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About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

Median

NPM version Build Status Coverage Status

Exponential distribution median.

The median for an exponential random variable is

$$\mathop{\mathrm{Median}}\left( X \right) = \lambda^{−1} \ln(2)$$

where λ is the rate parameter.

Usage

import median from 'https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-dists-exponential-median@esm/index.mjs';

median( lambda )

Returns the median of a exponential distribution with rate parameter lambda.

var v = median( 9.0 );
// returns ~0.077

v = median( 0.5 );
// returns ~1.386

If provided lambda < 0, the function returns NaN.

var v = median( -1.0 );
// returns NaN

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">

import randu from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@esm/index.mjs';
import round from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-round@esm/index.mjs';
import median from 'https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-dists-exponential-median@esm/index.mjs';

var lambda;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    lambda = randu() * 20.0;
    v = median( lambda );
    console.log( 'λ: %d, Median(X;λ): %d', lambda.toFixed( 4 ), v.toFixed( 4 ) );
}

</script>
</body>
</html>

C APIs

Usage

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

stdlib_base_dists_exponential_median( lambda )

Returns the median of an exponential distribution.

double out = stdlib_base_dists_exponential_median( 9.0 );
// returns ~0.077

The function accepts the following arguments:

  • lambda: [in] double rate parameter.
double stdlib_base_dists_exponential_median( const double lambda );

Examples

#include "stdlib/stats/base/dists/exponential/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 lambda;
    double y;
    int i;

    for ( i = 0; i < 25; i++ ) {
        lambda = random_uniform( 0.0, 20.0 );
        y = stdlib_base_dists_exponential_median( lambda );
        printf( "λ: %lf, Median(X;λ): %lf\n", lambda, y );
    }
}

Notice

This package is part of stdlib, a standard library 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

Chat

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.