README.md

Mean

Laplace distribution expected value.

The expected value for a Laplace random variable with location μ and scale b > 0 is

$$\mathbb{E}\left[ X \right] = \mu$$

Usage

var mean = require( '@stdlib/stats/base/dists/laplace/mean' );

mean( mu, b )

Returns the expected value for a Laplace distribution with location parameter mu and scale parameter b.

var y = mean( 2.0, 1.0 );
// returns 2.0

y = mean( 0.0, 1.0 );
// returns 0.0

y = mean( -1.0, 4.0 );
// returns -1.0

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

var y = mean( NaN, 1.0 );
// returns NaN

y = mean( 0.0, NaN );
// returns NaN

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

var y = mean( 0.0, 0.0 );
// returns NaN

y = mean( 0.0, -1.0 );
// returns NaN

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var mean = require( '@stdlib/stats/base/dists/laplace/mean' );

var opts = {
    'dtype': 'float64'
};
var mu = uniform( 10, -5.0, 5.0, opts );
var b = uniform( 10, 0.0, 20.0, opts );

logEachMap( 'µ: %0.4f, b: %0.4f, E(X;µ,b): %0.4f', mu, b, mean );

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C APIs

Usage

#include "stdlib/stats/base/dists/laplace/mean.h"

stdlib_base_dists_laplace_mean( mu, b )

Returns the expected value for a Laplace distribution with location mu and scale b.

double out = stdlib_base_dists_laplace_mean( 2.0, 1.0 );
// returns 2.0

The function accepts the following arguments:

• mu: [in] double location parameter.
• b: [in] double scale parameter.

double stdlib_base_dists_laplace_mean( const double mu, const double b );

Examples

#include "stdlib/stats/base/dists/laplace/mean.h"
#include <stdlib.h>
#include <stdio.h>

static double random_uniform( const double min, const double max ) {
    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
    return min + ( v*(max-min) );
}

int main( void ) {
    double scale;
    double mu;
    double y;
    int i;

    for ( i = 0; i < 25; i++ ) {
        mu = random_uniform( -5.0, 5.0 );
        scale = random_uniform( 0.0, 20.0 );
        y = stdlib_base_dists_laplace_mean( mu, scale );
        printf( "µ: %lf, scale: %lf, E(X;µ,scale): %lf\n", mu, scale, y );
    }
}