Pseudo-random numbers/Combined recursive generator MRG32k3a: Difference between revisions

=={{header|Perl}}==

<lang perl>use strict;

use warnings;

use feature 'say';

{ package MRG32k3a;

our(@x1,@x2);

our $m1 = 2**32 - 209;

our $m2 = 2**32 - 22853;

our @a1 = < 0 1403580 -810728>;

our @a2 = <527612 0 -1370589>;

sub new { @x1 = @x2 = ($_[2], 0, 0) }

sub next_int {

unshift @x1, ($a1[0] * $x1[0] + $a1[1] * $x1[1] + $a1[2] * $x1[2]) % $m1; pop @x1;

unshift @x2, ($a2[0] * $x2[0] + $a2[1] * $x2[1] + $a2[2] * $x2[2]) % $m2; pop @x2;

($x1[0] - $x2[0]) % ($m1 + 1)

}

sub next_float { next_int() / ($m1 + 1) }

}

say 'Seed: 1234567, first 5 values:';

my $rng = MRG32k3a->new( seed => 1234567 );

say MRG32k3a->next_int($rng) for 1..5;

my %h;

say "\nSeed: 987654321, values histogram:";

$rng = MRG32k3a->new( seed => 987654321 );

$h{int 5 * MRG32k3a->next_float($rng)}++ for 1..100_000;

say "$_ $h{$_}" for sort keys %h;</lang>

{{out}}

<pre>Seed: 1234567, first 5 values:

1459213977

2827710106

4245671317

3877608661

2595287583

Seed: 987654321, values histogram:

0 20002

1 20060

2 19948

3 20059

4 19931</pre>