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

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# Degenerate

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

> Degenerate distribution constructor.

<!-- 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">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

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

#### Degenerate( \[mu] )

Returns a [Degenerate][degenerate-distribution] distribution object.

```javascript
var degenerate = new Degenerate();

var mean = degenerate.mean;
// returns 0.0
```

By default, `mu = 0.0`. To create a distribution having a different mean value `mu`, provide a parameter value.

```javascript
var degenerate = new Degenerate( 20.0 );

var mean = degenerate.mean;
// returns 20.0
```

* * *

## degenerate

A [Degenerate][degenerate-distribution] distribution object has the following properties and methods...

### Writable Properties

#### degenerate.mu

Constant value of the distribution.

```javascript
var degenerate = new Degenerate( 2.0 );

var mu = degenerate.mu;
// returns 2.0

degenerate.mu = -2.0;

mu = degenerate.mu;
// returns -2.0
```

* * *

### Computed Properties

#### Degenerate.prototype.entropy

Returns the [differential entropy][entropy].

```javascript
var degenerate = new Degenerate( 4.0 );

var entropy = degenerate.entropy;
// returns 0.0
```

#### Degenerate.prototype.mean

Returns the [mean][expected-value].

```javascript
var degenerate = new Degenerate( 10.0 );

var mu = degenerate.mean;
// returns 10.0
```

#### Degenerate.prototype.median

Returns the [median][median].

```javascript
var degenerate = new Degenerate( 10.0 );

var median = degenerate.median;
// returns 10.0
```

#### Degenerate.prototype.mode

Returns the [mode][mode].

```javascript
var degenerate = new Degenerate( 10.0 );

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

#### Degenerate.prototype.stdev

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

```javascript
var degenerate = new Degenerate( 4.0 );

var s = degenerate.stdev;
// returns 0.0
```

#### Degenerate.prototype.variance

Returns the [variance][variance].

```javascript
var degenerate = new Degenerate( 4.0 );

var s2 = degenerate.variance;
// returns 0.0
```

* * *

### Methods

#### Degenerate.prototype.cdf( x )

Evaluates the [cumulative distribution function][cdf] (CDF).

```javascript
var degenerate = new Degenerate( 0.2 );

var y = degenerate.cdf( 0.5 );
// returns 1.0
```

#### Degenerate.prototype.logcdf( x )

Evaluates the natural logarithm of the [cumulative distribution function][cdf] (logCDF).

```javascript
var degenerate = new Degenerate( 0.2 );

var y = degenerate.logcdf( 0.5 );
// returns 0.0
```

#### Degenerate.prototype.logpdf( x )

Evaluates the natural logarithm of the [probability density function][pdf] (logPDF).

```javascript
var degenerate = new Degenerate( 10.0 );

var y = degenerate.logpdf( 9.0 );
// returns -Infinity

y = degenerate.logpdf( 10.0 );
// returns Infinity
```

#### Degenerate.prototype.logpmf( x )

Evaluates the natural logarithm of the [probability mass function][pmf] (logPMF).

```javascript
var degenerate = new Degenerate( 10.0 );

var y = degenerate.logpmf( 9.0 );
// returns -Infinity

y = degenerate.logpmf( 10.0 );
// returns 0.0
```

#### Degenerate.prototype.mgf( t )

Evaluates the [moment-generating function][mgf] (MGF).

```javascript
var degenerate = new Degenerate( 10.0 );

var y = degenerate.mgf( 0.1 );
// returns ~2.718
```

#### Degenerate.prototype.pdf( x )

Evaluates the [probability density function][pdf] (PDF).

```javascript
var degenerate = new Degenerate( 10.0 );

var y = degenerate.pdf( 2.0 );
// returns 0.0

y = degenerate.pdf( 10.0 );
// returns +Infinity
```

#### Degenerate.prototype.pmf( x )

Evaluates the [probability mass function][pmf] (PMF).

```javascript
var degenerate = new Degenerate( 10.0 );

var y = degenerate.pmf( 2.0 );
// returns 0.0

y = degenerate.pmf( 10.0 );
// returns 1.0
```

#### Degenerate.prototype.quantile( p )

Evaluates the [quantile function][quantile-function] at probability `p`.

```javascript
var degenerate = new Degenerate( 10.0 );

var y = degenerate.quantile( 0.5 );
// returns 10.0

y = degenerate.quantile( 0.9 );
// returns 10.0
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

* * *

<section class="examples">

## Examples

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

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

var degenerate = new Degenerate( 0.5 );

var mu = degenerate.mean;
// returns 0.5

var s2 = degenerate.variance;
// returns 0.0

var y = degenerate.cdf( 2.0 );
// returns 1.0
```

</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].

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

[degenerate-distribution]: https://en.wikipedia.org/wiki/Degenerate_distribution

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

[mgf]: https://en.wikipedia.org/wiki/Moment-generating_function

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

[pmf]: https://en.wikipedia.org/wiki/Probability_mass_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

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

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

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

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

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