README.md

Geometric Random Numbers

Geometric distributed pseudorandom numbers.

Usage

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

geometric( p )

Returns a pseudorandom number drawn from a geometric distribution with success probability p.

var r = geometric( 0.8 );
// returns <number>

If p < 0 or p > 1, the function returns NaN.

var r = geometric( 3.14 );
// returns NaN

r = geometric( -0.5 );
// returns NaN

If p is NaN, the function returns NaN.

var r = geometric( NaN );
// returns NaN

geometric.factory( [p, ][options] )

Returns a pseudorandom number generator (PRNG) for generating pseudorandom numbers drawn from a geometric distribution.

var rand = geometric.factory();

var r = rand( 0.3 );
// returns <number>

If provided p, the returned generator returns random variates from the specified distribution.

var rand = geometric.factory( 0.6 );

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

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

If not provided p, the returned generator requires that p be provided at each invocation.

var rand = geometric.factory();

var r = rand( 0.67 );
// returns <number>

r = rand( 0.42 );
// returns <number>

The function accepts the following options:

• seed: pseudorandom number generator seed.

To seed a pseudorandom number generator, set the seed option.

var rand = geometric.factory({
    'seed': 12345
});

var r = geometric( 0.9 );
// returns <number>

rand = geometric.factory( 0.2, {
    'seed': 12345
});

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

geometric.NAME

The generator name.

var name = geometric.NAME;
// returns 'geometric'

geometric.PRNG

The underlying pseudorandom number generator.

var prng = geometric.PRNG;
// returns <Function>

geometric.SEED

The value used to seed geometric().

var rand;
var r;
var i;

// Generate pseudorandom values...
for ( i = 0; i < 100; i++ ) {
    r = geometric( 20, 0.5 );
}

// Generate the same pseudorandom values...
rand = geometric.factory( 20, 0.5, {
    'seed': geometric.SEED
});
for ( i = 0; i < 100; i++ ) {
    r = rand();
}

Examples

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

var seed;
var rand;
var i;

// Generate pseudorandom numbers...
console.log( '\nseed: %d', geometric.SEED );
for ( i = 0; i < 100; i++ ) {
    console.log( geometric( 0.4 ) );
}

// Create a new pseudorandom number generator...
seed = 1234;
rand = geometric.factory( 0.4, {
    'seed': seed
});
console.log( '\nseed: %d', seed );
for ( i = 0; i < 100; i++ ) {
    console.log( rand() );
}

// Create another pseudorandom number generator using a previous seed...
rand = geometric.factory( 0.4, {
    'seed': geometric.SEED
});
console.log( '\nseed: %d', geometric.SEED );
for ( i = 0; i < 100; i++ ) {
    console.log( rand() );
}