David Golden > Math-Random-OO-0.21 > Math::Random::OO::Normal

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Module Version: 0.21   Source   Latest Release: Math-Random-OO-0.22

NAME ^

Math::Random::OO::Normal - Generates random numbers from the normal (Gaussian) distribution

SYNOPSIS ^

  use Math::Random::OO::Normal;
  push @prngs,
      Math::Random::OO::Normal->new(),     # mean 0, stdev 1
      Math::Random::OO::Normal->new(5),    # mean 5, stdev 1
      Math::Random::OO::Normal->new(1,3);  # mean 1, stdev 3
  $_->seed(42) for @prngs;
  print( $_->next() . "\n" ) for @prngs;

DESCRIPTION ^

This subclass of Math::Random::OO generates random reals from the normal probability distribution, also called the Gaussian or bell-curve distribution.

The module generates random normals from the inverse of the cumulative normal distribution using an approximation algorithm developed by Peter J. Acklam and released into the public domain. This algorithm claims a relative error of less than 1.15e-9 over the entire region.

See http://home.online.no/~pjacklam/notes/invnorm/ for details and discussion.

USAGE ^

new

 $prng1 = Math::Random::OO::Normal->new();
 $prng2 = Math::Random::OO::Normal->new($mean);
 $prng3 = Math::Random::OO::Normal->new($mean,$stdev);

new takes up to two optional parameters and returns a new Math::Random::OO::Normal object. With no parameters, the object generates random numbers from the standard normal distribution (mean zero, standard deviation one). With a single parameter, the object generates random numbers with mean equal to the parameter and standard deviation of one. With two parameters, the object generates random numbers with mean equal to the first parameter and standard deviation equal to the second parameter. (Standard deviation should be positive, but this module takes the absolute value of the parameter just in case.)

seed

 $rv = $prng->seed( @seeds );

This method seeds the random number generator. At the moment, only the first seed value matters.

next

 $rnd = $prng->next();

This method returns the next random number from the random number generator. It does not take any parameters.

BUGS ^

Please report bugs using the CPAN Request Tracker at

http://rt.cpan.org/NoAuth/Bugs.html?Dist=Math-Random-OO

AUTHOR ^

David A. Golden (DAGOLDEN)

dagolden@dagolden.com

http://dagolden.com/

COPYRIGHT ^

Copyright (c) 2004 by David A. Golden

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO ^

Math::Random::OO

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