIter , typename _Compare > void __gnu_parallel::__qsb_local_sort_with_helping (_QSBThreadLocal< _RAIter > ** __tls, _Compare & __comp, _ThreadIndex __iam, bool __wait)¶

Quicksort step doing load-balanced local sort.

Parameters

References __yield(), _GLIBCXX_PARALLEL_ASSERTIONS, __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_elements_leftover, __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_initial, __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_leftover_parts, __gnu_parallel::_QSBThreadLocal< _RAIter >::_M_num_threads, __gnu_parallel::_Settings::get(), and __gnu_parallel::_Settings::sort_qsb_base_case_maximal_n.

Referenced by __qsb_conquer().

template<typename _RandomNumberGenerator > int __gnu_parallel::__random_number_pow2 (int __logp, _RandomNumberGenerator & __rng) [inline]¶

Generate a random number in [0,2^__logp).

Parameters

Referenced by __parallel_random_shuffle_drs_pu(), and __sequential_random_shuffle().

template<typename _Size > _Size __gnu_parallel::__rd_log2 (_Size __n) [inline]¶

Calculates the rounded-down logarithm of __n for base 2.

Parameters

Returns

Referenced by __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_LoserTreeBase(), __parallel_random_shuffle_drs(), __parallel_sort_qsb(), __round_up_to_pow2(), __sequential_random_shuffle(), multiseq_partition(), and multiseq_selection().

template<typename _Tp > _Tp __gnu_parallel::__round_up_to_pow2 (_Tp __x)¶

Round up to the next greater power of 2.

Parameters

References __rd_log2().

Referenced by __parallel_random_shuffle_drs(), __sequential_random_shuffle(), and multiseq_selection().

template<typename __RAIter1 , typename __RAIter2 , typename _Pred > __RAIter1 __gnu_parallel::__search_template (__RAIter1 __begin1, __RAIter1 __end1, __RAIter2 __begin2, __RAIter2 __end2, _Pred __pred)¶

Parallel std::search.

Parameters

Returns

References __calc_borders(), __equally_split(), _GLIBCXX_CALL, and std::min().

template<bool __stable, bool __sentinels, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __gnu_parallel::__sequential_multiway_merge (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, const typename std::iterator_traits< typename std::iterator_traits< _RAIterIterator >::value_type::first_type >::value_type & __sentinel, _DifferenceTp __length, _Compare __comp)¶

Sequential multi-way merging switch. The _GLIBCXX_PARALLEL_DECISION is based on the branching factor and runtime settings.

Parameters

Returns

References __is_sorted(), __merge_advance(), _GLIBCXX_CALL, and _GLIBCXX_PARALLEL_LENGTH.

Referenced by multiway_merge(), and multiway_merge_sentinels().

template<typename _RAIter , typename _RandomNumberGenerator > void __gnu_parallel::__sequential_random_shuffle (_RAIter __begin, _RAIter __end, _RandomNumberGenerator & __rng)¶

Sequential cache-efficient random shuffle.

Parameters

References __random_number_pow2(), __rd_log2(), __round_up_to_pow2(), __sequential_random_shuffle(), __gnu_parallel::_Settings::get(), __gnu_parallel::_Settings::L2_cache_size, std::min(), std::partial_sum(), and __gnu_parallel::_Settings::TLB_size.

Referenced by __parallel_random_shuffle_drs(), __parallel_random_shuffle_drs_pu(), and __sequential_random_shuffle().

template<typename _IIter > void __gnu_parallel::__shrink (std::vector< _IIter > & __os_starts, size_t & __count_to_two, size_t & __range_length)¶

Combines two ranges into one and thus halves the number of ranges.

Parameters

Referenced by __shrink_and_double().

template<typename _IIter > void __gnu_parallel::__shrink_and_double (std::vector< _IIter > & __os_starts, size_t & __count_to_two, size_t & __range_length, const bool __make_twice)¶

Shrinks and doubles the ranges.

Parameters

References __shrink().

Referenced by list_partition().

void __gnu_parallel::__yield () [inline]¶

Yield control to another thread, without waiting for the end of the time slice.

Referenced by __for_each_template_random_access_workstealing(), and __qsb_local_sort_with_helping().

template<typename _IIter , typename _FunctorType > size_t __gnu_parallel::list_partition (const _IIter __begin, const _IIter __end, _IIter * __starts, size_t * __lengths, const int __num_parts, _FunctorType & __f, int __oversampling = 0)¶

Splits a sequence given by input iterators into parts of almost equal size. The function needs only one pass over the sequence.

Parameters

Returns

References __shrink_and_double().

template<typename _Tp > const _Tp & __gnu_parallel::max (const _Tp & __a, const _Tp & __b) [inline]¶

Equivalent to std::max.

template<typename _Tp > const _Tp & __gnu_parallel::min (const _Tp & __a, const _Tp & __b) [inline]¶

Equivalent to std::min.

Referenced by __for_each_template_random_access_workstealing().

template<typename _RanSeqs , typename _RankType , typename _RankIterator , typename _Compare > void __gnu_parallel::multiseq_partition (_RanSeqs __begin_seqs, _RanSeqs __end_seqs, _RankType __rank, _RankIterator __begin_offsets, _Compare __comp = std::less< typename std::iterator_traits<typename std::iterator_traits<_RanSeqs>::value_type:: first_type>::value_type>())¶

Splits several sorted sequences at a certain global __rank, resulting in a splitting point for each sequence. The sequences are passed via a sequence of random-access iterator pairs, none of the sequences may be empty. If there are several equal elements across the split, the ones on the __left side will be chosen from sequences with smaller number.

Parameters

References __rd_log2(), _GLIBCXX_CALL, std::distance(), std::max(), and std::min().

Referenced by multiway_merge_exact_splitting().

template<typename _Tp , typename _RanSeqs , typename _RankType , typename _Compare > _Tp __gnu_parallel::multiseq_selection (_RanSeqs __begin_seqs, _RanSeqs __end_seqs, _RankType __rank, _RankType & __offset, _Compare __comp = std::less<_Tp>())¶

Selects the element at a certain global __rank from several sorted sequences. The sequences are passed via a sequence of random-access iterator pairs, none of the sequences may be empty.

Parameters

References __rd_log2(), __round_up_to_pow2(), _GLIBCXX_CALL, std::distance(), std::max(), and std::min().

template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut __gnu_parallel::multiway_merge (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sequential_tag)¶

Multiway Merge Frontend. Merge the sequences specified by seqs_begin and __seqs_end into __target. __seqs_begin and __seqs_end must point to a sequence of pairs. These pairs must contain an iterator to the beginning of a sequence in their first entry and an iterator the _M_end of the same sequence in their second entry.

Ties are broken arbitrarily. See stable_multiway_merge for a variant that breaks ties by sequence number but is slower.

The first entries of the pairs (i.e. the begin iterators) will be moved forward.

The output sequence has to provide enough space for all elements that are written to it.

This function will merge the input sequences:

• not stable
• parallel, depending on the input size and Settings
• using sampling for splitting
• not using sentinels

Example:

  int sequences[10][10];


  for (int __i = 0; __i < 10; ++__i)


    for (int __j = 0; __i < 10; ++__j)


      sequences[__i][__j] = __j;


  int __out[33];


  std::vector<std::pair<int*> > seqs;


  for (int __i = 0; __i < 10; ++__i)


    { seqs.push(std::make_pair<int*>(sequences[__i],


                                     sequences[__i] + 10)) }


  multiway_merge(seqs.begin(), seqs.end(), __target, std::less<int>(), 33);

See also

Precondition

Postcondition

Template Parameters

Parameters

Returns

References __sequential_multiway_merge(), and _GLIBCXX_CALL.

template<template< typename _RAI, typename _Cp > class iterator, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __gnu_parallel::multiway_merge_3_variant (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _DifferenceTp __length, _Compare __comp)¶

Highly efficient 3-way merging procedure. Merging is done with the algorithm implementation described by Peter Sanders. Basically, the idea is to minimize the number of necessary comparison after merging an element. The implementation trick that makes this fast is that the order of the sequences is stored in the instruction pointer (translated into labels in C++).

This works well for merging up to 4 sequences.

Note that making the merging stable does not come at a performance hit.

Whether the merging is done guarded or unguarded is selected by the used iterator class.

Parameters

Returns

References _GLIBCXX_CALL.

template<template< typename _RAI, typename _Cp > class iterator, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __gnu_parallel::multiway_merge_4_variant (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _DifferenceTp __length, _Compare __comp)¶

Highly efficient 4-way merging procedure. Merging is done with the algorithm implementation described by Peter Sanders. Basically, the idea is to minimize the number of necessary comparison after merging an element. The implementation trick that makes this fast is that the order of the sequences is stored in the instruction pointer (translated into goto labels in C++).

This works well for merging up to 4 sequences.

Note that making the merging stable does not come at a performance hit.

Whether the merging is done guarded or unguarded is selected by the used iterator class.

Parameters

Returns

References _GLIBCXX_CALL.

template<bool __stable, typename _RAIterIterator , typename _Compare , typename _DifferenceType > void __gnu_parallel::multiway_merge_exact_splitting (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _DifferenceType __length, _DifferenceType __total_length, _Compare __comp, std::vector< std::pair< _DifferenceType, _DifferenceType > > * __pieces)¶

Exact splitting for parallel multiway-merge routine. None of the passed sequences may be empty.

References __equally_split(), _GLIBCXX_PARALLEL_LENGTH, and multiseq_partition().

Referenced by __parallel_merge_advance().

template<typename _LT , typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __gnu_parallel::multiway_merge_loser_tree (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _DifferenceTp __length, _Compare __comp)¶

Multi-way merging procedure for a high branching factor, guarded case. This merging variant uses a LoserTree class as selected by _LT.

Stability is selected through the used LoserTree class _LT.

At least one non-empty sequence is required.

Parameters

Returns

References _GLIBCXX_CALL, and _GLIBCXX_PARALLEL_LENGTH.

template<typename _UnguardedLoserTree , typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __gnu_parallel::multiway_merge_loser_tree_sentinel (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, const typename std::iterator_traits< typename std::iterator_traits< _RAIterIterator >::value_type::first_type >::value_type & __sentinel, _DifferenceTp __length, _Compare __comp)¶

Multi-way merging procedure for a high branching factor, requiring sentinels to exist.

Template Parameters

Parameters

Returns

References __is_sorted(), and _GLIBCXX_CALL.

template<typename _LT , typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Compare > _RAIter3 __gnu_parallel::multiway_merge_loser_tree_unguarded (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, const typename std::iterator_traits< typename std::iterator_traits< _RAIterIterator >::value_type::first_type >::value_type & __sentinel, _DifferenceTp __length, _Compare __comp)¶

Multi-way merging procedure for a high branching factor, unguarded case. Merging is done using the LoserTree class _LT.

Stability is selected by the used LoserTrees.

Precondition

Parameters

Returns

References _GLIBCXX_CALL.

template<bool __stable, typename _RAIterIterator , typename _Compare , typename _DifferenceType > void __gnu_parallel::multiway_merge_sampling_splitting (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _DifferenceType __length, _DifferenceType __total_length, _Compare __comp, std::vector< std::pair< _DifferenceType, _DifferenceType > > * __pieces)¶

Sampling based splitting for parallel multiway-merge routine.

References _GLIBCXX_PARALLEL_LENGTH, __gnu_parallel::_Settings::get(), and __gnu_parallel::_Settings::merge_oversampling.

template<typename _RAIterPairIterator , typename _RAIterOut , typename _DifferenceTp , typename _Compare > _RAIterOut __gnu_parallel::multiway_merge_sentinels (_RAIterPairIterator __seqs_begin, _RAIterPairIterator __seqs_end, _RAIterOut __target, _DifferenceTp __length, _Compare __comp, __gnu_parallel::sequential_tag)¶

Multiway Merge Frontend. Merge the sequences specified by seqs_begin and __seqs_end into __target. __seqs_begin and __seqs_end must point to a sequence of pairs. These pairs must contain an iterator to the beginning of a sequence in their first entry and an iterator the _M_end of the same sequence in their second entry.

Ties are broken arbitrarily. See stable_multiway_merge for a variant that breaks ties by sequence number but is slower.

The first entries of the pairs (i.e. the begin iterators) will be moved forward accordingly.

The output sequence has to provide enough space for all elements that are written to it.

This function will merge the input sequences:

• not stable
• parallel, depending on the input size and Settings
• using sampling for splitting
• using sentinels

You have to take care that the element the _M_end iterator points to is readable and contains a value that is greater than any other non-sentinel value in all sequences.

Example:

  int sequences[10][11];


  for (int __i = 0; __i < 10; ++__i)


    for (int __j = 0; __i < 11; ++__j)


      sequences[__i][__j] = __j; // __last one is sentinel!


  int __out[33];


  std::vector<std::pair<int*> > seqs;


  for (int __i = 0; __i < 10; ++__i)


    { seqs.push(std::make_pair<int*>(sequences[__i],


                                     sequences[__i] + 10)) }


  multiway_merge(seqs.begin(), seqs.end(), __target, std::less<int>(), 33);

Precondition

Postcondition

See also

Template Parameters

Parameters

Returns

References __sequential_multiway_merge(), and _GLIBCXX_CALL.

template<bool __stable, bool __sentinels, typename _RAIterIterator , typename _RAIter3 , typename _DifferenceTp , typename _Splitter , typename _Compare > _RAIter3 __gnu_parallel::parallel_multiway_merge (_RAIterIterator __seqs_begin, _RAIterIterator __seqs_end, _RAIter3 __target, _Splitter __splitter, _DifferenceTp __length, _Compare __comp, _ThreadIndex __num_threads)¶

Parallel multi-way merge routine. The _GLIBCXX_PARALLEL_DECISION is based on the branching factor and runtime settings.

Must not be called if the number of sequences is 1.

Template Parameters

Parameters

Returns

References __is_sorted(), _GLIBCXX_CALL, _GLIBCXX_PARALLEL_LENGTH, __gnu_parallel::_Settings::get(), and __gnu_parallel::_Settings::merge_oversampling.

Referenced by __parallel_merge_advance().

template<bool __stable, bool __exact, typename _RAIter , typename _Compare > void __gnu_parallel::parallel_sort_mwms (_RAIter __begin, _RAIter __end, _Compare __comp, _ThreadIndex __num_threads)¶

PMWMS main call.

Parameters

References _GLIBCXX_CALL, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_num_threads, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_offsets, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_pieces, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_samples, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_source, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_starts, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_temporary, __gnu_parallel::_Settings::get(), and __gnu_parallel::_Settings::sort_mwms_oversampling.

template<bool __stable, bool __exact, typename _RAIter , typename _Compare > void __gnu_parallel::parallel_sort_mwms_pu (_PMWMSSortingData< _RAIter > * __sd, _Compare & __comp)¶

PMWMS code executed by each thread.

Parameters

References __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_num_threads, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_pieces, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_source, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_starts, __gnu_parallel::_PMWMSSortingData< _RAIter >::_M_temporary, __gnu_parallel::_Settings::get(), __gnu_parallel::_Settings::sort_mwms_oversampling, and std::uninitialized_copy().

const int __gnu_parallel::_CASable_bits [static]¶

Number of bits of _CASable.

Referenced by __decode2(), and __encode2().

const _CASable __gnu_parallel::_CASable_mask [static]¶

_CASable with the right half of bits set to 1.

Referenced by __decode2().