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https://github.com/stdlib-js/blas-ext-base-sapxsumkbn
Add a constant to each single-precision floating-point strided array element and compute the sum using an improved Kahan–Babuška algorithm.
https://github.com/stdlib-js/blas-ext-base-sapxsumkbn
blas compensated extended javascript kahan kbn math mathematics node node-js nodejs statistics stats stdlib strided strided-array sum summation total typed
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Add a constant to each single-precision floating-point strided array element and compute the sum using an improved Kahan–Babuška algorithm.
- Host: GitHub
- URL: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-15T18:05:10.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2024-11-01T09:54:08.000Z (17 days ago)
- Last Synced: 2024-11-09T10:58:32.311Z (9 days ago)
- Topics: blas, compensated, extended, javascript, kahan, kbn, math, mathematics, node, node-js, nodejs, statistics, stats, stdlib, strided, strided-array, sum, summation, total, typed
- Language: JavaScript
- Homepage:
- Size: 632 KB
- Stars: 2
- 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!
# sapxsumkbn
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Add a constant to each single-precision floating-point strided array element and compute the sum using an improved Kahan–Babuška algorithm.
## Installation
```bash
npm install @stdlib/blas-ext-base-sapxsumkbn
```
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 sapxsumkbn = require( '@stdlib/blas-ext-base-sapxsumkbn' );
```
#### sapxsumkbn( N, alpha, x, stride )
Adds a constant to each single-precision floating-point strided array element and computes the sum using an improved Kahan–Babuška algorithm.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
var v = sapxsumkbn( 3, 5.0, x, 1 );
// returns 16.0
```
The function has the following parameters:
- **N**: number of indexed elements.
- **alpha**: scalar constant.
- **x**: input [`Float32Array`][@stdlib/array/float32].
- **stride**: index increment for `x`.
The `N` and `stride` parameters determine which elements in the strided array are accessed at runtime. For example, to access every other element in the strided array,
```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 v = sapxsumkbn( 4, 5.0, x, 2 );
// returns 25.0
```
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' );
var x0 = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var v = sapxsumkbn( 4, 5.0, x1, 2 );
// returns 25.0
```
#### sapxsumkbn.ndarray( N, alpha, x, stride, offset )
Adds a constant to each single-precision floating-point strided array element and computes the sum using an improved Kahan–Babuška algorithm and alternative indexing semantics.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
var v = sapxsumkbn.ndarray( 3, 5.0, x, 1, 0 );
// returns 16.0
```
The function has the following additional parameters:
- **offset**: starting index for `x`.
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 access every other value in the strided array starting from the second value
```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 v = sapxsumkbn.ndarray( 4, 5.0, x, 2, 1 );
// returns 25.0
```
## Notes
- If `N <= 0`, both functions return `0.0`.
## Examples
```javascript
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var filledarrayBy = require( '@stdlib/array-filled-by' );
var sapxsumkbn = require( '@stdlib/blas-ext-base-sapxsumkbn' );
var x = filledarrayBy( 10, 'float32', discreteUniform( 0, 100 ) );
console.log( x );
var v = sapxsumkbn( x.length, 5.0, x, 1 );
console.log( v );
```
* * *
## References
- Neumaier, Arnold. 1974. "Rounding Error Analysis of Some Methods for Summing Finite Sums." _Zeitschrift Für Angewandte Mathematik Und Mechanik_ 54 (1): 39–51. doi:[10.1002/zamm.19740540106][@neumaier:1974a].
* * *
## See Also
- [`@stdlib/blas-ext/base/dapxsumkbn`][@stdlib/blas/ext/base/dapxsumkbn]: adds a constant to each double-precision floating-point strided array element and computes the sum using an improved Kahan–Babuška algorithm.
- [`@stdlib/blas-ext/base/gapxsumkbn`][@stdlib/blas/ext/base/gapxsumkbn]: adds a constant to each strided array element and computes the sum using an improved Kahan–Babuška algorithm.
- [`@stdlib/blas-ext/base/sapxsum`][@stdlib/blas/ext/base/sapxsum]: adds a constant to each single-precision floating-point strided array element and computes the sum.
- [`@stdlib/blas-ext/base/ssumkbn`][@stdlib/blas/ext/base/ssumkbn]: calculate the sum of single-precision floating-point strided array elements using an improved Kahan–Babuška algorithm.
* * *
## 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/blas-ext-base-sapxsumkbn.svg
[npm-url]: https://npmjs.org/package/@stdlib/blas-ext-base-sapxsumkbn
[test-image]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/blas-ext-base-sapxsumkbn/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/blas-ext-base-sapxsumkbn?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/blas-ext-base-sapxsumkbn/tree/deno
[deno-readme]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/tree/umd
[umd-readme]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/tree/esm
[esm-readme]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumkbn/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/blas-ext-base-sapxsumkbn/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
[@neumaier:1974a]: https://doi.org/10.1002/zamm.19740540106
[@stdlib/blas/ext/base/dapxsumkbn]: https://github.com/stdlib-js/blas-ext-base-dapxsumkbn
[@stdlib/blas/ext/base/gapxsumkbn]: https://github.com/stdlib-js/blas-ext-base-gapxsumkbn
[@stdlib/blas/ext/base/sapxsum]: https://github.com/stdlib-js/blas-ext-base-sapxsum
[@stdlib/blas/ext/base/ssumkbn]: https://github.com/stdlib-js/blas-ext-base-ssumkbn