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.IX Title "Math::GSL::Sort 3pm"
.TH Math::GSL::Sort 3pm 2024-03-07 "perl v5.38.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification. Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
Math::GSL::Sort \- Functions for sorting data
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 5
\& use Math::GSL::Sort qw/:all/;
\& my $x = [ 2**15, 1.67, 20e5, \-17, 6900, 1/3 , 42e\-10 ];
\& my $sorted = gsl_sort($x, 1, $#$x+1 );
\& my $numbers = [ map { rand(100) } (1..100) ];
\& my ($status, $smallest10) = gsl_sort_smallest($array, 10, $x, 1, $#$x+1);
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
.IP \(bu 4
gsl_sort_vector($v)
.Sp
This function sorts the elements of the vector \f(CW$v\fR into ascending numerical
order.
.IP \(bu 4
gsl_sort_vector_index($p, \f(CW$v\fR)
.Sp
This function indirectly sorts the elements of the vector \f(CW$v\fR into ascending
order, storing the resulting permutation in \f(CW$p\fR. The elements of \f(CW$p\fR give the
index of the vector element which would have been stored in that position if
the vector had been sorted in place. The first element of \f(CW$p\fR gives the index
of the least element in \f(CW$v\fR, and the last element of \f(CW$p\fR gives the index of the
greatest element in \f(CW$v\fR. The vector \f(CW$v\fR is not changed.
.IP \(bu 4
gsl_sort_vector_smallest($array, \f(CW$k\fR, \f(CW$vector\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
\&\f(CW$k\fR smallest elements of the vector \f(CW$v\fR. \f(CW$k\fR must be less than or equal to the
length of the vector \f(CW$v\fR.
.IP \(bu 4
gsl_sort_vector_smallest_index($p, \f(CW$k\fR, \f(CW$v\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
indices of the \f(CW$k\fR smallest elements of the vector \f(CW$v\fR. \f(CW$p\fR must be a prealocated
array reference. This should be removed in further versions. \f(CW$k\fR must be less
than or equal to the length of the vector \f(CW$v\fR.
.IP \(bu 4
gsl_sort_vector_largest($array, \f(CW$k\fR, \f(CW$vector\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
\&\f(CW$k\fR largest elements of the vector \f(CW$v\fR. \f(CW$k\fR must be less than or equal to the
length of the vector \f(CW$v\fR.
.IP \(bu 4
gsl_sort_vector_largest_index($p, \f(CW$k\fR, \f(CW$v\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
indices of the \f(CW$k\fR largest elements of the vector \f(CW$v\fR. \f(CW$p\fR must be a prealocated
array reference. This should be removed in further versions. \f(CW$k\fR must be less
than or equal to the length of the vector \f(CW$v\fR.
.IP \(bu 4
gsl_sort($data, \f(CW$stride\fR, \f(CW$n\fR)
.Sp
This function returns an array reference to the sorted \f(CW$n\fR elements of the
array \f(CW$data\fR with stride \f(CW$stride\fR into ascending numerical order.
.IP \(bu 4
gsl_sort_index($p, \f(CW$data\fR, \f(CW$stride\fR, \f(CW$n\fR)
.Sp
This function indirectly sorts the \f(CW$n\fR elements of the array \f(CW$data\fR with stride
\&\f(CW$stride\fR into ascending order, outputting the permutation in the foram of an
array. \f(CW$p\fR must be a prealocated array reference. This should be removed in
further versions. The array \f(CW$data\fR is not changed.
.IP \(bu 4
gsl_sort_smallest($array, \f(CW$k\fR, \f(CW$data\fR, \f(CW$stride\fR, \f(CW$n\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
\&\f(CW$k\fR smallest elements of the array \f(CW$data\fR, of size \f(CW$n\fR and stride \f(CW$stride\fR, in
ascending numerical. The size \f(CW$k\fR of the subset must be less than or equal to
\&\f(CW$n\fR. The data \f(CW$src\fR is not modified by this operation. \f(CW$array\fR must be a
prealocated array reference. This should be removed in further versions.
.IP \(bu 4
gsl_sort_smallest_index($p, \f(CW$k\fR, \f(CW$src\fR, \f(CW$stride\fR, \f(CW$n\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
indices of the \f(CW$k\fR smallest elements of the array \f(CW$src\fR, of size \f(CW$n\fR and stride
\&\f(CW$stride\fR. The indices are chosen so that the corresponding data is in ascending
numerical order. \f(CW$k\fR must be less than or equal to \f(CW$n\fR. The data \f(CW$src\fR is not
modified by this operation. \f(CW$p\fR must be a prealocated array reference. This
should be removed in further versions.
.IP \(bu 4
gsl_sort_largest($array, \f(CW$k\fR, \f(CW$data\fR, \f(CW$stride\fR, \f(CW$n\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
\&\f(CW$k\fR largest elements of the array \f(CW$data\fR, of size \f(CW$n\fR and stride \f(CW$stride\fR, in
ascending numerical. The size \f(CW$k\fR of the subset must be less than or equal to
\&\f(CW$n\fR. The data \f(CW$src\fR is not modified by this operation. \f(CW$array\fR must be a
prealocated array reference. This should be removed in further versions.
.IP \(bu 4
gsl_sort_largest_index($p, \f(CW$k\fR, \f(CW$src\fR, \f(CW$stride\fR, \f(CW$n\fR)
.Sp
This function outputs 0 if the operation succeeded, 1 otherwise and then the
indices of the \f(CW$k\fR largest elements of the array \f(CW$src\fR, of size \f(CW$n\fR and stride
\&\f(CW$stride\fR. The indices are chosen so that the corresponding data is in ascending
numerical order. \f(CW$k\fR must be less than or equal to \f(CW$n\fR. The data \f(CW$src\fR is not
modified by this operation. \f(CW$p\fR must be a prealocated array reference. This
should be removed in further versions.
.PP
.Vb 1
\& Here is a complete list of all tags for this module :
.Ve
.IP all 4
.IX Item "all"
.PD 0
.IP plain 4
.IX Item "plain"
.IP vector 4
.IX Item "vector"
.PD
.PP
For more information on the functions, we refer you to the GSL official
documentation:
.SH PERFORMANCE
.IX Header "PERFORMANCE"
In the source code of Math::GSL, the file "examples/benchmark/sort" compares
the performance of \fBgsl_sort()\fR to Perl's builtin \fBsort()\fR function. Its first
argument is the number of iterations and the second is the size of the array
of numbers to sort. For example, to see a benchmark of 1000 iterations for
arrays of size 50000 you would type
.PP
.Vb 1
\& ./examples/benchmark/sort 1000 50000
.Ve
.PP
Initial benchmarks indicate just slightly above a 2x performance increase
over \fBsort()\fR for arrays of between 5000 and 50000 elements. This may mostly
be due to the fact that \fBgsl_sort()\fR takes and returns a reference while \fBsort()\fR
takes and returns a plain list.
.SH AUTHORS
.IX Header "AUTHORS"
Jonathan "Duke" Leto and Thierry Moisan
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
Copyright (C) 2008\-2023 Jonathan "Duke" Leto and Thierry Moisan
.PP
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.