NAME
Integer::Partition  Generate all integer partitions of an integer
VERSION
This document describes version 0.05 of Integer::Partition, released 20130623.
SYNOPSIS
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
DESCRIPTION
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.
METHODS
 new

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).  next

Returns the partition, or
undef
when all partitions have been generated.  reset

Resets the object, which causes it to enumerate the arrangements from the beginning.
$p>reset; # begin again
DIAGNOSTICS
missing or undefined input
The new()
method was called without an input parameter, which should be a positive integer.
n
is not a positive integer
The new()
method was called with zero or a negative integer.
n
is not an integer
The new()
method was called with a number containing a decimal component. Use int
or sprintf '%d'
on the input if necessary.
NOTES
This module implements the Zoghbi and Stojmenovic ZS1 and ZS2 algorithms for generating integer partitions. See http://www.site.uottawa.ca/~ivan/F49intpart.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).
SEE ALSO
http://en.wikipedia.org/wiki/Integer_partition
The Wikipedia entry on integer partitions
http://www.site.uottawa.ca/~ivan/F49intpart.pdf
The original 1998 paper written by Zoghbi and Stojmenovic.
BUGS
None known.
Please report all bugs at http://rt.cpan.org/NoAuth/Bugs.html?Dist=IntegerPartitionrt.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/IntegerPartition.
ACKNOWLEDGEMENTS
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 paywall.
AUTHOR
David Landgren, copyright (C) 20072013. All rights reserved.
http://www.landgren.net/perl/
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 email address?
LICENSE
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.