# @stdlib/stats-base-dists-rayleigh-cdf

0.2.2 • Public • Published

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# Cumulative Distribution Function

Rayleigh distribution cumulative distribution function.

The cumulative distribution function for a Rayleigh random variable is

where sigma > 0 is the scale parameter.

## Installation

npm install @stdlib/stats-base-dists-rayleigh-cdf

## Usage

var cdf = require( '@stdlib/stats-base-dists-rayleigh-cdf' );

#### cdf( x, sigma )

Evaluates the cumulative distribution function for a Rayleigh distribution with scale parameter sigma.

var y = cdf( 2.0, 3.0 );
// returns ~0.199

y = cdf( 1.0, 2.0 );
// returns ~0.118

y = cdf( -1.0, 4.0 );
// returns 0.0

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

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

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

If provided sigma < 0, the function returns NaN.

var y = cdf( 2.0, -1.0 );
// returns NaN

If provided sigma = 0, the function evaluates the CDF of a degenerate distribution centered at 0.

var y = cdf( -2.0, 0.0 );
// returns 0.0

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

y = cdf( 2.0, 0.0 );
// returns 1.0

#### cdf.factory( sigma )

Returns a function for evaluating the cumulative distribution function of a Rayleigh distribution with parameter sigma (scale parameter).

var myCDF = cdf.factory( 0.5 );
y = myCDF( 1.0 );
// returns ~0.865

y = myCDF( 0.5 );
// returns ~0.393

## Examples

var randu = require( '@stdlib/random-base-randu' );
var cdf = require( '@stdlib/stats-base-dists-rayleigh-cdf' );

var sigma;
var x;
var y;
var i;

for ( i = 0; i < 10; i++ ) {
x = randu() * 10.0;
sigma = randu() * 10.0;
y = cdf( x, sigma );
console.log( 'x: %d, σ: %d, F(x;σ): %d', x.toFixed( 4 ), sigma.toFixed( 4 ), y.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.

## Package Sidebar

### Install

npm i @stdlib/stats-base-dists-rayleigh-cdf

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