Median

Kumaraswamy's double bounded distribution median.

The median for a Kumaraswamy's double bounded random variable is

where a is the first shape parameter and b the second shape parameter.

Usage

var median = require( '@stdlib/stats/base/dists/kumaraswamy/median' );

median( a, b )

Returns the median of a Kumaraswamy's double bounded distribution with first shape parameter a and second shape parameter b.

var v = median( 1.0, 1.0 );
// returns 0.5

v = median( 4.0, 12.0 );
// returns ~0.487

v = median( 2.0, 8.0 );
// returns ~0.288

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

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

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

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

var y = median( -1.0, 0.5 );
// returns NaN

y = median( 0.0, 0.5 );
// returns NaN

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

var y = median( 0.5, -1.0 );
// returns NaN

y = median( 0.5, 0.0 );
// returns NaN

Examples

var randu = require( '@stdlib/random/base/randu' );
var median = require( '@stdlib/stats/base/dists/kumaraswamy/median' );

var a;
var b;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    a = randu() * 10.0;
    b = randu() * 10.0;
    v = median( a, b );
    console.log( 'a: %d, b: %d, Median(X;a,b): %d', a.toFixed( 4 ), b.toFixed( 4 ), v.toFixed( 4 ) );
}

C APIs

Usage

#include "stdlib/stats/base/dists/kumaraswamy/median.h"

stdlib_base_dists_kumaraswamy_median( a, b )

Returns the median of a Kumaraswamy's double bounded distribution with first shape parameter a and second shape parameter b.

double out = stdlib_base_dists_kumaraswamy_median( 2.0, 3.0 );
// returns ~1.817

The function accepts the following arguments:

a: [in] double first shape parameter.
b: [in] double second shape parameter.

double stdlib_base_dists_kumaraswamy_median( const double a, const double b );

Examples

#include "stdlib/stats/base/dists/kumaraswamy/median.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 a;
    double b;
    double y;
    int i;

    for ( i = 0; i < 25; i++ ) {
        a = random_uniform( 0.1, 10.0 );
        b = random_uniform( 0.1, 10.0 );
        y = stdlib_base_dists_kumaraswamy_median( a, b );
        printf( "a: %lf, b: %lf, Median(a, b): %lf\n", a, b, y );
    }

    return 0;
}