@stdlib/stats-base-dists-triangular-ctor NPM

Triangular

Triangular distribution constructor.

Installation

npm install @stdlib/stats-base-dists-triangular-ctor

Usage

var Triangular = require( '@stdlib/stats-base-dists-triangular-ctor' );

Triangular( [a, b, c] )

Returns a triangular distribution object.

var triangular = new Triangular();

var mu = triangular.mean;
// returns 0.5

By default, a = 0.0, b = 1.0, and c = 0.5. To create a distribution having a different a (minimum support), b (maximum support), and c (mode), provide the corresponding arguments.

var triangular = new Triangular( 2.0, 4.0, 3.5 );

var mu = triangular.mean;
// returns ~3.167

triangular

An triangular distribution object has the following properties and methods...

Writable Properties

triangular.a

Minimum support of the distribution. a must be a number smaller than or equal to b and c.

var triangular = new Triangular();

var a = triangular.a;
// returns 0.0

triangular.a = 0.5;

a = triangular.a;
// returns 0.5

triangular.b

Maximum support of the distribution. b must be a number larger than or equal to a and c.

var triangular = new Triangular( 2.0, 4.0, 2.5 );

var b = triangular.b;
// returns 4.0

triangular.b = 3.0;

b = triangular.b;
// returns 3.0

triangular.c

Mode of the distribution. c must be a number larger than or equal to a and smaller than or equal to b.

var triangular = new Triangular( 2.0, 5.0, 4.0 );

var c = triangular.c;
// returns 4.0

triangular.c = 3.0;

c = triangular.c;
// returns 3.0

Computed Properties

Triangular.prototype.entropy

Returns the differential entropy.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var entropy = triangular.entropy;
// returns ~1.886

Triangular.prototype.kurtosis

Returns the excess kurtosis.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var kurtosis = triangular.kurtosis;
// returns -0.6

Triangular.prototype.mean

Returns the expected value.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var mu = triangular.mean;
// returns ~8.667

Triangular.prototype.median

Returns the median.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var median = triangular.median;
// returns ~8.899

Triangular.prototype.mode

Returns the mode.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var mode = triangular.mode;
// returns 10.0

Triangular.prototype.skewness

Returns the skewness.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var skewness = triangular.skewness;
// returns ~-0.422

Triangular.prototype.stdev

Returns the standard deviation.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var s = triangular.stdev;
// returns ~1.7

Triangular.prototype.variance

Returns the variance.

var triangular = new Triangular( 4.0, 12.0, 10.0 );

var s2 = triangular.variance;
// returns ~2.889

Methods

Triangular.prototype.cdf( x )

Evaluates the cumulative distribution function (CDF).

var triangular = new Triangular( 2.0, 4.0, 3.0 );

var y = triangular.cdf( 2.5 );
// returns 0.125

Triangular.prototype.logcdf( x )

Evaluates the natural logarithm of the cumulative distribution function (CDF).

var triangular = new Triangular( 2.0, 4.0, 3.0 );

var y = triangular.logcdf( 2.5 );
// returns ~-2.079

Triangular.prototype.logpdf( x )

Evaluates the natural logarithm of the probability density function (PDF).

var triangular = new Triangular( 2.0, 4.0, 3.0 );

var y = triangular.logpdf( 2.5 );
// returns ~-0.693

Triangular.prototype.pdf( x )

Evaluates the probability density function (PDF).

var triangular = new Triangular( 2.0, 4.0, 3.0 );

var y = triangular.pdf( 2.5 );
// returns 0.5

Triangular.prototype.quantile( p )

Evaluates the quantile function at probability p.

var triangular = new Triangular( 2.0, 4.0, 3.0 );

var y = triangular.quantile( 0.5 );
// returns 3.0

y = triangular.quantile( 1.9 );
// returns NaN

Examples

var Triangular = require( '@stdlib/stats-base-dists-triangular-ctor' );

var triangular = new Triangular( 2.0, 4.0, 3.0 );

var mu = triangular.mean;
// returns 3.0

var median = triangular.median;
// returns 3.0

var s2 = triangular.variance;
// returns ~0.167

var y = triangular.cdf( 2.5 );
// returns 0.125

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.