https://github.com/stdlib-js/stats-base-nanmskmin
Calculate the minimum value of a strided array according to a mask, ignoring NaN values.
https://github.com/stdlib-js/stats-base-nanmskmin
domain extent extremes javascript mask masked masked-array math mathematics min minimum node node-js nodejs range statistics stats stdlib strided strided-array
Last synced: 6 months ago
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Calculate the minimum value of a strided array according to a mask, ignoring NaN values.
- Host: GitHub
- URL: https://github.com/stdlib-js/stats-base-nanmskmin
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-14T13:48:12.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2024-12-01T04:37:47.000Z (11 months ago)
- Last Synced: 2025-03-06T21:46:00.281Z (7 months ago)
- Topics: domain, extent, extremes, javascript, mask, masked, masked-array, math, mathematics, min, minimum, node, node-js, nodejs, range, statistics, stats, stdlib, strided, strided-array
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 624 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
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# nanmskmin
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Calculate the minimum value of a strided array according to a mask, ignoring `NaN` values.
## Installation
```bash
npm install @stdlib/stats-base-nanmskmin
```
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 nanmskmin = require( '@stdlib/stats-base-nanmskmin' );
```
#### nanmskmin( N, x, strideX, mask, strideMask )
Computes the minimum value of a strided array `x` according to a `mask`, ignoring `NaN` values.
```javascript
var x = [ 1.0, -2.0, -4.0, 2.0, NaN ];
var mask = [ 0, 0, 1, 0, 0 ];
var v = nanmskmin( x.length, x, 1, mask, 1 );
// returns -2.0
```
The function has the following parameters:
- **N**: number of indexed elements.
- **x**: input [`Array`][mdn-array] or [`typed array`][mdn-typed-array].
- **strideX**: index increment for `x`.
- **mask**: mask [`Array`][mdn-array] or [`typed array`][mdn-typed-array]. If a `mask` array element is `0`, the corresponding element in `x` is considered valid and **included** in computation. If a `mask` array element is `1`, the corresponding element in `x` is considered invalid/missing and **excluded** from computation.
- **strideMask**: index increment for `mask`.
The `N` and `stride` parameters determine which elements are accessed at runtime. For example, to compute the minimum value of every other element in `x`,
```javascript
var floor = require( '@stdlib/math-base-special-floor' );
var x = [ 1.0, 2.0, -7.0, -2.0, 4.0, 3.0, -5.0, -6.0 ];
var mask = [ 0, 0, 0, 0, 0, 0, 1, 1 ];
var N = floor( x.length / 2 );
var v = nanmskmin( N, x, 2, mask, 2 );
// returns -7.0
```
Note that indexing is relative to the first index. To introduce offsets, use [`typed array`][mdn-typed-array] views.
```javascript
var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );
var floor = require( '@stdlib/math-base-special-floor' );
var x0 = new Float64Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, 5.0, 6.0 ] );
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var mask0 = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
var mask1 = new Uint8Array( mask0.buffer, mask0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var N = floor( x0.length / 2 );
var v = nanmskmin( N, x1, 2, mask1, 2 );
// returns -2.0
```
#### nanmskmin.ndarray( N, x, strideX, offsetX, mask, strideMask, offsetMask )
Computes the minimum value of a strided array according to a `mask`, ignoring `NaN` values and using alternative indexing semantics.
```javascript
var x = [ 1.0, -2.0, -4.0, 2.0, NaN ];
var mask = [ 0, 0, 1, 0, 0 ];
var v = nanmskmin.ndarray( x.length, x, 1, 0, mask, 1, 0 );
// returns -2.0
```
The function has the following additional parameters:
- **offsetX**: starting index for `x`.
- **offsetMask**: starting index for `mask`.
While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the `offset` parameter supports indexing semantics based on a starting index. For example, to calculate the minimum value for every other value in `x` starting from the second value
```javascript
var floor = require( '@stdlib/math-base-special-floor' );
var x = [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, -5.0, -6.0 ];
var mask = [ 0, 0, 0, 0, 0, 0, 1, 1 ];
var N = floor( x.length / 2 );
var v = nanmskmin.ndarray( N, x, 2, 1, mask, 2, 1 );
// returns -2.0
```
## Notes
- If `N <= 0`, both functions return `NaN`.
- Depending on the environment, the typed versions ([`dnanmskmin`][@stdlib/stats/base/dnanmskmin], [`snanmskmin`][@stdlib/stats/base/snanmskmin], etc.) are likely to be significantly more performant.
## Examples
```javascript
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );
var nanmskmin = require( '@stdlib/stats-base-nanmskmin' );
var mask;
var x;
var i;
x = new Float64Array( 10 );
mask = new Uint8Array( x.length );
for ( i = 0; i < x.length; i++ ) {
if ( randu() < 0.2 ) {
mask[ i ] = 1;
} else {
mask[ i ] = 0;
}
if ( randu() < 0.1 ) {
x[ i ] = NaN;
} else {
x[ i ] = round( (randu()*100.0) - 50.0 );
}
}
console.log( x );
console.log( mask );
var v = nanmskmin( x.length, x, 1, mask, 1 );
console.log( v );
```
* * *
## See Also
- [`@stdlib/stats-base/dnanmskmin`][@stdlib/stats/base/dnanmskmin]: calculate the minimum value of a double-precision floating-point strided array according to a mask, ignoring NaN values.
- [`@stdlib/stats-base/mskmin`][@stdlib/stats/base/mskmin]: calculate the minimum value of a strided array according to a mask.
- [`@stdlib/stats-base/nanmin`][@stdlib/stats/base/nanmin]: calculate the minimum value of a strided array, ignoring NaN values.
- [`@stdlib/stats-base/nanmskmax`][@stdlib/stats/base/nanmskmax]: calculate the maximum value of a strided array according to a mask, ignoring NaN values.
- [`@stdlib/stats-base/snanmskmin`][@stdlib/stats/base/snanmskmin]: calculate the minimum value of a single-precision floating-point strided array according to a mask, ignoring NaN values.
* * *
## 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 © 2016-2024. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/stats-base-nanmskmin.svg
[npm-url]: https://npmjs.org/package/@stdlib/stats-base-nanmskmin
[test-image]: https://github.com/stdlib-js/stats-base-nanmskmin/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/stats-base-nanmskmin/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/stats-base-nanmskmin/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/stats-base-nanmskmin?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-base-nanmskmin/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-base-nanmskmin/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/stats-base-nanmskmin/tree/umd
[umd-readme]: https://github.com/stdlib-js/stats-base-nanmskmin/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/stats-base-nanmskmin/tree/esm
[esm-readme]: https://github.com/stdlib-js/stats-base-nanmskmin/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/stats-base-nanmskmin/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-base-nanmskmin/main/LICENSE
[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
[@stdlib/stats/base/dnanmskmin]: https://github.com/stdlib-js/stats-base-dnanmskmin
[@stdlib/stats/base/mskmin]: https://github.com/stdlib-js/stats-base-mskmin
[@stdlib/stats/base/nanmin]: https://github.com/stdlib-js/stats-base-nanmin
[@stdlib/stats/base/nanmskmax]: https://github.com/stdlib-js/stats-base-nanmskmax
[@stdlib/stats/base/snanmskmin]: https://github.com/stdlib-js/stats-base-snanmskmin