Package Exports

@stdlib/stats-base-dists-beta-mode

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Readme

Mode

Beta distribution mode.

The mode for a beta random variable is

for α > 1 and β > 1. For other values of first shape parameter α and second shape parameter β, the mode is not defined.

Installation

npm install @stdlib/stats-base-dists-beta-mode

Usage

var mode = require( '@stdlib/stats-base-dists-beta-mode' );

mode( alpha, beta )

Returns the mode of a beta distribution with parameters alpha (first shape parameter) and beta (second shape parameter).

var v = mode( 2.5, 1.5 );
// returns 0.75

v = mode( 4.0, 12.0 );
// returns ~0.214

v = mode( 8.0, 2.0 );
// returns 0.875

If provided NaN as any argument, the function returns NaN.

var v = mode( NaN, 2.0 );
// returns NaN

v = mode( 2.0, NaN );
// returns NaN

If provided alpha <= 1, the function returns NaN.

var v = mode( 0.5, 1.0 );
// returns NaN

v = mode( -1.0, 1.0 );
// returns NaN

If provided beta <= 1, the function returns NaN.

var v = mode( 1.0, 0.5 );
// returns NaN

v = mode( 1.0, -1.0 );
// returns NaN

Examples

var randu = require( '@stdlib/random-base-randu' );
var EPS = require( '@stdlib/constants-float64-eps' );
var mode = require( '@stdlib/stats-base-dists-beta-mode' );

var alpha;
var beta;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    alpha = ( randu()*10.0 ) + 1.0 + EPS;
    beta = ( randu()*10.0 ) + 1.0 + EPS;
    v = mode( alpha, beta );
    console.log( 'α: %d, β: %d, mode(X;α,β): %d', alpha.toFixed( 4 ), beta.toFixed( 4 ), v.toFixed( 4 ) );
}

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

License

See LICENSE.

@stdlib/stats-base-dists-beta-mode