npm package: @stdlib/stats-base-dists-triangular-ctor
Description: Triangular distribution constructor.
Author: The Stdlib Authors
Latest version: 0.2.3

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# Triangular

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Triangular distribution constructor.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

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

#### Triangular( \[a, b, c] )

Returns a [triangular][triangular-distribution] distribution object.

```javascript
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.

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

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

* * *

## triangular

An [triangular][triangular-distribution] 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`.

```javascript
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`.

```javascript
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`.

```javascript
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][entropy].

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

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

#### Triangular.prototype.kurtosis

Returns the [excess kurtosis][kurtosis].

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

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

#### Triangular.prototype.mean

Returns the [expected value][expected-value].

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

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

#### Triangular.prototype.median

Returns the [median][median].

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

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

#### Triangular.prototype.mode

Returns the [mode][mode].

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

var mode = triangular.mode;
// returns 10.0
```

#### Triangular.prototype.skewness

Returns the [skewness][skewness].

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

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

#### Triangular.prototype.stdev

Returns the [standard deviation][standard-deviation].

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

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

#### Triangular.prototype.variance

Returns the [variance][variance].

```javascript
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] (CDF).

```javascript
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] (CDF).

```javascript
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] (PDF).

```javascript
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] (PDF).

```javascript
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][quantile-function] at probability `p`.

```javascript
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
```

</section>

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<section class="notes">

</section>

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<!-- Package usage examples. -->

* * *

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
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
```

</section>

<!-- /.examples -->

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<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-base-dists-triangular-ctor/main/LICENSE

[triangular-distribution]: https://en.wikipedia.org/wiki/Triangular_distribution

[cdf]: https://en.wikipedia.org/wiki/Cumulative_distribution_function

[pdf]: https://en.wikipedia.org/wiki/Probability_density_function

[quantile-function]: https://en.wikipedia.org/wiki/Quantile_function

[entropy]: https://en.wikipedia.org/wiki/Entropy_%28information_theory%29

[expected-value]: https://en.wikipedia.org/wiki/Expected_value

[kurtosis]: https://en.wikipedia.org/wiki/Kurtosis

[median]: https://en.wikipedia.org/wiki/Median

[mode]: https://en.wikipedia.org/wiki/Mode_%28statistics%29

[skewness]: https://en.wikipedia.org/wiki/Skewness

[standard-deviation]: https://en.wikipedia.org/wiki/Standard_deviation

[variance]: https://en.wikipedia.org/wiki/Variance

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