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( #3333=superdoc: print w/replies, xml ) Need Help??
For cases when you can't, or don't want to, rely on an external module, this is quick, simple, and good enough for non scientific computing:
sub make_random_generator {
    my ($seed, $min, $max) = @_;
    # DO NOT CHANGE THESE
    my $a = 7 ** 5;
    my $m = (2 ** 31) - 1;
    # if seed was zero this generator will return zeros 
    # forever, set it to some arbitrary value
    if ($seed == 0) { $seed = 12345678; }
    unless (defined $min) { $min = 0; }
    unless (defined $max) { $max = $m; }
    if ($max < $min) {
        my $t = $min;
        $min = $max;
        $max = $t;
    }
    return sub {
        $seed = ($a * $seed) % $m;
        # "scale" $seed to the range ($min,$max)
        return int ((($seed / $m) * ($max - $min)) + $min);
    }
}
use it like this:
for my $seq_n (1..10) {
    print "random sequence with seed $seq_n:\n";
    my $gen = make_random_generator(rand, 0, 1000);
    print join ", ", map { $gen->() } 1 .. 10;
    print "\n";
}
this will return the same 10 pseudo random sequences every time you run it.

In reply to Re: Generating Repeatable Pseudorandom Sequences by Anonymous Monk
in thread Generating Repeatable Pseudorandom Sequences by mp

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