

 
Manual Reference Pages  MATH::RANDOM::MT (3)
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NAME
Math::Random::MT  The Mersenne Twister PRNG
CONTENTS
SYNOPSIS
## Objectoriented 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, 2^321]
## Functionoriented 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:
new()

Creates a new generator that is automatically seeded based on gettimeofday.

new($seed)

Creates a new generator seeded with an unsigned 32bit integer.

new(@seeds)

Creates a new generator seeded with an array of (up to 624) unsigned
32bit integers.

set_seed()

Seeds the generator and returns the seed used. 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 32bit integer, i.e. an integer uniformly distributed in [0, 2^321].


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 32bit integer, i.e. an integer uniformly distributed in [0, 2^321].


SEE ALSO
<URL:http://www.math.sci.hiroshimau.ac.jp/~mmat/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 MenonSen <ams@toroid.org>
Copyright 2001 Abhijit MenonSen. 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 (threeclause) BSDstyle license.
See the LICENSE file in the distribution for details.
perl v5.20.3  MT (3)  20151127 
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