Twister

Wrapper for the Mersenne twister.

The Mersenne twister is a pseudorandom number generator linked to CR developed in 1997 by Makoto Matsumoto and Takuji Nishimura that is based on a matrix linear recurrence over a finite binary field F2. It provides for fast generation of very high quality pseudorandom numbers, having been designed specifically to rectify many of the flaws found in older algorithms.

Mersenne Twister has the following desirable properties:

1. It was designed to have a period of 2^19937 - 1 (the creators
   of the algorithm proved this property).

2. It has a very high order of dimensional equidistribution.
   This implies that there is negligible serial correlation between
   successive values in the output sequence.

3. It passes numerous tests for statistical randomness, including
   the stringent Diehard tests.

4. It is fast.

struct Twister {

alias toInt = natural;

alias toReal = fraction;

static __gshared

Twister instance;

static Twister opCall();

uint natural(uint max);

uint natural(uint min, uint max);

uint natural(bool pAddEntropy);

double inclusive();

double exclusive();

double fraction();

double fractionEx();

void seed();

void seed(uint s, bool pAddEntropy);

void init(const(uint[]) init_key, bool pAddEntropy);

}

Members

Aliases

toInt alias toInt = natural: Undocumented in source.
toReal alias toReal = fraction: Undocumented in source.

Functions

exclusive double exclusive(): generates a random number on (0,1) interval
fraction double fraction(): generates a random number on [0,1) interval
fractionEx double fractionEx(): generates a random number on [0,1) with 53-bit resolution
inclusive double inclusive(): generates a random number on [0,1] interval
init void init(const(uint[]) init_key, bool pAddEntropy): initialize by an array with array-length init_key is the array for initializing keys
natural uint natural(uint max): Returns X such that 0 <= X < max
natural uint natural(uint min, uint max): Returns X such that min <= X < max
natural uint natural(bool pAddEntropy): Returns X such that 0 <= X <= uint.max
seed void seed(): Seed the generator with current time
seed void seed(uint s, bool pAddEntropy): initializes the generator with a seed

Static functions

opCall Twister opCall(): Creates and seeds a new generator with the current time

Static variables

instance Twister instance;: A global, shared instance, seeded via startup time