@stdlib/stats-base-dists-discrete-uniform-entropy

Entropy

Discrete uniform distribution entropy.

The entropy (in nats) for a discrete uniform random variable is

where a is the minimum support and b is the maximum support. The parameters must satisfy a < b.

Installation

npm install @stdlib/stats-base-dists-discrete-uniform-entropy

Usage

var entropy = require( '@stdlib/stats-base-dists-discrete-uniform-entropy' );

entropy( a, b )

Returns the entropy of a discrete uniform distribution with minimum support a and maximum support b (in nats).

var v = entropy( 0, 1 );
// returns ~0.693

v = entropy( 4, 12 );
// returns ~2.197

v = entropy( 2, 8 );
// returns ~1.946

If a or b is not an integer value, the function returns NaN.

var v = entropy( 0.1, 2 );
// returns NaN

v = entropy( 0, 2.2 );
// returns NaN

v = entropy( NaN, 2 );
// returns NaN

v = entropy( 2, NaN );
// returns NaN

If provided a > b, the function returns NaN.

var v = entropy( 3, 2 );
// returns NaN

v = entropy( -1, -2 );
// returns NaN

Examples

var randint = require( '@stdlib/random-base-discrete-uniform' );
var entropy = require( '@stdlib/stats-base-dists-discrete-uniform-entropy' );

var randa = randint.factory( 0, 10 );
var randb = randint.factory();
var a;
var b;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    a = randa();
    b = randb( a, a+randa() );
    v = entropy( a, b );
    console.log( 'a: %d, b: %d, H(X;a,b): %d', a.toFixed( 4 ), b.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.