Integer::Partition - Generate all integer partitions of an integer
This document describes version 0.05 of Integer::Partition, released 2013-06-23.
use Integer::Partition; my $i = Integer::Partition->new(4); while (my $p = $i->next) { print join( ' ', @$p ), $/; } # produces 4 3 1 2 2 2 1 1 1 1 1 1 my $j = Integer::Partition->new(5, {lexicographic => 1}); while (my $p = $j->next) { print join( ' ', @$p ), $/; } # produces 1 1 1 1 1 2 1 1 1 2 2 1 3 1 1 3 2 4 1 5
Integer::Partition
takes an integer number and produces an object that can be used to generate all possible integer partitions of the original number in either forward or reverse lexicographic order.
Creates a new Integer::Partition
object. Takes an integer as a parameter. By default, the partitions appear in reverse order, as the algorithm is slightly faster. Forward ordering uses a different, slightly slower algorithm (which is nonetheless much faster than any existing algorithm).
Returns the partition, or undef
when all partitions have been generated.
Resets the object, which causes it to enumerate the arrangements from the beginning.
$p->reset; # begin again
The new()
method was called without an input parameter, which should be a positive integer.
n
is not a positive integerThe new()
method was called with zero or a negative integer.
n
is not an integerThe new()
method was called with a number containing a decimal component. Use int
or sprintf '%d'
on the input if necessary.
This module implements the Zoghbi and Stojmenovic ZS1 and ZS2 algorithms for generating integer partitions. See http://www.site.uottawa.ca/~ivan/F49-int-part.pdf for more information. These algorithms have been proven to have constant average delay, that is, the amount of effort it takes to produce the next result in the series.
They are the fastest known algorithms known for generating integer partitions (with the ZS1 reverse lexicographic order algorithm being slightly faster than the ZS2 lexicographic order algorithm).
The Wikipedia entry on integer partitions
The original 1998 paper written by Zoghbi and Stojmenovic.
None known.
Please report all bugs at http://rt.cpan.org/NoAuth/Bugs.html?Dist=Integer-Partition|rt.cpan.org
Make sure you include the output from the following two commands:
perl -MInteger::Partition -le 'print $Integer::Partition::VERSION' perl -V
Pull requests on Github may be issued at https://github.com/dland/Integer-Partition.
Thanks to Antoine Zoghbi and Ivan Stojmenovic, for sharing their discovery with the world on the internet, and not hiding it in behind some sort of pay-wall.
David Landgren, copyright (C) 2007-2013. All rights reserved.
If you (find a) use this module, I'd love to hear about it. If you want to be informed of updates, send me a note. You know my first name, you know my domain. Can you guess my e-mail address?
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.