@stdlib/stats-base-dists-weibull-cdf
v0.2.2
Published
Weibull distribution cumulative distribution function (CDF).
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Cumulative Distribution Function
Weibull distribution cumulative distribution function.
The cumulative distribution function for a Weibull random variable is
where lambda > 0
is the shape parameter and k > 0
is the scale parameter.
Installation
npm install @stdlib/stats-base-dists-weibull-cdf
Usage
var cdf = require( '@stdlib/stats-base-dists-weibull-cdf' );
cdf( x, k, lambda )
Evaluates the cumulative distribution function (CDF) for a Weibull distribution with shape parameter k
and scale parameter lambda
.
var y = cdf( 2.0, 1.0, 0.5 );
// returns ~0.982
y = cdf( 0.0, 1.0, 0.5 );
// returns 0.0
y = cdf( -Infinity, 4.0, 2.0 );
// returns 0.0
y = cdf( +Infinity, 4.0, 2.0 );
// returns 1.0
If provided NaN
as any argument, the function returns NaN
.
var y = cdf( NaN, 1.0, 1.0 );
// returns NaN
y = cdf( 0.0, NaN, 1.0 );
// returns NaN
y = cdf( 0.0, 1.0, NaN );
// returns NaN
If provided k <= 0
, the function returns NaN
.
var y = cdf( 2.0, 0.5, -1.0 );
// returns NaN
y = cdf( 2.0, 0.5, 0.0 );
// returns NaN
If provided lambda <= 0
, the function returns NaN
.
var y = cdf( 2.0, 0.5, -1.0 );
// returns NaN
y = cdf( 2.0, 0.5, 0.0 );
// returns NaN
cdf.factory( k, lambda )
Returns a function for evaluating the cumulative distribution function of a Weibull distribution with shape parameter k
and scale parameter lambda
.
var mycdf = cdf.factory( 2.0, 10.0 );
var y = mycdf( 10.0 );
// returns ~0.632
y = mycdf( 8.0 );
// returns ~0.473
Examples
var randu = require( '@stdlib/random-base-randu' );
var cdf = require( '@stdlib/stats-base-dists-weibull-cdf' );
var lambda;
var k;
var x;
var y;
var i;
for ( i = 0; i < 10; i++ ) {
x = randu() * 10.0;
lambda = randu() * 10.0;
k = randu() * 10.0;
y = cdf( x, lambda, k );
console.log( 'x: %d, k: %d, λ: %d, F(x;k,λ): %d', x, k, lambda, y );
}
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.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.