__gnu_parallel Namespace Reference

GNU parallel code for public use. More...

Classes

Typedefs

Enumerations

Functions

Variables

Detailed Description

GNU parallel code for public use.

Typedef Documentation

typedef unsigned short __gnu_parallel::bin_index

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 short __gnu_parallel::int16

Integer Types.

16-bit signed integer.

Definition at line 114 of file types.h.

typedef int __gnu_parallel::int32

32-bit signed integer.

Definition at line 120 of file types.h.

typedef long long __gnu_parallel::int64

64-bit signed integer.

Definition at line 126 of file types.h.

typedef int64 __gnu_parallel::lcas_t

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

Definition at line 145 of file types.h.

typedef uint64 __gnu_parallel::sequence_index_t

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

Definition at line 135 of file types.h.

typedef uint16 __gnu_parallel::thread_index_t

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

Definition at line 141 of file types.h.

typedef unsigned short __gnu_parallel::uint16

16-bit unsigned integer.

Definition at line 117 of file types.h.

typedef unsigned int __gnu_parallel::uint32

32-bit unsigned integer.

Definition at line 123 of file types.h.

typedef unsigned long long __gnu_parallel::uint64

64-bit unsigned integer.

Definition at line 129 of file types.h.

Enumeration Type Documentation

enum __gnu_parallel::_AlgorithmStrategy

Strategies for run-time algorithm selection:.

Definition at line 65 of file types.h.

enum __gnu_parallel::_FindAlgorithm

Find algorithms:.

Definition at line 104 of file types.h.

enum __gnu_parallel::_MultiwayMergeAlgorithm

Merging algorithms:.

Definition at line 83 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.

Definition at line 42 of file types.h.

enum __gnu_parallel::_PartialSumAlgorithm

Partial sum algorithms: recursive, linear.

Definition at line 89 of file types.h.

enum __gnu_parallel::_SortAlgorithm

Sorting algorithms:.

Definition at line 74 of file types.h.

enum __gnu_parallel::_SplittingAlgorithm

Sorting/merging algorithms: sampling, exact.

Definition at line 96 of file types.h.

Function Documentation

template<typename Size >
Size __gnu_parallel::__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 105 of file base.h.

Referenced by __gnu_parallel::LoserTreeBase< T, Comparator >::LoserTreeBase(), multiseq_partition(), multiseq_selection(), parallel_random_shuffle_drs(), round_up_to_pow2(), and sequential_random_shuffle().

template<typename RandomAccessIterator , typename _DifferenceTp >
void __gnu_parallel::calc_borders ( RandomAccessIterator  elements,
_DifferenceTp  length,
_DifferenceTp *  off 
) [inline]

Precalculate advances for Knuth-Morris-Pratt algorithm.

Parameters:
elements Begin iterator of sequence to search for.
length Length of sequence to search for.
advances Returned offsets.

Definition at line 52 of file search.h.

Referenced by search_template().

template<typename T >
bool __gnu_parallel::compare_and_swap ( volatile T *  ptr,
T  comparand,
T  replacement 
) [inline]

Compare *ptr and comparand. If equal, let *ptr=replacement and return true, return false otherwise.

Implementation is heavily platform-dependent.

Parameters:
ptr Pointer to signed integer.
comparand Compare value.
replacement Replacement value.

Definition at line 327 of file parallel/compatibility.h.

References compare_and_swap_32(), and compare_and_swap_64().

Referenced by __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::pop_back(), and __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::pop_front().

bool __gnu_parallel::compare_and_swap_32 ( volatile int32 *  ptr,
int32  comparand,
int32  replacement 
) [inline]

Compare *ptr and comparand. If equal, let *ptr=replacement and return true, return false otherwise.

Implementation is heavily platform-dependent.

Parameters:
ptr Pointer to 32-bit signed integer.
comparand Compare value.
replacement Replacement value.

Definition at line 235 of file parallel/compatibility.h.

Referenced by compare_and_swap().

bool __gnu_parallel::compare_and_swap_64 ( volatile int64 *  ptr,
int64  comparand,
int64  replacement 
) [inline]

Compare *ptr and comparand. If equal, let *ptr=replacement and return true, return false otherwise.

Implementation is heavily platform-dependent.

Parameters:
ptr Pointer to 64-bit signed integer.
comparand Compare value.
replacement Replacement value.

Definition at line 275 of file parallel/compatibility.h.

Referenced by compare_and_swap().

void __gnu_parallel::decode2 ( lcas_t  x,
int &  a,
int &  b 
) [inline]

Decode two integers from one __gnu_parallel::lcas_t.

Parameters:
x __gnu_parallel::lcas_t to decode integers from.
a First integer, to be decoded from the most-significant lcas_t_bits/2 bits of x.
b Second integer, to be encoded in the least-significant lcas_t_bits/2 bits of x.
See also:
encode2

Definition at line 136 of file base.h.

References lcas_t_bits, and lcas_t_mask.

Referenced by __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::pop_back(), __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::pop_front(), and __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::push_front().

template<typename RandomAccessIterator , typename _DifferenceTp >
void __gnu_parallel::determine_samples ( PMWMSSortingData< RandomAccessIterator > *  sd,
_DifferenceTp  num_samples 
) [inline]

Select samples from a sequence.

Parameters:
sd Pointer to algorithm data. Result will be placed in sd->samples.
num_samples Number of samples to select.

Definition at line 98 of file multiway_mergesort.h.

References equally_split(), __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::samples, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::source, and __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::starts.

lcas_t __gnu_parallel::encode2 ( int  a,
int  b 
) [inline]

Encode two integers into one __gnu_parallel::lcas_t.

Parameters:
a First integer, to be encoded in the most-significant lcas_t_bits/2 bits.
b Second integer, to be encoded in the least-significant lcas_t_bits/2 bits.
Returns:
__gnu_parallel::lcas_t value encoding a and b.
See also:
decode2

Definition at line 122 of file base.h.

References lcas_t_bits.

Referenced by __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::pop_back(), __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::pop_front(), __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::push_front(), and __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::RestrictedBoundedConcurrentQueue().

template<typename difference_type , typename OutputIterator >
OutputIterator __gnu_parallel::equally_split ( difference_type  n,
thread_index_t  num_threads,
OutputIterator  s 
) [inline]

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(), multiway_merge_exact_splitting(), parallel_partial_sum_linear(), parallel_unique_copy(), and search_template().

template<typename difference_type >
difference_type __gnu_parallel::equally_split_point ( difference_type  n,
thread_index_t  num_threads,
thread_index_t  thread_no 
) [inline]

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
Returns:
_SplittingAlgorithm point

Definition at line 73 of file equally_split.h.

Referenced by for_each_template_random_access_ed().

template<typename T >
T __gnu_parallel::fetch_and_add ( volatile T *  ptr,
T  addend 
) [inline]

Add a value to a variable, atomically.

Implementation is heavily platform-dependent.

Parameters:
ptr Pointer to a signed integer.
addend Value to add.

Definition at line 185 of file parallel/compatibility.h.

References fetch_and_add_32(), and fetch_and_add_64().

Referenced by __gnu_parallel::RestrictedBoundedConcurrentQueue< Piece >::push_front().

int32 __gnu_parallel::fetch_and_add_32 ( volatile int32 *  ptr,
int32  addend 
) [inline]

Add a value to a variable, atomically.

Implementation is heavily platform-dependent.

Parameters:
ptr Pointer to a 32-bit signed integer.
addend Value to add.

Definition at line 95 of file parallel/compatibility.h.

Referenced by fetch_and_add().

int64 __gnu_parallel::fetch_and_add_64 ( volatile int64 *  ptr,
int64  addend 
) [inline]

Add a value to a variable, atomically.

Implementation is heavily platform-dependent.

Parameters:
ptr Pointer to a 64-bit signed integer.
addend Value to add.

Definition at line 134 of file parallel/compatibility.h.

Referenced by fetch_and_add().

template<typename RandomAccessIterator1 , typename RandomAccessIterator2 , typename Pred , typename Selector >
std::pair<RandomAccessIterator1, RandomAccessIterator2> __gnu_parallel::find_template ( RandomAccessIterator1  begin1,
RandomAccessIterator1  end1,
RandomAccessIterator2  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().

template<typename InputIterator , typename UserOp , typename Functionality , typename Red , typename Result >
UserOp __gnu_parallel::for_each_template_random_access ( InputIterator  begin,
InputIterator  end,
UserOp  user_op,
Functionality &  functionality,
Red  reduction,
Result  reduction_start,
Result &  output,
typename std::iterator_traits< InputIterator >::difference_type  bound,
_Parallelism  parallelism_tag 
) [inline]

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 RandomAccessIterator , typename Op , typename Fu , typename Red , typename Result >
Op __gnu_parallel::for_each_template_random_access_ed ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Op  o,
Fu &  f,
Red  r,
Result  base,
Result &  output,
typename std::iterator_traits< RandomAccessIterator >::difference_type  bound 
) [inline]

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 68 of file par_loop.h.

References equally_split_point().

Referenced by for_each_template_random_access().

template<typename RandomAccessIterator , typename Op , typename Fu , typename Red , typename Result >
Op __gnu_parallel::for_each_template_random_access_omp_loop ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Op  o,
Fu &  f,
Red  r,
Result  base,
Result &  output,
typename std::iterator_traits< RandomAccessIterator >::difference_type  bound 
) [inline]

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 RandomAccessIterator , typename Op , typename Fu , typename Red , typename Result >
Op __gnu_parallel::for_each_template_random_access_omp_loop_static ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Op  o,
Fu &  f,
Red  r,
Result  base,
Result &  output,
typename std::iterator_traits< RandomAccessIterator >::difference_type  bound 
) [inline]

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 67 of file omp_loop_static.h.

template<typename RandomAccessIterator , typename Op , typename Fu , typename Red , typename Result >
Op __gnu_parallel::for_each_template_random_access_workstealing ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Op  op,
Fu &  f,
Red  r,
Result  base,
Result &  output,
typename std::iterator_traits< RandomAccessIterator >::difference_type  bound 
) [inline]

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 _GLIBCXX_CALL, __gnu_parallel::_Settings::cache_line_size, __gnu_parallel::Job< _DifferenceTp >::first, __gnu_parallel::_Settings::get(), __gnu_parallel::Job< _DifferenceTp >::last, __gnu_parallel::Job< _DifferenceTp >::load, min(), __gnu_parallel::_Settings::workstealing_chunk_size, and yield().

Referenced by for_each_template_random_access().

template<typename InputIterator , typename Comparator >
bool __gnu_parallel::is_sorted ( InputIterator  begin,
InputIterator  end,
Comparator  comp = std::less<typename std::iterator_traits<InputIterator>:: value_type>() 
) [inline]

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 multiway_merge_loser_tree_sentinel(), parallel_multiway_merge(), and sequential_multiway_merge().

template<typename InputIterator , typename Comparator >
bool __gnu_parallel::is_sorted_failure ( InputIterator  begin,
InputIterator  end,
InputIterator &  first_failure,
Comparator  comp = std::less<typename std::iterator_traits<InputIterator>:: value_type>() 
) [inline]

Check whether [begin, end) is sorted according to comp. Prints the position in case an unordered pair is found.

Parameters:
begin Begin iterator of sequence.
end End iterator of sequence.
first_failure The first failure is returned in this variable.
comp Comparator.
Returns:
true if sorted, false otherwise.

Definition at line 89 of file checkers.h.

template<typename InputIterator , typename Comparator >
bool __gnu_parallel::is_sorted_print_failures ( InputIterator  begin,
InputIterator  end,
Comparator  comp = std::less<typename std::iterator_traits <InputIterator>::value_type>() 
) [inline]

Check whether [begin, end) is sorted according to comp. Prints all unordered pair, including the surrounding two elements.

Parameters:
begin Begin iterator of sequence.
end End iterator of sequence.
comp Comparator.
Returns:
true if sorted, false otherwise.

Definition at line 129 of file checkers.h.

template<typename InputIterator , typename FunctorType >
size_t __gnu_parallel::list_partition ( const InputIterator  begin,
const InputIterator  end,
InputIterator *  starts,
size_t *  lengths,
const int  num_parts,
FunctorType &  f,
int  oversampling = 0 
) [inline]

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 $ \sqrt{\mathrm{end} - \mathrm{begin}} $ elements. Otherwise, the ratio between the longest and the shortest part is bounded by $ 1/(\mathrm{oversampling} \cdot \mathrm{num\_parts}) $.
Returns:
Length of the whole sequence.

Definition at line 100 of file list_partition.h.

References shrink_and_double(), and std::vector< _Tp, _Alloc >::size().

template<typename T >
const T& __gnu_parallel::max ( const T &  a,
const T &  b 
) [inline]

Equivalent to std::max.

Definition at line 151 of file base.h.

Referenced by std::_Deque_base< _Tp, _Alloc >::_M_initialize_map(), multiseq_partition(), and multiseq_selection().

template<typename RandomAccessIterator , typename Comparator >
RandomAccessIterator __gnu_parallel::median_of_three_iterators ( RandomAccessIterator  a,
RandomAccessIterator  b,
RandomAccessIterator  c,
Comparator &  comp 
) [inline]

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 443 of file base.h.

Referenced by qsb_divide().

template<typename RandomAccessIterator1 , typename RandomAccessIterator2 , typename OutputIterator , typename _DifferenceTp , typename Comparator >
OutputIterator __gnu_parallel::merge_advance ( RandomAccessIterator1 &  begin1,
RandomAccessIterator1  end1,
RandomAccessIterator2 &  begin2,
RandomAccessIterator2  end2,
OutputIterator  target,
_DifferenceTp  max_length,
Comparator  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 174 of file merge.h.

References _GLIBCXX_CALL, and merge_advance_movc().

Referenced by parallel_merge_advance(), and sequential_multiway_merge().

template<typename RandomAccessIterator1 , typename RandomAccessIterator2 , typename OutputIterator , typename _DifferenceTp , typename Comparator >
OutputIterator __gnu_parallel::merge_advance_movc ( RandomAccessIterator1 &  begin1,
RandomAccessIterator1  end1,
RandomAccessIterator2 &  begin2,
RandomAccessIterator2  end2,
OutputIterator  target,
_DifferenceTp  max_length,
Comparator  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. 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 106 of file merge.h.

Referenced by merge_advance().

template<typename RandomAccessIterator1 , typename RandomAccessIterator2 , typename OutputIterator , typename _DifferenceTp , typename Comparator >
OutputIterator __gnu_parallel::merge_advance_usual ( RandomAccessIterator1 &  begin1,
RandomAccessIterator1  end1,
RandomAccessIterator2 &  begin2,
RandomAccessIterator2  end2,
OutputIterator  target,
_DifferenceTp  max_length,
Comparator  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.

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 T >
const T& __gnu_parallel::min ( const T &  a,
const T &  b 
) [inline]

Equivalent to std::min.

Definition at line 145 of file base.h.

Referenced by __gnu_cxx::__versa_string< _CharT, _Traits, _Alloc, _Base >::compare(), for_each_template_random_access_workstealing(), multiseq_partition(), multiseq_selection(), parallel_sort_qs_divide(), __gnu_cxx::random_sample_n(), __gnu_cxx::__versa_string< _CharT, _Traits, _Alloc, _Base >::rfind(), search_template(), and std::basic_filebuf< _CharT, _Traits >::xsputn().

template<typename RanSeqs , typename RankType , typename RankIterator , typename Comparator >
void __gnu_parallel::multiseq_partition ( RanSeqs  begin_seqs,
RanSeqs  end_seqs,
RankType  rank,
RankIterator  begin_offsets,
Comparator  comp = std::less< typename std::iterator_traits<typename std::iterator_traits<RanSeqs>::value_type:: first_type>::value_type>() 
) [inline]

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<T>.

Definition at line 123 of file multiseq_selection.h.

References __log2(), _GLIBCXX_CALL, std::vector< _Tp, _Alloc >::begin(), std::distance(), std::priority_queue< _Tp, _Sequence, _Compare >::empty(), std::vector< _Tp, _Alloc >::end(), max(), 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 T , typename RanSeqs , typename RankType , typename Comparator >
T __gnu_parallel::multiseq_selection ( RanSeqs  begin_seqs,
RanSeqs  end_seqs,
RankType  rank,
RankType &  offset,
Comparator  comp = std::less<T>() 
) [inline]

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 384 of file multiseq_selection.h.

References __log2(), _GLIBCXX_CALL, std::vector< _Tp, _Alloc >::begin(), std::distance(), std::priority_queue< _Tp, _Sequence, _Compare >::empty(), std::vector< _Tp, _Alloc >::end(), std::lower_bound(), max(), 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 RandomAccessIteratorPairIterator , typename RandomAccessIteratorOut , typename _DifferenceTp , typename Comparator >
RandomAccessIteratorOut __gnu_parallel::multiway_merge ( RandomAccessIteratorPairIterator  seqs_begin,
RandomAccessIteratorPairIterator  seqs_end,
RandomAccessIteratorOut  target,
_DifferenceTp  length,
Comparator  comp,
__gnu_parallel::sequential_tag   
) [inline]

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 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:
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).

Parameters:
RandomAccessIteratorPairIterator iterator over sequence of pairs of iterators
RandomAccessIteratorOut iterator over target sequence
_DifferenceTp difference type for the sequence
Comparator strict weak ordering type to compare elements in sequences
seqs_begin begin of sequence sequence
seqs_end 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:
end iterator of output sequence

Definition at line 1482 of file multiway_merge.h.

References _GLIBCXX_CALL, and sequential_multiway_merge().

template<template< typename RAI, typename C > class iterator, typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Comparator >
RandomAccessIterator3 __gnu_parallel::multiway_merge_3_variant ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
_DifferenceTp  length,
Comparator  comp 
) [inline]

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 out 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 out 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 290 of file multiway_merge.h.

References _GLIBCXX_CALL.

template<template< typename RAI, typename C > class iterator, typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Comparator >
RandomAccessIterator3 __gnu_parallel::multiway_merge_4_variant ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
_DifferenceTp  length,
Comparator  comp 
) [inline]

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 out 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 out 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 410 of file multiway_merge.h.

References _GLIBCXX_CALL.

template<bool stable, typename RandomAccessIteratorIterator , typename Comparator , typename difference_type >
void __gnu_parallel::multiway_merge_exact_splitting ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
difference_type  length,
difference_type  total_length,
Comparator  comp,
std::vector< std::pair< difference_type, difference_type > > *  pieces 
) [inline]

Exact splitting for parallel multiway-merge routine.

None of the passed sequences may be empty.

Definition at line 1181 of file multiway_merge.h.

References _GLIBCXX_PARALLEL_LENGTH, std::vector< _Tp, _Alloc >::begin(), equally_split(), multiseq_partition(), and std::vector< _Tp, _Alloc >::resize().

Referenced by parallel_merge_advance().

template<typename LT , typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Comparator >
RandomAccessIterator3 __gnu_parallel::multiway_merge_loser_tree ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
_DifferenceTp  length,
Comparator  comp 
) [inline]

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 out 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 534 of file multiway_merge.h.

References _GLIBCXX_CALL, and _GLIBCXX_PARALLEL_LENGTH.

template<typename UnguardedLoserTree , typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Comparator >
RandomAccessIterator3 __gnu_parallel::multiway_merge_loser_tree_sentinel ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
const typename std::iterator_traits< typename std::iterator_traits< RandomAccessIteratorIterator >::value_type::first_type >::value_type &  sentinel,
_DifferenceTp  length,
Comparator  comp 
) [inline]

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

Parameters:
stable The value must the same as for the used LoserTrees.
UnguardedLoserTree Loser Tree variant to use for the unguarded merging.
GuardedLoserTree Loser Tree variant to use for the guarded merging.
seqs_begin Begin iterator of iterator pair input sequence.
seqs_end End iterator of iterator pair input sequence.
target Begin iterator out 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 705 of file multiway_merge.h.

References _GLIBCXX_CALL, is_sorted(), and multiway_merge_loser_tree_unguarded().

template<typename LT , typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Comparator >
RandomAccessIterator3 __gnu_parallel::multiway_merge_loser_tree_unguarded ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
const typename std::iterator_traits< typename std::iterator_traits< RandomAccessIteratorIterator >::value_type::first_type >::value_type &  sentinel,
_DifferenceTp  length,
Comparator  comp 
) [inline]

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 out 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 615 of file multiway_merge.h.

References _GLIBCXX_CALL.

Referenced by multiway_merge_loser_tree_sentinel().

template<bool stable, typename RandomAccessIteratorIterator , typename Comparator , typename difference_type >
void __gnu_parallel::multiway_merge_sampling_splitting ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
difference_type  length,
difference_type  total_length,
Comparator  comp,
std::vector< std::pair< difference_type, difference_type > > *  pieces 
) [inline]

Sampling based splitting for parallel multiway-merge routine.

Definition at line 1100 of file multiway_merge.h.

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

template<typename RandomAccessIteratorPairIterator , typename RandomAccessIteratorOut , typename _DifferenceTp , typename Comparator >
RandomAccessIteratorOut __gnu_parallel::multiway_merge_sentinels ( RandomAccessIteratorPairIterator  seqs_begin,
RandomAccessIteratorPairIterator  seqs_end,
RandomAccessIteratorOut  target,
_DifferenceTp  length,
Comparator  comp,
__gnu_parallel::sequential_tag   
) [inline]

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 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 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:
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
Parameters:
RandomAccessIteratorPairIterator iterator over sequence of pairs of iterators
RandomAccessIteratorOut iterator over target sequence
_DifferenceTp difference type for the sequence
Comparator strict weak ordering type to compare elements in sequences
seqs_begin begin of sequence sequence
seqs_end 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:
end iterator of output sequence

Definition at line 1854 of file multiway_merge.h.

References _GLIBCXX_CALL, and sequential_multiway_merge().

template<typename RandomAccessIterator , typename Comparator >
bool __gnu_parallel::operator< ( unguarded_iterator< RandomAccessIterator, Comparator > &  bi1,
unguarded_iterator< RandomAccessIterator, Comparator > &  bi2 
) [inline]

Compare two elements referenced by unguarded iterators.

Parameters:
bi1 First iterator.
bi2 Second iterator.
Returns:
True if less.

Definition at line 239 of file multiway_merge.h.

template<typename RandomAccessIterator , typename Comparator >
bool __gnu_parallel::operator< ( guarded_iterator< RandomAccessIterator, Comparator > &  bi1,
guarded_iterator< RandomAccessIterator, Comparator > &  bi2 
) [inline]

Compare two elements referenced by guarded iterators.

Parameters:
bi1 First iterator.
bi2 Second iterator.
Returns:
True if less.

Definition at line 144 of file multiway_merge.h.

template<typename RandomAccessIterator , typename Comparator >
bool __gnu_parallel::operator<= ( unguarded_iterator< RandomAccessIterator, Comparator > &  bi1,
unguarded_iterator< RandomAccessIterator, Comparator > &  bi2 
) [inline]

Compare two elements referenced by unguarded iterators.

Parameters:
bi1 First iterator.
bi2 Second iterator.
Returns:
True if less equal.

Definition at line 252 of file multiway_merge.h.

template<typename RandomAccessIterator , typename Comparator >
bool __gnu_parallel::operator<= ( guarded_iterator< RandomAccessIterator, Comparator > &  bi1,
guarded_iterator< RandomAccessIterator, Comparator > &  bi2 
) [inline]

Compare two elements referenced by guarded iterators.

Parameters:
bi1 First iterator.
bi2 Second iterator.
Returns:
True if less equal.

Definition at line 160 of file multiway_merge.h.

template<typename RandomAccessIterator1 , typename RandomAccessIterator3 , typename Comparator >
RandomAccessIterator3 __gnu_parallel::parallel_merge_advance ( RandomAccessIterator1 &  begin1,
RandomAccessIterator1  end1,
RandomAccessIterator1 &  begin2,
RandomAccessIterator1  end2,
RandomAccessIterator3  target,
typename std::iterator_traits< RandomAccessIterator1 >::difference_type  max_length,
Comparator  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 228 of file merge.h.

References multiway_merge_exact_splitting(), and parallel_multiway_merge().

template<typename RandomAccessIterator1 , typename RandomAccessIterator2 , typename RandomAccessIterator3 , typename Comparator >
RandomAccessIterator3 __gnu_parallel::parallel_merge_advance ( RandomAccessIterator1 &  begin1,
RandomAccessIterator1  end1,
RandomAccessIterator2 &  begin2,
RandomAccessIterator2  end2,
RandomAccessIterator3  target,
typename std::iterator_traits< RandomAccessIterator1 >::difference_type  max_length,
Comparator  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 198 of file merge.h.

References merge_advance().

template<bool stable, bool sentinels, typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Splitter , typename Comparator >
RandomAccessIterator3 __gnu_parallel::parallel_multiway_merge ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
Splitter  splitter,
_DifferenceTp  length,
Comparator  comp,
thread_index_t  num_threads 
) [inline]

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.

Parameters:
Splitter functor to split input (either exact or sampling based)
seqs_begin Begin iterator of iterator pair input sequence.
seqs_end End iterator of iterator pair input sequence.
target Begin iterator out output sequence.
comp Comparator.
length Maximum length to merge, possibly larger than the number of elements available.
stable Stable merging incurs a performance penalty.
sentinel Ignored.
Returns:
End iterator of output sequence.

Definition at line 1286 of file multiway_merge.h.

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

Referenced by parallel_merge_advance().

template<typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_nth_element ( RandomAccessIterator  begin,
RandomAccessIterator  nth,
RandomAccessIterator  end,
Comparator  comp 
) [inline]

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 330 of file partition.h.

References _GLIBCXX_CALL, __gnu_parallel::_Settings::get(), parallel_partition(), and __gnu_parallel::_Settings::partition_minimal_n.

Referenced by parallel_partial_sort().

template<typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_partial_sort ( RandomAccessIterator  begin,
RandomAccessIterator  middle,
RandomAccessIterator  end,
Comparator  comp 
) [inline]

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 417 of file partition.h.

References parallel_nth_element().

template<typename InputIterator , typename OutputIterator , typename BinaryOperation >
OutputIterator __gnu_parallel::parallel_partial_sum ( InputIterator  begin,
InputIterator  end,
OutputIterator  result,
BinaryOperation  bin_op 
) [inline]

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 196 of file partial_sum.h.

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

template<typename InputIterator , typename OutputIterator , typename BinaryOperation >
OutputIterator __gnu_parallel::parallel_partial_sum_basecase ( InputIterator  begin,
InputIterator  end,
OutputIterator  result,
BinaryOperation  bin_op,
typename std::iterator_traits< InputIterator >::value_type  value 
) [inline]

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 InputIterator , typename OutputIterator , typename BinaryOperation >
OutputIterator __gnu_parallel::parallel_partial_sum_linear ( InputIterator  begin,
InputIterator  end,
OutputIterator  result,
BinaryOperation  bin_op,
typename std::iterator_traits< InputIterator >::difference_type  n 
) [inline]

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.
num_threads Number of threads to use.
Returns:
End iterator of output sequence.

Definition at line 90 of file partial_sum.h.

References std::accumulate(), equally_split(), __gnu_parallel::_Settings::get(), parallel_partial_sum_basecase(), and __gnu_parallel::_Settings::partial_sum_dilation.

Referenced by parallel_partial_sum().

template<typename RandomAccessIterator , typename Predicate >
std::iterator_traits<RandomAccessIterator>::difference_type __gnu_parallel::parallel_partition ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Predicate  pred,
thread_index_t  num_threads 
) [inline]

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 55 of file partition.h.

References _GLIBCXX_CALL, _GLIBCXX_VOLATILE, __gnu_parallel::_Settings::get(), std::left(), __gnu_parallel::_Settings::partition_chunk_share, __gnu_parallel::_Settings::partition_chunk_size, std::right(), and std::swap_ranges().

Referenced by parallel_nth_element(), parallel_sort_qs_divide(), and qsb_divide().

template<typename RandomAccessIterator , typename RandomNumberGenerator >
void __gnu_parallel::parallel_random_shuffle ( RandomAccessIterator  begin,
RandomAccessIterator  end,
RandomNumberGenerator  rng = random_number() 
) [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 507 of file random_shuffle.h.

References parallel_random_shuffle_drs().

template<typename RandomAccessIterator , typename RandomNumberGenerator >
void __gnu_parallel::parallel_random_shuffle_drs ( RandomAccessIterator  begin,
RandomAccessIterator  end,
typename std::iterator_traits< RandomAccessIterator >::difference_type  n,
thread_index_t  num_threads,
RandomNumberGenerator &  rng 
) [inline]

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 258 of file random_shuffle.h.

References __log2(), _GLIBCXX_CALL, __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::bin_proc, __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::bins_begin, __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::bins_end, __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::dist, __gnu_parallel::_Settings::L2_cache_size, std::min(), __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::num_bins, __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::num_bits, __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::num_threads, parallel_random_shuffle_drs_pu(), round_up_to_pow2(), __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::sd, __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::seed, sequential_random_shuffle(), __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::starts, __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::temporaries, and __gnu_parallel::_Settings::TLB_size.

Referenced by parallel_random_shuffle().

template<typename RandomAccessIterator , typename RandomNumberGenerator >
void __gnu_parallel::parallel_random_shuffle_drs_pu ( DRSSorterPU< RandomAccessIterator, RandomNumberGenerator > *  pus  )  [inline]

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 __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::dist, __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::num_bins, __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::num_bits, __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::num_threads, random_number_pow2(), __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::sd, __gnu_parallel::DRSSorterPU< RandomAccessIterator, RandomNumberGenerator >::seed, and __gnu_parallel::DRandomShufflingGlobalData< RandomAccessIterator >::starts.

Referenced by parallel_random_shuffle_drs().

template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.
stable Sort stable.

Definition at line 196 of file sort.h.

References _GLIBCXX_CALL, __gnu_parallel::_Settings::get(), __gnu_parallel::parallel_tag::get_num_threads(), parallel_sort_qs(), parallel_sort_qsb(), and __gnu_parallel::_Settings::sort_algorithm.

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template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.

Definition at line 175 of file sort.h.

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

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template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.
stable Sort stable.

Definition at line 154 of file sort.h.

References _GLIBCXX_CALL, __gnu_parallel::parallel_tag::get_num_threads(), and parallel_sort_qsb().

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template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.

Definition at line 134 of file sort.h.

References _GLIBCXX_CALL, __gnu_parallel::parallel_tag::get_num_threads(), and parallel_sort_qs().

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template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.

Definition at line 116 of file sort.h.

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

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template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.

Definition at line 97 of file sort.h.

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

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template<bool stable, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  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.

Definition at line 74 of file sort.h.

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

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template<bool stable, bool exact, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort_mwms ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
thread_index_t  num_threads 
) [inline]

PMWMS main call.

Parameters:
begin Begin iterator of sequence.
end End iterator of sequence.
comp Comparator.
n Length of sequence.
num_threads Number of threads to use.

Definition at line 398 of file multiway_mergesort.h.

References _GLIBCXX_CALL, __gnu_parallel::_Settings::get(), __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::num_threads, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::offsets, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::pieces, std::vector< _Tp, _Alloc >::resize(), __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::samples, __gnu_parallel::_Settings::sort_mwms_oversampling, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::source, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::starts, and __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::temporary.

template<bool stable, bool exact, typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort_mwms_pu ( PMWMSSortingData< RandomAccessIterator > *  sd,
Comparator &  comp 
) [inline]

PMWMS code executed by each thread.

Parameters:
sd Pointer to algorithm data.
comp Comparator.

Definition at line 315 of file multiway_mergesort.h.

References std::vector< _Tp, _Alloc >::begin(), std::vector< _Tp, _Alloc >::end(), __gnu_parallel::_Settings::get(), __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::num_threads, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::pieces, __gnu_parallel::_Settings::sort_mwms_oversampling, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::source, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::starts, __gnu_parallel::PMWMSSortingData< RandomAccessIterator >::temporary, and std::uninitialized_copy().

template<typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort_qs ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
thread_index_t  num_threads 
) [inline]

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 157 of file quicksort.h.

References _GLIBCXX_CALL, and parallel_sort_qs_conquer().

Referenced by parallel_sort().

template<typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort_qs_conquer ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
thread_index_t  num_threads 
) [inline]

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 __gnu_parallel::_Settings::get(), and parallel_sort_qs_divide().

Referenced by parallel_sort_qs().

template<typename RandomAccessIterator , typename Comparator >
std::iterator_traits<RandomAccessIterator>::difference_type __gnu_parallel::parallel_sort_qs_divide ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
typename std::iterator_traits< RandomAccessIterator >::difference_type  pivot_rank,
typename std::iterator_traits< RandomAccessIterator >::difference_type  num_samples,
thread_index_t  num_threads 
) [inline]

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 min(), and parallel_partition().

Referenced by parallel_sort_qs_conquer().

template<typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::parallel_sort_qsb ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
thread_index_t  num_threads 
) [inline]

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 418 of file balanced_quicksort.h.

References _GLIBCXX_CALL, and qsb_conquer().

Referenced by parallel_sort().

template<typename InputIterator , class OutputIterator >
OutputIterator __gnu_parallel::parallel_unique_copy ( InputIterator  first,
InputIterator  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 181 of file unique_copy.h.

References parallel_unique_copy().

template<typename InputIterator , class OutputIterator , class BinaryPredicate >
OutputIterator __gnu_parallel::parallel_unique_copy ( InputIterator  first,
InputIterator  last,
OutputIterator  result,
BinaryPredicate  binary_pred 
) [inline]

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 51 of file unique_copy.h.

References _GLIBCXX_CALL, and equally_split().

Referenced by parallel_unique_copy().

template<typename RandomAccessIterator , typename Comparator >
void __gnu_parallel::qsb_conquer ( QSBThreadLocal< RandomAccessIterator > **  tls,
RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
thread_index_t  iam,
thread_index_t  num_threads,
bool  parent_wait 
) [inline]

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 163 of file balanced_quicksort.h.

References __gnu_parallel::QSBThreadLocal< RandomAccessIterator >::elements_leftover, __gnu_parallel::QSBThreadLocal< RandomAccessIterator >::initial, qsb_divide(), and qsb_local_sort_with_helping().

Referenced by parallel_sort_qsb().

template<typename RandomAccessIterator , typename Comparator >
std::iterator_traits<RandomAccessIterator>::difference_type __gnu_parallel::qsb_divide ( RandomAccessIterator  begin,
RandomAccessIterator  end,
Comparator  comp,
thread_index_t  num_threads 
) [inline]

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 RandomAccessIterator , typename Comparator >
void __gnu_parallel::qsb_local_sort_with_helping ( QSBThreadLocal< RandomAccessIterator > **  tls,
Comparator &  comp,
int  iam,
bool  wait 
) [inline]

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 239 of file balanced_quicksort.h.

References _GLIBCXX_ASSERTIONS, __gnu_parallel::QSBThreadLocal< RandomAccessIterator >::elements_leftover, __gnu_parallel::_Settings::get(), __gnu_parallel::QSBThreadLocal< RandomAccessIterator >::initial, __gnu_parallel::QSBThreadLocal< RandomAccessIterator >::leftover_parts, __gnu_parallel::QSBThreadLocal< RandomAccessIterator >::num_threads, __gnu_parallel::RestrictedBoundedConcurrentQueue< T >::pop_front(), __gnu_parallel::RestrictedBoundedConcurrentQueue< T >::push_front(), __gnu_parallel::_Settings::sort_qsb_base_case_maximal_n, and yield().

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 T >
T __gnu_parallel::round_up_to_pow2 ( T  x  )  [inline]

Round up to the next greater power of 2.

Parameters:
x Integer to round up

Definition at line 241 of file random_shuffle.h.

References __log2().

Referenced by parallel_random_shuffle_drs(), and sequential_random_shuffle().

template<typename _RandomAccessIterator1 , typename _RandomAccessIterator2 , typename Pred >
_RandomAccessIterator1 __gnu_parallel::search_template ( _RandomAccessIterator1  begin1,
_RandomAccessIterator1  end1,
_RandomAccessIterator2  begin2,
_RandomAccessIterator2  end2,
Pred  pred 
) [inline]

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 82 of file search.h.

References _GLIBCXX_CALL, calc_borders(), equally_split(), and min().

template<bool stable, bool sentinels, typename RandomAccessIteratorIterator , typename RandomAccessIterator3 , typename _DifferenceTp , typename Comparator >
RandomAccessIterator3 __gnu_parallel::sequential_multiway_merge ( RandomAccessIteratorIterator  seqs_begin,
RandomAccessIteratorIterator  seqs_end,
RandomAccessIterator3  target,
const typename std::iterator_traits< typename std::iterator_traits< RandomAccessIteratorIterator >::value_type::first_type >::value_type &  sentinel,
_DifferenceTp  length,
Comparator  comp 
) [inline]

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 out output sequence.
comp Comparator.
length Maximum length to merge, possibly larger than the number of elements available.
stable Stable merging incurs a performance penalty.
sentinel The sequences have a sentinel element.
Returns:
End iterator of output sequence.

Definition at line 979 of file multiway_merge.h.

References _GLIBCXX_CALL, _GLIBCXX_PARALLEL_LENGTH, is_sorted(), and merge_advance().

Referenced by multiway_merge(), and multiway_merge_sentinels().

template<typename RandomAccessIterator , typename RandomNumberGenerator >
void __gnu_parallel::sequential_random_shuffle ( RandomAccessIterator  begin,
RandomAccessIterator  end,
RandomNumberGenerator &  rng 
) [inline]

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 394 of file random_shuffle.h.

References __log2(), __gnu_parallel::_Settings::L2_cache_size, std::min(), random_number_pow2(), round_up_to_pow2(), and __gnu_parallel::_Settings::TLB_size.

Referenced by parallel_random_shuffle_drs().

template<typename InputIterator >
void __gnu_parallel::shrink ( std::vector< InputIterator > &  os_starts,
size_t &  count_to_two,
size_t &  range_length 
) [inline]

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 InputIterator >
void __gnu_parallel::shrink_and_double ( std::vector< InputIterator > &  os_starts,
size_t &  count_to_two,
size_t &  range_length,
const bool  make_twice 
) [inline]

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 std::vector< _Tp, _Alloc >::resize(), shrink(), and std::vector< _Tp, _Alloc >::size().

Referenced by list_partition().

void __gnu_parallel::yield (  )  [inline]

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

Definition at line 340 of file parallel/compatibility.h.

Referenced by for_each_template_random_access_workstealing(), and qsb_local_sort_with_helping().

Variable Documentation

const int __gnu_parallel::lcas_t_bits [static]

Number of bits of lcas_t.

Definition at line 149 of file types.h.

Referenced by decode2(), and encode2().

const lcas_t __gnu_parallel::lcas_t_mask [static]

lcas_t with the right half of bits set to 1.

Definition at line 152 of file types.h.

Referenced by decode2().

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