https://github.com/stdlib-js/stats-strided-scumaxabs
Calculate the cumulative maximum absolute value of single-precision floating-point strided array elements.
https://github.com/stdlib-js/stats-strided-scumaxabs
abs absolute absolute-value accumulate cumulative domain extent extremes javascript math mathematics max maximum node node-js nodejs range statistics stats stdlib
Last synced: 6 months ago
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Calculate the cumulative maximum absolute value of single-precision floating-point strided array elements.
- Host: GitHub
- URL: https://github.com/stdlib-js/stats-strided-scumaxabs
- Owner: stdlib-js
- License: apache-2.0
- Created: 2025-03-29T22:28:01.000Z (6 months ago)
- Default Branch: main
- Last Pushed: 2025-03-29T23:21:01.000Z (6 months ago)
- Last Synced: 2025-03-29T23:23:40.829Z (6 months ago)
- Topics: abs, absolute, absolute-value, accumulate, cumulative, domain, extent, extremes, javascript, math, mathematics, max, maximum, node, node-js, nodejs, range, statistics, stats, stdlib
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 0 Bytes
- Stars: 0
- Watchers: 2
- 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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# scumaxabs
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Calculate the cumulative maximum absolute value of single-precision floating-point strided array elements.
## Installation
```bash
npm install @stdlib/stats-strided-scumaxabs
```
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 scumaxabs = require( '@stdlib/stats-strided-scumaxabs' );
```
#### scumaxabs( N, x, strideX, y, strideY )
Computes the cumulative maximum absolute value of single-precision floating-point strided array elements.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
var y = new Float32Array( x.length );
scumaxabs( x.length, x, 1, y, 1 );
// y => [ 1.0, 2.0, 2.0 ]
```
The function has the following parameters:
- **N**: number of indexed elements.
- **x**: input [`Float32Array`][@stdlib/array/float32].
- **strideX**: stride length for `x`.
- **y**: output [`Float32Array`][@stdlib/array/float32].
- **strideY**: stride length for `y`.
The `N` and stride parameters determine which elements in the strided arrays are accessed at runtime. For example, to compute the cumulative maximum absolute value of every other element in `x`,
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0 ] );
var y = new Float32Array( x.length );
var v = scumaxabs( 4, x, 2, y, 1 );
// y => [ 1.0, 2.0, 2.0, 4.0, 0.0, 0.0, 0.0, 0.0 ]
```
Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
// Initial arrays...
var x0 = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
var y0 = new Float32Array( x0.length );
// Create offset views...
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Float32Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element
scumaxabs( 4, x1, -2, y1, 1 );
// y0 => [ 0.0, 0.0, 0.0, 4.0, 4.0, 4.0, 4.0, 0.0 ]
```
#### scumaxabs.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )
Computes the cumulative maximum absolute value of single-precision floating-point strided array elements using alternative indexing semantics.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
var y = new Float32Array( x.length );
scumaxabs.ndarray( x.length, x, 1, 0, y, 1, 0 );
// y => [ 1.0, 2.0, 2.0 ]
```
The function has the following additional parameters:
- **offsetX**: starting index for `x`.
- **offsetY**: starting index for `y`.
While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, offset parameters support indexing semantics based on starting indices. For example, to calculate the cumulative maximum absolute value of every other element in `x` starting from the second element and to store in the last `N` elements of `y` starting from the last element
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
var y = new Float32Array( x.length );
scumaxabs.ndarray( 4, x, 2, 1, y, -1, y.length-1 );
// y => [ 0.0, 0.0, 0.0, 0.0, 4.0, 2.0, 2.0, 1.0 ]
```
## Notes
- If `N <= 0`, both functions return `y` unchanged.
## Examples
```javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var Float32Array = require( '@stdlib/array-float32' );
var scumaxabs = require( '@stdlib/stats-strided-scumaxabs' );
var x = discreteUniform( 10, -50, 50, {
'dtype': 'float32'
});
var y = new Float32Array( x.length );
console.log( x );
console.log( y );
scumaxabs( x.length, x, 1, y, -1 );
console.log( y );
```
* * *
## C APIs
### Usage
```c
#include "stdlib/stats/strided/scumaxabs.h"
```
#### stdlib_strided_scumaxabs( N, \*X, strideX, \*Y, strideY )
Computes the cumulative maximum absolute value of single-precision floating-point strided array elements.
```c
const float x[] = { 1.0f, 2.0f, -3.0f, 4.0f, -5.0f, 6.0f, 7.0f, 8.0f };
float y[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
stdlib_strided_scumaxabs( 4, x, 2, y, -2 );
```
The function accepts the following arguments:
- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[in] float*` input array.
- **strideX**: `[in] CBLAS_INT` stride length for `X`.
- **Y**: `[out] float*` output array.
- **strideY**: `[in] CBLAS_INT` stride length for `Y`.
```c
void stdlib_strided_scumaxabs( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, float *Y, const CBLAS_INT strideY );
```
#### stdlib_strided_scumaxabs_ndarray(N, \*X, strideX, offsetX, \*Y, strideY, offsetY )
Computes the cumulative maximum absolute value of single-precision floating-point strided array elements using alternative indexing semantics.
```c
const float x[] = { 1.0f, 2.0f, -3.0f, 4.0f, -5.0f, 6.0f, 7.0f, 8.0f };
float y[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
stdlib_strided_scumaxabs_ndarray( 4, x, 2, 0, y, -2, 0 );
```
The function accepts the following arguments:
- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[in] float*` input array.
- **strideX**: `[in] CBLAS_INT` stride length for `X`.
- **offsetX**: `[in] CBLAS_INT` starting index for `X`.
- **Y**: `[out] float*` output array.
- **strideY**: `[in] CBLAS_INT` stride length for `Y`.
- **offsetY**: `[in] CBLAS_INT` starting index for `Y`.
```c
void stdlib_strided_scumaxabs_ndarray( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, float *Y, const CBLAS_INT strideY, const CBLAS_INT offsetY );
```
### Examples
```c
#include "stdlib/stats/strided/scumaxabs.h"
#include
int main( void ) {
// Create strided arrays:
const float x[] = { 1.0f, 2.0f, -3.0f, 4.0f, -5.0f, 6.0f, 7.0f, 8.0f };
float y[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
// Specify the number of elements:
const int N = 4;
// Specify stride lengths:
const int strideX = 2;
const int strideY = -2;
// Compute the cumulative maximum absolute value:
stdlib_strided_scumaxabs( N, x, strideX, y, strideY );
// Print the result:
for ( int i = 0; i < 8; i++ ) {
printf( "y[ %d ] = %f\n", i, y[ i ] );
}
}
```
* * *
## See Also
- [`@stdlib/stats-base/cumaxabs`][@stdlib/stats/base/cumaxabs]: calculate the cumulative maximum absolute value of a strided array.
- [`@stdlib/stats-strided/dcumaxabs`][@stdlib/stats/strided/dcumaxabs]: calculate the cumulative maximum absolute value of double-precision floating-point strided array elements.
- [`@stdlib/stats-strided/scumax`][@stdlib/stats/strided/scumax]: calculate the cumulative maximum of single-precision floating-point strided array elements.
- [`@stdlib/stats-base/scuminabs`][@stdlib/stats/base/scuminabs]: calculate the cumulative minimum absolute value of single-precision floating-point strided array elements.
* * *
## 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-strided-scumaxabs.svg
[npm-url]: https://npmjs.org/package/@stdlib/stats-strided-scumaxabs
[test-image]: https://github.com/stdlib-js/stats-strided-scumaxabs/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/stats-strided-scumaxabs/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/stats-strided-scumaxabs/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/stats-strided-scumaxabs?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-strided-scumaxabs/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-strided-scumaxabs/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/stats-strided-scumaxabs/tree/umd
[umd-readme]: https://github.com/stdlib-js/stats-strided-scumaxabs/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/stats-strided-scumaxabs/tree/esm
[esm-readme]: https://github.com/stdlib-js/stats-strided-scumaxabs/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/stats-strided-scumaxabs/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-strided-scumaxabs/main/LICENSE
[@stdlib/array/float32]: https://github.com/stdlib-js/array-float32
[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
[@stdlib/stats/base/cumaxabs]: https://github.com/stdlib-js/stats-base-cumaxabs
[@stdlib/stats/strided/dcumaxabs]: https://github.com/stdlib-js/stats-strided-dcumaxabs
[@stdlib/stats/strided/scumax]: https://github.com/stdlib-js/stats-strided-scumax
[@stdlib/stats/base/scuminabs]: https://github.com/stdlib-js/stats-base-scuminabs