Mersenne Twister

Usage

var mt19937 = require( '@stdlib/random/base/mt19937' );

mt19937()

Returns a pseudorandom integer on the interval [0, 4294967295].

var r = mt19937();
// returns <number>

mt19937.normalized()

Returns a pseudorandom number on the interval [0, 1) with 53-bit precision.

var r = mt19937.normalized();
// returns <number>

mt19937.factory( [options] )

Returns a 32-bit Mersenne Twister pseudorandom number generator.

var rand = mt19937.factory();

The function accepts the following options:

• seed: pseudorandom number generator seed.
• state: a Uint32Array containing pseudorandom number generator state. If provided, the function ignores the seed option.
• copy: boolean indicating whether to copy a provided pseudorandom number generator state. Setting this option to false allows sharing state between two or more pseudorandom number generators. Setting this option to true ensures that a returned generator has exclusive control over its internal state. Default: true.

By default, a random integer is used to seed the returned generator. To seed the generator, provide either a nonzero integer on the interval [1, 4294967295]

var rand = mt19937.factory({
    'seed': 1234
});

var r = rand();
// returns 822569775

or, for arbitrary length seeds, an array-like object containing unsigned 32-bit integers

var Uint32Array = require( '@stdlib/array/uint32' );

var rand = mt19937.factory({
    'seed': new Uint32Array( [ 291, 564, 837, 1110 ] )
});

var r = rand();
// returns 1067595299

To return a generator having a specific initial state, set the generator state option.

var rand;
var bool;
var r;
var i;

// Generate pseudorandom numbers, thus progressing the generator state:
for ( i = 0; i < 1000; i++ ) {
    r = mt19937();
}

// Create a new MT19937 PRNG initialized to the current state of `mt19937`:
rand = mt19937.factory({
    'state': mt19937.state
});

// Test that the generated pseudorandom numbers are the same:
bool = ( rand() === mt19937() );
// returns true

mt19937.NAME

The generator name.

var str = mt19937.NAME;
// returns 'mt19937'

mt19937.MIN

Minimum possible value.

var min = mt19937.MIN;
// returns 0

mt19937.MAX

Maximum possible value.

var max = mt19937.MAX;
// returns 4294967295

mt19937.seed

The value used to seed mt19937().

var rand;
var r;
var i;

// Generate pseudorandom values...
for ( i = 0; i < 100; i++ ) {
    r = mt19937();
}

// Generate the same pseudorandom values...
rand = mt19937.factory({
    'seed': mt19937.seed
});
for ( i = 0; i < 100; i++ ) {
    r = rand();
}

mt19937.seedLength

Length of generator seed.

var len = mt19937.seedLength;
// returns <number>

mt19937.state

Writable property for getting and setting the generator state.

var r = mt19937();
// returns <number>

r = mt19937();
// returns <number>

// ...

// Get a copy of the current state:
var state = mt19937.state;
// returns <Uint32Array>

r = mt19937();
// returns <number>

r = mt19937();
// returns <number>

// Reset the state:
mt19937.state = state;

// Replay the last two pseudorandom numbers:
r = mt19937();
// returns <number>

r = mt19937();
// returns <number>

// ...

mt19937.stateLength

Length of generator state.

var len = mt19937.stateLength;
// returns <number>

mt19937.byteLength

Size (in bytes) of generator state.

var sz = mt19937.byteLength;
// returns <number>

mt19937.toJSON()

Serializes the pseudorandom number generator as a JSON object.

var o = mt19937.toJSON();
// returns { 'type': 'PRNG', 'name': '...', 'state': {...}, 'params': [] }