NAME Math::Random::MT - The Mersenne Twister PRNG SYNOPSIS ## Object-oriented interface: use Math::Random::MT; $gen = Math::Random::MT->new() # or... $gen = Math::Random::MT->new($seed); # or... $gen = Math::Random::MT->new(@seeds); $seed = $gen->get_seed(); # seed used to generate the random numbers $rand = $gen->rand(42); # random number in the interval [0, 42) $dice = int($gen->rand(6)+1); # random integer between 1 and 6 $coin = $gen->rand() < 0.5 ? # flip a coin "heads" : "tails" $int = $gen->irand(); # random integer in [0, 2^32-1] ## Function-oriented interface: use Math::Random::MT qw(srand rand irand); # now use srand() and rand() as you usually do in Perl DESCRIPTION The Mersenne Twister is a pseudorandom number generator developed by Makoto Matsumoto and Takuji Nishimura. It is described in their paper at <URL:http://www.math.keio.ac.jp/~nisimura/random/doc/mt.ps>. This algorithm has a very uniform distribution and is good for modelling purposes but do not use it for cryptography. This module implements two interfaces: Object-oriented interface new() Creates a new generator that is automatically seeded based on gettimeofday. new($seed) Creates a new generator seeded with an unsigned 32-bit integer. new(@seeds) Creates a new generator seeded with an array of (up to 624) unsigned 32-bit integers. set_seed() Seeds the generator. It takes the same arguments as *new()*. get_seed() Retrieves the value of the seed used. rand($num) Behaves exactly like Perl's builtin rand(), returning a number uniformly distributed in [0, $num) ($num defaults to 1). irand() Returns a 32-bit integer, i.e. an integer uniformly distributed in [0, 2^32-1]. Function-oriented interface srand($seed) Behaves just like Perl's builtin srand(). As in Perl >= 5.14, the seed is returned. If you use this interface, it is strongly recommended that you call *srand()* explicitly, rather than relying on *rand()* to call it the first time it is used. rand($num) Behaves exactly like Perl's builtin rand(), returning a number uniformly distributed in [0, $num) ($num defaults to 1). irand() Returns a 32-bit integer, i.e. an integer uniformly distributed in [0, 2^32-1]. SEE ALSO <URL:http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html> Data::Entropy ACKNOWLEDGEMENTS Sean M. Burke For giving me the idea to write this module. Philip Newton For several useful patches. Florent Angly For implementing seed generation and retrieval. AUTHOR Abhijit Menon-Sen <email@example.com> Copyright 2001 Abhijit Menon-Sen. All rights reserved. Based on the C implementation of MT19937 Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura This software is distributed under a (three-clause) BSD-style license. See the LICENSE file in the distribution for details.