NAME
Math::Random::Biski64 - Fast 64-bit PRNG with guaranteed minimum 2^64 period
SYNOPSIS
use Math::Random::Biski64;
# Local copy of the random number generator to play with
my $rng = Math::Random::Biski64->new();
my $num = $rng->next_u64();
# Or create one with a specific 64bit seed
my $rng2 = Math::Random::Biski64->new(12345);
my $num = $rng2->next_u64();DESCRIPTION
This module implements the Biski64 algorithm, a fast and robust non-cryptographic 64-bit pseudo-random number generator. It uses a 64-bit Weyl sequence to guarantee a minimum period of 2^64, and is designed for applications where speed and statistical quality are important.
On module load, a default generator is automatically seeded from the OS random source (/dev/urandom on Unix, RtlGenRandom on Windows).
METHODS
new($seed?)
Create a new generator. If $seed is provided, the generator is seeded via seed. Otherwise, the generator is seeded from the OS random source.
seed($seed)
Initialize the generator from a 64-bit seed using SplitMix64 to expand the seed into the full internal state, followed by a 16-iteration warm-up.
next_u64()
Returns the next 64-bit random integer.
next_u32()
Returns the next 32-bit random integer (upper 32 bits of the next_u64 output).
next_double()
Returns a random double in [0, 1).
rand_integer($min, $max)
Returns an unbiased random integer in the inclusive range $min to $max. Uses rejection sampling to eliminate modulo bias: if the raw 64-bit value exceeds the largest multiple of the range that fits in 2^64, it is rejected and a new value is drawn.
Returns $min unchanged if $min >= $max.
shuffle_array(@array)
Returns a new array containing the same elements as @array but randomly shuffled using the Fisher-Yates algorithm. The original array is not modified.
my @cards = 1..52;
my @shuffled = $rng->shuffle_array(@cards);random_elem(@array)
Returns a randomly selected element from @array, chosen with an unbiased uniform distribution. Returns undef if @array is empty.
my @colors = qw(red green blue);
my $color = $rng->random_elem(@colors);ALGORITHM
The Biski64 state consists of three 64-bit integers: fast_loop, mix, and loop_mix. On each call:
output = mix + loop_mix
loop_mix = fast_loop ^ mix
mix = rotl(mix, 16) + rotl(loop_mix, 40)
fast_loop += 0x9999999999999999SEE ALSO
https://github.com/danielcota/biski64
LICENSE
MIT