This module uses a 64-bit Mersenne Twister to generate pseudo-random numbers.

The output of an MT64 generator is completely deterministic and depends only on the initial seed value — i.e. the sequence of numbers generated will always be identical for a given seed.

Classes

MT64() -> MT64

Returns a new 64-bit Mersenne Twister for generating pseudo-random numbers. The generator is automatically initialized with a random seed.

An MT64 object supports the following methods:

:rand_float() -> f64

Returns a uniformly-distributed random float from the half-open interval [0, 1) — i.e. the interval from zero up to but not including 1. The generator produces floats with 53 bits of precision.

:rand_int(n: i64) -> i64

Returns a uniformly-distributed random integer from the half-open interval [0, n) — i.e. the interval from zero up to but not including n, where n is a positive integer.

:rand_int_in_range(lower: i64, upper: i64) -> i64

Returns a uniformly-distributed random integer from the half-open interval [lower, upper) — i.e. the interval from lower up to but not including upper.

The arguments can be positive or negative or mixed as long as lower is less than or equal to upper.

:seed_with_array(arg: buf|str)

Seeds (or re-seeds) the generator using the content of a string or buffer, treated as an array of bytes. Uses up to the first 2,496 bytes of content.

If arg contains less than 8 bytes of content, this falls back on calling :seed_with_hash().

:seed_with_hash(arg: any)

Seeds (or re-seeds) the generator using the argument's 64-bit hash value.