Entropy
The entropy (in nats) for a Poisson random variable is
where λ is the mean parameter.
Usage
var entropy = require( '@stdlib/stats/base/dists/poisson/entropy' );
entropy( lambda )
Returns the entropy of a Poisson distribution with mean parameter lambda (in nats).
var v = entropy( 9.0 );
// returns ~2.508
v = entropy( 0.5 );
// returns ~0.928
If provided lambda < 0, the function returns NaN.
var v = entropy( -1.0 );
// returns NaN
Examples
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var entropy = require( '@stdlib/stats/base/dists/poisson/entropy' );
var lambda;
var v;
var i;
for ( i = 0; i < 10; i++ ) {
lambda = randu() * 20.0;
v = entropy( lambda );
console.log( 'λ: %d, H(X;λ): %d', lambda.toFixed( 4 ), v.toFixed( 4 ) );
}