__gnu_parallel(3cxx) | __gnu_parallel(3cxx) |
NAME¶
__gnu_parallel -SYNOPSIS¶
Classes¶
struct __accumulate_binop_reduct
Typedefs¶
typedef unsigned short _BinIndex
Enumerations¶
enum _AlgorithmStrategy { heuristic, force_sequential, force_parallel }
Functions¶
template<typename _Tp > _Tp __add_omp (volatile _Tp *__ptr, _Tp __addend)
Variables¶
static const int _CASable_bits
Detailed Description¶
GNU parallel code for public use.Typedef Documentation¶
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. Definition at line 47 of file random_shuffle.h.typedef int64_t __gnu_parallel::_CASable¶
Longest compare-and-swappable integer type on this platform. Definition at line 127 of file types.h.typedef uint64_t __gnu_parallel::_SequenceIndex¶
Unsigned integer to index __elements. The total number of elements for each algorithm must fit into this type. Definition at line 117 of file types.h.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. Definition at line 123 of file types.h.Enumeration Type Documentation¶
enum __gnu_parallel::_AlgorithmStrategy¶
Strategies for run-time algorithm selection: Definition at line 67 of file types.h.enum __gnu_parallel::_FindAlgorithm¶
Find algorithms: Definition at line 106 of file types.h.enum __gnu_parallel::_MultiwayMergeAlgorithm¶
Merging algorithms: Definition at line 85 of file types.h.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. Definition at line 91 of file types.h.enum __gnu_parallel::_SortAlgorithm¶
Sorting algorithms: Definition at line 76 of file types.h.enum __gnu_parallel::_SplittingAlgorithm¶
Sorting/merging algorithms: sampling, __exact. Definition at line 98 of file types.h.Function Documentation¶
template<typename _RAIter , typename _DifferenceTp > void __gnu_parallel::__calc_borders (_RAIter__elements, _DifferenceTp__length, _DifferenceTp *__off)¶
Precalculate __advances for Knuth-Morris-Pratt algorithm. Parameters:__elements Begin iterator of sequence to search
for.
__length Length of sequence to search for.
__off Returned __offsets.
Definition at line 51 of file search.h.
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:__ptr Pointer to signed integer.
__comparand Compare value.
__replacement Replacement value.
Definition at line 108 of file parallel/compatibility.h.
Referenced by __parallel_partition(),
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::pop_back(), and
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::pop_front().
void __gnu_parallel::__decode2 (_CASable__x, int &__a, int &__b) [inline]¶
Decode two integers from one gnu_parallel::_CASable. Parameters:__x __gnu_parallel::_CASable to decode integers
from.
__a First integer, to be decoded from the most-significant
_CASable_bits/2 bits of __x.
__b Second integer, to be encoded in the least-significant
_CASable_bits/2 bits of __x.
See also:
__encode2
Definition at line 133 of file parallel/base.h.
References _CASable_bits, and _CASable_mask.
Referenced by __gnu_parallel::_RestrictedBoundedConcurrentQueue< pair<
_RAIter, _RAIter > >::pop_back(),
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::pop_front(), and
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::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:__sd Pointer to algorithm data. _Result will be
placed in __sd->_M_samples.
__num_samples Number of _M_samples to select.
Definition at line 97 of file multiway_mergesort.h.
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:__a First integer, to be encoded in the
most-significant _CASable_bits/2 bits.
__b Second integer, to be encoded in the least-significant
_CASable_bits/2 bits.
Returns:
value encoding __a and __b.
See also:
__decode2
Definition at line 119 of file parallel/base.h.
References _CASable_bits.
Referenced by __gnu_parallel::_RestrictedBoundedConcurrentQueue< pair<
_RAIter, _RAIter > >::_RestrictedBoundedConcurrentQueue(),
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::pop_back(),
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::pop_front(), and
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::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:__n Number of elements
__num_threads Number of parts
__s Splitters
Returns:
End of __splitter sequence, i.e.
__s+__num_threads+1
Definition at line 48 of file equally_split.h.
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:__n Number of elements
__num_threads Number of parts
__thread_no Number of threads
Returns:
splitting point
Definition at line 75 of file equally_split.h.
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:__ptr Pointer to a signed integer.
__addend Value to add.
Definition at line 74 of file parallel/compatibility.h.
Referenced by __parallel_partition(), and
__gnu_parallel::_RestrictedBoundedConcurrentQueue< pair< _RAIter,
_RAIter > >::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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence. Must have same length as
first sequence.
__pred Find predicate.
__selector _Functionality (e. g. std::find_if(), std::equal(),...)
Returns:
Place of finding in both sequences.
Definition at line 60 of file find.h.
References __gnu_parallel::_Settings::get(), and std::make_pair().
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence. Second __sequence must have
same length as first sequence.
__pred Find predicate.
__selector _Functionality (e. g. std::find_if(), std::equal(),...)
Returns:
Place of finding in both sequences.
Definition at line 97 of file find.h.
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence. Second __sequence must have
same length as first sequence.
__pred Find predicate.
__selector _Functionality (e. g. std::find_if(), std::equal(),...)
Returns:
Place of finding in both sequences.
See also:
__gnu_parallel::_Settings::find_sequential_search_size
__gnu_parallel::_Settings::find_scale_factor
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.
Definition at line 185 of file find.h.
References _GLIBCXX_CALL, __gnu_parallel::_Settings::find_scale_factor,
__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, constant_size_blocks_tag)¶
Parallel std::find, constant block size variant. Parameters:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence. Second __sequence must have
same length as first sequence.
__pred Find predicate.
__selector _Functionality (e. g. std::find_if(), std::equal(),...)
Returns:
Place of finding in both sequences.
See also:
__gnu_parallel::_Settings::find_sequential_search_size
__gnu_parallel::_Settings::find_block_size 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.
Definition at line 315 of file find.h.
References _GLIBCXX_CALL, __gnu_parallel::_Settings::find_initial_block_size,
__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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__user_op A user-specified functor (comparator, predicate, associative
operator,...)
__functionality functor to process an element with __user_op
(depends on desired functionality, e. g. accumulate, for_each,...
__reduction Reduction functor.
__reduction_start Initial value for reduction.
__output Output iterator.
__bound Maximum number of elements processed.
__parallelism_tag Parallelization method
Definition at line 61 of file for_each.h.
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:__begin Begin iterator of element sequence.
__end End iterator of element sequence.
__o User-supplied functor (comparator, predicate, adding functor, ...)
__f Functor to 'process' an element with __op (depends on desired
functionality, e. g. for std::for_each(), ...).
__r Functor to 'add' a single __result to the already processed elements
(depends on functionality).
__base Base value for reduction.
__output Pointer to position where final result is written to
__bound Maximum number of elements processed (e. g. for
std::count_n()).
Returns:
User-supplied functor (that may contain a part of the
result).
Definition at line 67 of file par_loop.h.
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:__begin Begin iterator of element sequence.
__end End iterator of element sequence.
__o User-supplied functor (comparator, predicate, adding functor, etc.).
__f Functor to process an element with __op (depends on desired
functionality, e. g. for std::for_each(), ...).
__r Functor to add a single __result to the already processed
elements (depends on functionality).
__base Base value for reduction.
__output Pointer to position where final result is written to
__bound Maximum number of elements processed (e. g. for
std::count_n()).
Returns:
User-supplied functor (that may contain a part of the
result).
Definition at line 67 of file omp_loop.h.
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:__begin Begin iterator of element sequence.
__end End iterator of element sequence.
__o User-supplied functor (comparator, predicate, adding functor, ...).
__f Functor to process an element with __op (depends on desired
functionality, e. g. for std::for_each(), ...).
__r Functor to add a single __result to the already processed
__elements (depends on functionality).
__base Base value for reduction.
__output Pointer to position where final result is written to
__bound Maximum number of elements processed (e. g. for
std::count_n()).
Returns:
User-supplied functor (that may contain a part of the
result).
Definition at line 66 of file omp_loop_static.h.
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:__begin Begin iterator of element sequence.
__end End iterator of element sequence.
__op User-supplied functor (comparator, predicate, adding functor, ...).
__f Functor to process an element with __op (depends on desired
functionality, e. g. for std::for_each(), ...).
__r Functor to add a single __result to the already processed
elements (depends on functionality).
__base Base value for reduction.
__output Pointer to position where final result is written to
__bound Maximum number of elements processed (e. g. for
std::count_n()).
Returns:
User-supplied functor (that may contain a part of the
result).
Definition at line 99 of file workstealing.h.
References __gnu_debug::__base(), __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:__begin Begin iterator of sequence.
__end End iterator of sequence.
__comp Comparator.
Returns:
true if sorted, false otherwise.
Definition at line 51 of file checkers.h.
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:__a First iterator.
__b Second iterator.
__c Third iterator.
__comp Comparator.
Definition at line 398 of file parallel/base.h.
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence.
__end2 End iterator of second sequence.
__target Target begin iterator.
__max_length Maximum number of elements to merge.
__comp Comparator.
Returns:
Output end iterator.
Definition at line 171 of file merge.h.
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence.
__end2 End iterator of second sequence.
__target Target begin iterator.
__max_length Maximum number of elements to merge.
__comp Comparator.
Returns:
Output end iterator.
Definition at line 105 of file merge.h.
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence.
__end2 End iterator of second sequence.
__target Target begin iterator.
__max_length Maximum number of elements to merge.
__comp Comparator.
Returns:
Output end iterator.
Definition at line 57 of file merge.h.
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence.
__end2 End iterator of second sequence.
__target Target begin iterator.
__max_length Maximum number of elements to merge.
__comp Comparator.
Returns:
Output end iterator.
Definition at line 195 of file merge.h.
References __merge_advance().
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence.
__end2 End iterator of second sequence.
__target Target begin iterator.
__max_length Maximum number of elements to merge.
__comp Comparator.
Returns:
Output end iterator.
Definition at line 223 of file merge.h.
References std::make_pair(), multiway_merge_exact_splitting(), and
parallel_multiway_merge().
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:__begin Begin iterator of input sequence.
__nth _Iterator of element that must be in position afterwards.
__end End iterator of input sequence.
__comp Comparator.
Definition at line 332 of file partition.h.
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:__begin Begin iterator of input sequence.
__middle Sort until this position.
__end End iterator of input sequence.
__comp Comparator.
Definition at line 422 of file partition.h.
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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__result Begin iterator of output sequence.
__bin_op Associative binary function.
Returns:
End iterator of output sequence.
Definition at line 205 of file partial_sum.h.
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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__result Begin iterator of output sequence.
__bin_op Associative binary function.
__value Start value. Must be passed since the neutral element is unknown
in general.
Returns:
End iterator of output sequence.
Definition at line 58 of file partial_sum.h.
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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__result Begin iterator of output sequence.
__bin_op Associative binary function.
__n Length of sequence.
Returns:
End iterator of output sequence.
Definition at line 89 of file partial_sum.h.
References __equally_split(), __parallel_partial_sum_basecase(),
std::accumulate(), __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:__begin Begin iterator of input sequence to split.
__end End iterator of input sequence to split.
__pred Partition predicate, possibly including some kind of pivot.
__num_threads Maximum number of threads to use for this task.
Returns:
Number of elements not fulfilling the predicate.
Definition at line 56 of file partition.h.
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:__begin Begin iterator of sequence.
__end End iterator of sequence.
__rng Random number generator to use.
Definition at line 522 of file random_shuffle.h.
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:__begin Begin iterator of sequence.
__end End iterator of sequence.
__n Length of sequence.
__num_threads Number of threads to use.
__rng Random number generator to use.
Definition at line 265 of file random_shuffle.h.
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::max(), 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:__pus Array of thread-local data records.
Definition at line 122 of file random_shuffle.h.
References __random_number_pow2(),
__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, 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, multiway_mergesort_tag__parallelism) [inline]¶
Choose multiway mergesort, splitting variant at run-time, for parallel sorting. Parameters:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 75 of file sort.h.
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, multiway_mergesort_exact_tag__parallelism) [inline]¶
Choose multiway mergesort with exact splitting, for parallel sorting. Parameters:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 99 of file sort.h.
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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 120 of file sort.h.
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, quicksort_tag__parallelism) [inline]¶
Choose quicksort for parallel sorting. Parameters:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 140 of file sort.h.
References __gnu_parallel::parallel_tag::__get_num_threads(),
__parallel_sort_qs(), and _GLIBCXX_CALL.
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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 161 of file sort.h.
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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 183 of file sort.h.
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, parallel_tag__parallelism) [inline]¶
Choose a parallel sorting algorithm. Parameters:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__comp Comparator.
Template Parameters:
__stable Sort stable.
Definition at line 203 of file sort.h.
References __gnu_parallel::parallel_tag::__get_num_threads(),
__parallel_sort_qs(), __parallel_sort_qsb(), _GLIBCXX_CALL, and
__gnu_parallel::_Settings::get().
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:__begin Begin iterator of input sequence.
__end End iterator input sequence, ignored.
__comp Comparator.
__num_threads Number of threads that are allowed to work on this
part.
Definition at line 154 of file quicksort.h.
References __parallel_sort_qs_conquer(), and _GLIBCXX_CALL.
Referenced by __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:__begin Begin iterator of subsequence.
__end End iterator of subsequence.
__comp Comparator.
__num_threads Number of threads that are allowed to work on this
part.
Definition at line 101 of file quicksort.h.
References __parallel_sort_qs_divide(), and __gnu_parallel::_Settings::get().
Referenced by __parallel_sort_qs().
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:__begin Begin iterator of subsequence.
__end End iterator of subsequence.
__comp Comparator.
__pivot_rank Desired __rank of the pivot.
__num_samples Choose pivot from that many samples.
__num_threads Number of threads that are allowed to work on this
part.
Definition at line 51 of file quicksort.h.
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:__begin Begin iterator of sequence.
__end End iterator of sequence.
__comp Comparator.
__num_threads Number of threads that are allowed to work on this
part.
Definition at line 430 of file balanced_quicksort.h.
References __qsb_conquer(), __rd_log2(), _GLIBCXX_CALL,
__gnu_parallel::_QSBThreadLocal< _RAIter >::_M_elements_leftover, and
std::make_pair().
Referenced by __parallel_sort().
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:__first Begin iterator of input sequence.
__last End iterator of input sequence.
__result Begin iterator of result __sequence.
__binary_pred Equality predicate.
Returns:
End iterator of result __sequence.
Definition at line 50 of file unique_copy.h.
References __equally_split(), and _GLIBCXX_CALL.
Referenced by __parallel_unique_copy().
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:__first Begin iterator of input sequence.
__last End iterator of input sequence.
__result Begin iterator of result __sequence.
Returns:
End iterator of result __sequence.
Definition at line 186 of file unique_copy.h.
References __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:__tls Array of thread-local storages.
__begin Begin iterator of subsequence.
__end End iterator of subsequence.
__comp Comparator.
__iam Number of the thread processing this function.
__num_threads Number of threads that are allowed to work on this
part.
Definition at line 171 of file balanced_quicksort.h.
References __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().
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:__begin Begin iterator of subsequence.
__end End iterator of subsequence.
__comp Comparator.
__num_threads Number of threads that are allowed to work on this
part.
Precondition:
(__end-__begin)>=1
Definition at line 100 of file balanced_quicksort.h.
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:__tls Array of thread-local storages.
__comp Comparator.
__iam Number of the thread processing this function.
Definition at line 247 of file balanced_quicksort.h.
References __yield(), _GLIBCXX_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(), std::make_pair(), 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:__logp Logarithm (basis 2) of the upper range
__bound.
__rng Random number generator to use.
Definition at line 115 of file random_shuffle.h.
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:__n Argument.
Returns:
Returns 0 for any argument <1.
Definition at line 102 of file parallel/base.h.
Referenced by __parallel_random_shuffle_drs(), __parallel_sort_qsb(),
__round_up_to_pow2(), __sequential_random_shuffle(),
__gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_LoserTreeBase(),
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:__x _Integer to round up
Definition at line 248 of file random_shuffle.h.
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:__begin1 Begin iterator of first sequence.
__end1 End iterator of first sequence.
__begin2 Begin iterator of second sequence.
__end2 End iterator of second sequence.
__pred Find predicate.
Returns:
Place of finding in first sequences.
Definition at line 81 of file search.h.
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:__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, possibly larger than the number of
elements available.
__sentinel The sequences have __a __sentinel element.
Returns:
End iterator of output sequence.
Definition at line 920 of file multiway_merge.h.
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:__begin Begin iterator of sequence.
__end End iterator of sequence.
__rng Random number generator to use.
Definition at line 410 of file random_shuffle.h.
References __random_number_pow2(), __rd_log2(), __round_up_to_pow2(),
__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().
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:__os_starts Start positions worked on
(oversampled).
__count_to_two Counts up to 2.
__range_length Current length of a chunk.
Definition at line 70 of file list_partition.h.
References std::vector< _Tp, _Alloc >::size().
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:__os_starts Start positions worked on
(oversampled).
__count_to_two Counts up to 2.
__range_length Current length of a chunk.
__make_twice Whether the __os_starts is allowed to be grown or not
Definition at line 50 of file list_partition.h.
References __shrink(), std::vector< _Tp, _Alloc >::resize(), and
std::vector< _Tp, _Alloc >::size().
Referenced by list_partition().
void __gnu_parallel::__yield () [inline]¶
Yield control to another thread, without waiting for the end of the time slice. Definition at line 121 of file parallel/compatibility.h. 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:__begin Begin iterator of input sequence.
__end End iterator of input sequence.
__starts Start iterators for the resulting parts, dimension
__num_parts+1. For convenience, __starts [__num_parts] contains the end
iterator of the sequence.
__lengths Length of the resulting parts.
__num_parts Number of parts to split the sequence into.
__f Functor to be applied to each element by traversing __it
__oversampling Oversampling factor. If 0, then the partitions will differ
in at most {{__end} - {__begin}} __elements. Otherwise, the ratio between the
longest and the shortest part is bounded by 1/({__oversampling} {num})
Returns:
Length of the whole sequence.
Definition at line 101 of file list_partition.h.
References __shrink_and_double(), and std::vector< _Tp, _Alloc >::size().
template<typename _Tp > const _Tp& __gnu_parallel::max (const _Tp &__a, const _Tp &__b) [inline]¶
Equivalent to std::max. Definition at line 150 of file parallel/base.h.template<typename _Tp > const _Tp& __gnu_parallel::min (const _Tp &__a, const _Tp &__b) [inline]¶
Equivalent to std::min. Definition at line 144 of file parallel/base.h. 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:__begin_seqs Begin of the sequence of iterator
pairs.
__end_seqs End of the sequence of iterator pairs.
__rank The global rank to partition at.
__begin_offsets A random-access __sequence __begin where the __result
will be stored in. Each element of the sequence is an iterator that points to
the first element on the greater part of the respective __sequence.
__comp The ordering functor, defaults to std::less<_Tp>.
Definition at line 122 of file multiseq_selection.h.
References __rd_log2(), _GLIBCXX_CALL, std::vector< _Tp, _Alloc
>::begin(), std::distance(), std::priority_queue< _Tp, _Sequence,
_Compare >::empty(), std::vector< _Tp, _Alloc >::end(),
std::make_pair(), std::max(), std::min(), std::priority_queue< _Tp,
_Sequence, _Compare >::pop(), std::priority_queue< _Tp, _Sequence,
_Compare >::push(), std::vector< _Tp, _Alloc >::push_back(), and
std::priority_queue< _Tp, _Sequence, _Compare >::top().
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:__begin_seqs Begin of the sequence of iterator
pairs.
__end_seqs End of the sequence of iterator pairs.
__rank The global rank to partition at.
__offset The rank of the selected element in the global subsequence of
elements equal to the selected element. If the selected element is unique,
this number is 0.
__comp The ordering functor, defaults to std::less.
Definition at line 388 of file multiseq_selection.h.
References __rd_log2(), __round_up_to_pow2(), _GLIBCXX_CALL, std::vector<
_Tp, _Alloc >::begin(), std::distance(), std::priority_queue< _Tp,
_Sequence, _Compare >::empty(), std::vector< _Tp, _Alloc >::end(),
std::make_pair(), std::max(), std::min(), std::priority_queue< _Tp,
_Sequence, _Compare >::pop(), std::priority_queue< _Tp, _Sequence,
_Compare >::push(), std::vector< _Tp, _Alloc >::push_back(), and
std::priority_queue< _Tp, _Sequence, _Compare >::top().
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
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:
stable_multiway_merge
Precondition:
All input sequences must be sorted.
Target must provide enough space to merge out length elements or the number of
elements in all sequences, whichever is smaller.
Postcondition:
[__target, return __value) contains merged __elements
from the input sequences.
return __value - __target = min(__length, number of elements in all
sequences).
Template Parameters:
_RAIterPairIterator iterator over sequence of
pairs of iterators
_RAIterOut iterator over target sequence
_DifferenceTp difference type for the sequence
_Compare strict weak ordering type to compare elements in sequences
Parameters:
__seqs_begin __begin of sequence __sequence
__seqs_end _M_end of sequence __sequence
__target target sequence to merge to.
__comp strict weak ordering to use for element comparison.
__length Maximum length to merge, possibly larger than the number of
elements available.
Returns:
_M_end iterator of output sequence
Definition at line 1418 of file multiway_merge.h.
References __sequential_multiway_merge(), and _GLIBCXX_CALL.
template<template< typename RAI, typename C > 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:__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, less equal than the total number of
elements available.
Returns:
End iterator of output sequence.
Definition at line 241 of file multiway_merge.h.
References _GLIBCXX_CALL.
template<template< typename RAI, typename C > 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:__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, less equal than the total number of
elements available.
Returns:
End iterator of output sequence.
Definition at line 360 of file multiway_merge.h.
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. Definition at line 1120 of file multiway_merge.h. References __equally_split(), _GLIBCXX_PARALLEL_LENGTH, std::vector< _Tp, _Alloc >::begin(), std::vector< _Tp, _Alloc >::end(), multiseq_partition(), and std::vector< _Tp, _Alloc >::resize(). 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:__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, less equal than the total number of
elements available.
Returns:
End iterator of output sequence.
Definition at line 491 of file multiway_merge.h.
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:UnguardedLoserTree _Loser Tree variant to use for
the unguarded merging.
Parameters:
__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, less equal than the total number of
elements available.
Returns:
End iterator of output sequence.
Definition at line 662 of file multiway_merge.h.
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:No input will run out of elements during the merge.
Parameters:
__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, less equal than the total number of
elements available.
Returns:
End iterator of output sequence.
Definition at line 574 of file multiway_merge.h.
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. Definition at line 1035 of file multiway_merge.h. 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
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:
All input sequences must be sorted.
Target must provide enough space to merge out length elements or the number of
elements in all sequences, whichever is smaller.
For each __i, __seqs_begin[__i].second must be the end marker of the sequence,
but also reference the one more __sentinel element.
Postcondition:
[__target, return __value) contains merged __elements
from the input sequences.
return __value - __target = min(__length, number of elements in all
sequences).
See also:
stable_multiway_merge_sentinels
Template Parameters:
_RAIterPairIterator iterator over sequence of
pairs of iterators
_RAIterOut iterator over target sequence
_DifferenceTp difference type for the sequence
_Compare strict weak ordering type to compare elements in sequences
Parameters:
__seqs_begin __begin of sequence __sequence
__seqs_end _M_end of sequence __sequence
__target target sequence to merge to.
__comp strict weak ordering to use for element comparison.
__length Maximum length to merge, possibly larger than the number of
elements available.
Returns:
_M_end iterator of output sequence
Definition at line 1782 of file multiway_merge.h.
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:_Splitter functor to split input (either __exact
or sampling based)
__stable Stable merging incurs a performance penalty.
__sentinel Ignored.
Parameters:
__seqs_begin Begin iterator of iterator pair input
sequence.
__seqs_end End iterator of iterator pair input sequence.
__target Begin iterator of output sequence.
__comp Comparator.
__length Maximum length to merge, possibly larger than the number of
elements available.
Returns:
End iterator of output sequence.
Definition at line 1225 of file multiway_merge.h.
References __is_sorted(), _GLIBCXX_CALL, _GLIBCXX_PARALLEL_LENGTH,
__gnu_parallel::_Settings::get(), std::make_pair(), 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:__begin Begin iterator of sequence.
__end End iterator of sequence.
__comp Comparator.
__num_threads Number of threads to use.
Definition at line 395 of file multiway_mergesort.h.
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:__sd Pointer to algorithm data.
__comp Comparator.
Definition at line 308 of file multiway_mergesort.h.
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(), std::make_pair(),
__gnu_parallel::_Settings::sort_mwms_oversampling, and
std::uninitialized_copy().
Variable Documentation¶
const int __gnu_parallel::_CASable_bits [static]¶
Number of bits of _CASable. Definition at line 130 of file types.h. Referenced by __decode2(), and __encode2().const _CASable __gnu_parallel::_CASable_mask [static]¶
_CASable with the right half of bits set to 1. Definition at line 133 of file types.h. Referenced by __decode2().Author¶
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