MRG32k3a Combined recursive generator (pseudo-code)

   /* Constants */
   /* First generator */
   a1 = [0, 1403580, -810728]
   m1 = 2**32 - 209
   /* Second Generator */
   a2 = [527612, 0, -1370589]
   m2 = 2**32 - 22853
    
   d = m1 + 1
   
   class MRG32k3a
       x1 = [0, 0, 0]  /* list of three last values of gen #1 */
       x2 = [0, 0, 0]  /* list of three last values of gen #2 */
       
       method seed(u64 seed_state)
           assert seed_state in range >0 and < d 
           x1 = [seed_state, 0, 0]
           x2 = [seed_state, 0, 0]
       end method
           
       method next_int()
           x1i = (a1[0]*x1[0] + a1[1]*x1[1] + a1[2]*x1[2]) mod m1
           x2i = (a2[0]*x2[0] + a2[1]*x2[1] + a2[2]*x2[2]) mod m2
           x1 = [x1i, x1[0], x1[1]]    /* Keep last three */
           x2 = [x2i, x2[0], x2[1]]    /* Keep last three */
           z = (x1i - x2i) % m1
           answer = (z + 1)
           
           return answer
       end method
       
       method next_float():
           return float next_int() / d
       end method
       
   end class


MRG32k3a Use:
   random_gen = instance MRG32k3a
   random_gen.seed(1234567)
   print(random_gen.next_int())   /* 1459213977 */
   print(random_gen.next_int())   /* 2827710106 */
   print(random_gen.next_int())   /* 4245671317 */
   print(random_gen.next_int())   /* 3877608661 */
   print(random_gen.next_int())   /* 2595287583 */
   
       

Task
 Generate a class/set of functions that generates pseudo-random
numbers as shown above.

 Show that the first five integers generated with the seed `1234567`
are as shown above

 Show that for an initial seed of '987654321' the counts of 100_000
repetitions of

   floor(random_gen.next_float() * 5)

Is as follows:

   0: 20002, 1: 20060, 2: 19948, 3: 20059, 4: 19931

 Show your output here, on this page.


use strict;
use warnings;
use feature 'say';
 
package MRG32k3a {
 
    use constant {
        m1 => 2**32 - 209,
        m2 => 2**32 - 22853
    };
 
    use Const::Fast;
    const my @a1 => <     0 1403580  -810728>;
    const my @a2 => <527612       0 -1370589>;
 
    sub new {
        my ($class,undef,$seed) = @_;
        my @x1 = my @x2 = ($seed, 0, 0);
        bless {x1 => \@x1, x2 => \@x2}, $class;
    }
 
    sub next_int {
        my ($self) = @_;
        unshift @{$$self{x1}}, ($a1[0] * $$self{x1}[0] + $a1[1] * $$self{x1}[1] + $a1[2] * $$self{x1}[2]) % m1; pop @{$$self{x1}};
        unshift @{$$self{x2}}, ($a2[0] * $$self{x2}[0] + $a2[1] * $$self{x2}[1] + $a2[2] * $$self{x2}[2]) % m2; pop @{$$self{x2}};
        ($$self{x1}[0] - $$self{x2}[0]) % (m1 + 1)
    }
 
    sub next_float { $_[0]->next_int / (m1 + 1) }
}
 
say 'Seed: 1234567, first 5 values:';
my $rng = MRG32k3a->new( seed => 1234567 );
say $rng->next_int for 1..5;
 
my %h;
say "\nSeed: 987654321, values histogram:";
$rng = MRG32k3a->new( seed => 987654321 );
$h{int 5 * $rng->next_float}++ for 1..100_000;
say "$_ $h{$_}" for sort keys %h;