Entropy

Pareto (Type I) distribution differential entropy.

The differential entropy (in nats) for a Pareto (Type I) random variable is

where α > 0 is the shape parameter and β > 0 is the scale parameter.

Installation

npm install @stdlib/stats-base-dists-pareto-type1-entropy

Usage

var entropy = require( '@stdlib/stats-base-dists-pareto-type1-entropy' );

entropy( alpha, beta )

Returns the differential entropy of a Pareto (Type I) distribution with parameters shape parameter alpha and scale parameter beta (in nats).

var v = entropy( 2.0, 1.0 );
// returns ~0.807

v = entropy( 4.0, 12.0 );
// returns ~2.349

v = entropy( 8.0, 2.0 );
// returns ~-0.261

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

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

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

If provided alpha <= 0, the function returns NaN.

var v = entropy( 0.0, 1.0 );
// returns NaN

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

If provided beta <= 0, the function returns NaN.

var v = entropy( 1.0, 0.0 );
// returns NaN

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

Examples

var randu = require( '@stdlib/random-base-randu' );
var EPS = require( '@stdlib/constants-float64-eps' );
var entropy = require( '@stdlib/stats-base-dists-pareto-type1-entropy' );

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

for ( i = 0; i < 10; i++ ) {
    alpha = ( randu()*10.0 ) + EPS;
    beta = ( randu()*10.0 ) + EPS;
    v = entropy( alpha, beta );
    console.log( 'α: %d, β: %d, h(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.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.