npm package: @stdlib/stats-base-dists-triangular-kurtosis
Description: Triangular distribution excess kurtosis.
Author: The Stdlib Authors
Latest version: 0.3.1

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# Kurtosis

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

> [Triangular][triangular-distribution] distribution [excess kurtosis][kurtosis].

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

The [excess kurtosis][kurtosis] for a [triangular][triangular-distribution] random variable with lower limit `a`, upper limit `b`, and mode `c` is

<!-- <equation class="equation" label="eq:triangular_kurtosis" align="center" raw="\operatorname{Kurt}\left( X \right) = -\frac{3}{5}" alt="Excess kurtosis for a triangular distribution."> -->

<div class="equation" align="center" data-raw-text="\operatorname{Kurt}\left( X \right) = -\frac{3}{5}" data-equation="eq:triangular_kurtosis">
    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@556e0ebc42f54244079cecc91c0883bb6c442244/lib/node_modules/@stdlib/stats/base/dists/triangular/kurtosis/docs/img/equation_triangular_kurtosis.svg" alt="Excess kurtosis for a triangular distribution.">
    <br>
</div>

<!-- </equation> -->

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

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

#### kurtosis( a, b, c )

Returns the [excess kurtosis][kurtosis] of a [triangular][triangular-distribution] distribution with minimum support `a`, maximum support`b`, and mode `c`.

```javascript
var v = kurtosis( 0.0, 1.0, 0.8 );
// returns -0.6

v = kurtosis( 4.0, 12.0, 5.0 );
// returns -0.6

v = kurtosis( 2.0, 8.0, 5.0 );
// returns -0.6
```

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

```javascript
var v = kurtosis( NaN, 4.0, 2.0 );
// returns NaN

v = kurtosis( 0.0, NaN, 2.0 );
// returns NaN

v = kurtosis( 0.0, 4.0, NaN );
// returns NaN
```

If provided parameters not satisfying `a <= c <= b`, the function returns `NaN`.

```javascript
var y = kurtosis( 1.0, 0.0, 1.5 );
// returns NaN

y = kurtosis( 0.0, 1.0, -1.0 );
// returns NaN

y = kurtosis( 0.0, -1.0, 0.5 );
// returns NaN
```

</section>

<!-- /.usage -->

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<section class="notes">

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-base-randu' );
var kurtosis = require( '@stdlib/stats-base-dists-triangular-kurtosis' );

var a;
var b;
var c;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    a = ( randu()*10.0 );
    b = ( randu()*10.0 ) + a;
    c = ( randu()*( b-a ) ) + a;
    v = kurtosis( a, b, c );
    console.log( 'a: %d, b: %d, c: %d, Kurt(X;a,b,c): %d', a.toFixed( 4 ), b.toFixed( 4 ), c.toFixed( 4 ), v.toFixed( 4 ) );
}
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

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<section class="intro">

</section>

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<section class="usage">

### Usage

```c
#include "stdlib/stats/base/dists/triangular/kurtosis.h"
```

#### stdlib_base_dists_triangular_kurtosis( a, b, c )

Returns the [excess kurtosis][kurtosis] of a [triangular][triangular-distribution] distribution with minimum support `a`, maximum support`b`, and mode `c`.

```c
double out = stdlib_base_dists_triangular_kurtosis( 0.0, 1.0, 0.8 );
// returns -0.6
```

The function accepts the following arguments:

-   **a**: `[in] double` minimum support.
-   **b**: `[in] double` maximum support.
-   **c**: `[in] double` mode.

```c
double stdlib_base_dists_triangular_kurtosis( const double a, const double b, const double c );
```

</section>

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<section class="notes">

</section>

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<section class="examples">

### Examples

```c
#include "stdlib/stats/base/dists/triangular/kurtosis.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 a;
    double b;
    double c;
    double v;
    int i;

    for ( i = 0; i < 25; i++ ) {
        a = random_uniform( 0.0, 10.0 );
        b = random_uniform( a, a+10.0 );
        c = random_uniform( a, b );
        v = stdlib_base_dists_triangular_kurtosis( a, b, c );
        printf( "a: %lf, b: %lf, c: %lf, Kurt(X;a,b,c): %lf\n", a, b, c, v );
    }
}
```

</section>

<!-- /.examples -->

</section>

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* * *

## 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].

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## License

See [LICENSE][stdlib-license].


## Copyright

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

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

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