npm package: @stdlib/stats-incr-mmidrange
Description: Compute a moving mid-range incrementally.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
  </summary>
  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
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</details>

# incrmmidrange

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

> Compute a moving [mid-range][mid-range] incrementally.

<section class="intro">

The [**mid-range**][mid-range], or **mid-extreme**, is the arithmetic mean of maximum and minimum values. Accordingly, the [mid-range][mid-range] is the midpoint of the [range][range] and a measure of central tendency.

</section>

<!-- /.intro -->

<section class="installation">

## Installation

```bash
npm install @stdlib/stats-incr-mmidrange
```

</section>

<section class="usage">

## Usage

```javascript
var incrmmidrange = require( '@stdlib/stats-incr-mmidrange' );
```

#### incrmmidrange( window )

Returns an accumulator `function` which incrementally computes a moving [mid-range][mid-range]. The `window` parameter defines the number of values over which to compute the moving [mid-range][mid-range].

```javascript
var accumulator = incrmmidrange( 3 );
```

#### accumulator( \[x] )

If provided an input value `x`, the accumulator function returns an updated [mid-range][mid-range]. If not provided an input value `x`, the accumulator function returns the current [mid-range][mid-range].

```javascript
var accumulator = incrmmidrange( 3 );

var mr = accumulator();
// returns null

// Fill the window...
mr = accumulator( 2.0 ); // [2.0]
// returns 2.0

mr = accumulator( 1.0 ); // [2.0, 1.0]
// returns 1.5

mr = accumulator( 3.0 ); // [2.0, 1.0, 3.0]
// returns 2.0

// Window begins sliding...
mr = accumulator( -7.0 ); // [1.0, 3.0, -7.0]
// returns -2.0

mr = accumulator( -5.0 ); // [3.0, -7.0, -5.0]
// returns -2.0

mr = accumulator();
// returns -2.0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   Input values are **not** type checked. If provided `NaN`, the accumulated value is `NaN` for **at least** `W-1` future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function.
-   As `W` values are needed to fill the window buffer, the first `W-1` returned values are calculated from smaller sample sizes. Until the window is full, each returned value is calculated from all provided values.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-base-randu' );
var incrmmidrange = require( '@stdlib/stats-incr-mmidrange' );

var accumulator;
var v;
var i;

// Initialize an accumulator:
accumulator = incrmmidrange( 5 );

// For each simulated datum, update the moving mid-range...
for ( i = 0; i < 100; i++ ) {
    v = randu() * 100.0;
    accumulator( v );
}
console.log( accumulator() );
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/stats-incr/mmean`][@stdlib/stats/incr/mmean]</span><span class="delimiter">: </span><span class="description">compute a moving arithmetic mean incrementally.</span>
-   <span class="package-name">[`@stdlib/stats-incr/mmax`][@stdlib/stats/incr/mmax]</span><span class="delimiter">: </span><span class="description">compute a moving maximum incrementally.</span>
-   <span class="package-name">[`@stdlib/stats-incr/mmin`][@stdlib/stats/incr/mmin]</span><span class="delimiter">: </span><span class="description">compute a moving minimum incrementally.</span>
-   <span class="package-name">[`@stdlib/stats-incr/mrange`][@stdlib/stats/incr/mrange]</span><span class="delimiter">: </span><span class="description">compute a moving range incrementally.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<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>

<!-- /.stdlib -->

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[stdlib]: https://github.com/stdlib-js/stdlib

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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/stats-incr-mmidrange/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-incr-mmidrange/blob/deno/README.md
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-incr-mmidrange/main/LICENSE

[range]: https://en.wikipedia.org/wiki/Range_%28statistics%29

[mid-range]: https://en.wikipedia.org/wiki/Mid-range

<!-- <related-links> -->

[@stdlib/stats/incr/mmean]: https://www.npmjs.com/package/@stdlib/stats-incr-mmean

[@stdlib/stats/incr/mmax]: https://www.npmjs.com/package/@stdlib/stats-incr-mmax

[@stdlib/stats/incr/mmin]: https://www.npmjs.com/package/@stdlib/stats-incr-mmin

[@stdlib/stats/incr/mrange]: https://www.npmjs.com/package/@stdlib/stats-incr-mrange

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</section>

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