https://github.com/stdlib-js/stats-incr-msumabs2
Compute a moving sum of squared absolute values incrementally.
https://github.com/stdlib-js/stats-incr-msumabs2
absolute accumulator incremental javascript math mathematics moving moving-sum node node-js nodejs rolling sliding sliding-window statistics stats stdlib sum total window
Last synced: about 2 months ago
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Compute a moving sum of squared absolute values incrementally.
- Host: GitHub
- URL: https://github.com/stdlib-js/stats-incr-msumabs2
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-15T16:11:30.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2025-02-24T02:06:55.000Z (3 months ago)
- Last Synced: 2025-04-10T00:43:38.205Z (about 2 months ago)
- Topics: absolute, accumulator, incremental, javascript, math, mathematics, moving, moving-sum, node, node-js, nodejs, rolling, sliding, sliding-window, statistics, stats, stdlib, sum, total, window
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 950 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
About stdlib...
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To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
# incrmsumabs2
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Compute a moving sum of squared absolute values incrementally.
For a window of size `W`, the moving sum of squared absolute values is defined as
```math
s = \sum_{i=0}^{W-1} x_i^2
```
## Installation
```bash
npm install @stdlib/stats-incr-msumabs2
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var incrmsumabs2 = require( '@stdlib/stats-incr-msumabs2' );
```
#### incrmsumabs2( window )
Returns an accumulator `function` which incrementally computes a moving sum of squared absolute values. The `window` parameter defines the number of values over which to compute the moving sum.
```javascript
var accumulator = incrmsumabs2( 3 );
```
#### accumulator( \[x] )
If provided an input value `x`, the accumulator function returns an updated sum. If not provided an input value `x`, the accumulator function returns the current sum.
```javascript
var accumulator = incrmsumabs2( 3 );
var sum = accumulator();
// returns null
// Fill the window...
sum = accumulator( 2.0 ); // [2.0]
// returns 4.0
sum = accumulator( -1.0 ); // [2.0, -1.0]
// returns 5.0
sum = accumulator( 3.0 ); // [2.0, -1.0, 3.0]
// returns 14.0
// Window begins sliding...
sum = accumulator( -7.0 ); // [-1.0, 3.0, -7.0]
// returns 59.0
sum = accumulator( -5.0 ); // [3.0, -7.0, -5.0]
// returns 83.0
sum = accumulator();
// returns 83.0
```
## Notes
- Input values are **not** type checked. If provided `NaN` or a value which, when used in computations, results in `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.
## Examples
```javascript
var randu = require( '@stdlib/random-base-randu' );
var incrmsumabs2 = require( '@stdlib/stats-incr-msumabs2' );
var accumulator;
var v;
var i;
// Initialize an accumulator:
accumulator = incrmsumabs2( 5 );
// For each simulated datum, update the moving sum...
for ( i = 0; i < 100; i++ ) {
v = ( randu()*100.0 ) - 50.0;
accumulator( v );
}
console.log( accumulator() );
```
* * *
## See Also
- [`@stdlib/stats-incr/mmeanabs2`][@stdlib/stats/incr/mmeanabs2]: compute a moving arithmetic mean of squared absolute values incrementally.
- [`@stdlib/stats-incr/msumabs`][@stdlib/stats/incr/msumabs]: compute a moving sum of absolute values incrementally.
- [`@stdlib/stats-incr/sumabs`][@stdlib/stats/incr/sumabs]: compute a sum of absolute values incrementally.
- [`@stdlib/stats-incr/sumabs2`][@stdlib/stats/incr/sumabs2]: compute a sum of squared absolute values incrementally.
* * *
## 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 © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/stats-incr-msumabs2.svg
[npm-url]: https://npmjs.org/package/@stdlib/stats-incr-msumabs2
[test-image]: https://github.com/stdlib-js/stats-incr-msumabs2/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/stats-incr-msumabs2/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/stats-incr-msumabs2/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/stats-incr-msumabs2?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[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-msumabs2/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-incr-msumabs2/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/stats-incr-msumabs2/tree/umd
[umd-readme]: https://github.com/stdlib-js/stats-incr-msumabs2/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/stats-incr-msumabs2/tree/esm
[esm-readme]: https://github.com/stdlib-js/stats-incr-msumabs2/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/stats-incr-msumabs2/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-incr-msumabs2/main/LICENSE
[@stdlib/stats/incr/mmeanabs2]: https://github.com/stdlib-js/stats-incr-mmeanabs2
[@stdlib/stats/incr/msumabs]: https://github.com/stdlib-js/stats-incr-msumabs
[@stdlib/stats/incr/sumabs]: https://github.com/stdlib-js/stats-incr-sumabs
[@stdlib/stats/incr/sumabs2]: https://github.com/stdlib-js/stats-incr-sumabs2