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https://github.com/stdlib-js/blas-ext-base-sapxsumors

Adds a constant to each single-precision floating-point strided array element and computes the sum using ordinary recursive summation.
https://github.com/stdlib-js/blas-ext-base-sapxsumors

array blas extended float32 javascript math mathematics node node-js nodejs ors statistics stats stdlib strided strided-array sum summation total typed

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Adds a constant to each single-precision floating-point strided array element and computes the sum using ordinary recursive summation.

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README 

        



  

    About stdlib...

  

  
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# sapxsumors



[![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 ordinary recursive summation.



## Installation



```bash

npm install @stdlib/blas-ext-base-sapxsumors

```



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 sapxsumors = require( '@stdlib/blas-ext-base-sapxsumors' );

```



#### sapxsumors( N, alpha, x, stride )



Adds a constant to each single-precision floating-point strided array element and computes the sum using ordinary recursive summation.



```javascript

var Float32Array = require( '@stdlib/array-float32' );



var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );



var v = sapxsumors( x.length, 5.0, x, 1 );

// returns 16.0

```



The function has the following parameters:



-   **N**: number of indexed elements.

-   **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 `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 v = sapxsumors( 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 = sapxsumors( 4, 5.0, x1, 2 );

// returns 25.0

```



#### sapxsumors.ndarray( N, alpha, x, stride, offset )



Adds a constant to each single-precision floating-point strided array element and computes the sum using ordinary recursive summation and alternative indexing semantics.



```javascript

var Float32Array = require( '@stdlib/array-float32' );



var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );



var v = sapxsumors.ndarray( x.length, 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 `x` 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 = sapxsumors.ndarray( 4, 5.0, x, 2, 1 );

// returns 25.0

```



## Notes



-   If `N <= 0`, both functions return `0.0`.

-   Ordinary recursive summation (i.e., a "simple" sum) is performant, but can incur significant numerical error. If performance is paramount and error tolerated, using ordinary recursive summation is acceptable; in all other cases, exercise due caution.



## Examples



```javascript

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;

var filledarrayBy = require( '@stdlib/array-filled-by' );

var Float32Array = require( '@stdlib/array-float32' );

var sapxsumors = require( '@stdlib/blas-ext-base-sapxsumors' );



var x = filledarrayBy( 10, 'float32', discreteUniform( 0, 100 ) );

console.log( x );



var v = sapxsumors( x.length, 5.0, x, 1 );

console.log( v );

```



* * *



## See Also



-   [`@stdlib/blas-ext/base/dapxsumors`][@stdlib/blas/ext/base/dapxsumors]: adds a constant to each double-precision floating-point strided array element and computes the sum using ordinary recursive summation.

-   [`@stdlib/blas-ext/base/gapxsumors`][@stdlib/blas/ext/base/gapxsumors]: adds a constant to each strided array element and computes the sum using ordinary recursive summation.

-   [`@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/ssumors`][@stdlib/blas/ext/base/ssumors]: calculate the sum of single-precision floating-point strided array elements using ordinary recursive summation.



* * *



## 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-sapxsumors.svg

[npm-url]: https://npmjs.org/package/@stdlib/blas-ext-base-sapxsumors



[test-image]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/actions/workflows/test.yml/badge.svg?branch=main

[test-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/actions/workflows/test.yml?query=branch:main



[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/blas-ext-base-sapxsumors/main.svg

[coverage-url]: https://codecov.io/github/stdlib-js/blas-ext-base-sapxsumors?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-sapxsumors/tree/deno

[deno-readme]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/tree/umd

[umd-readme]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/tree/esm

[esm-readme]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/blas-ext-base-sapxsumors/blob/main/branches.md



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/blas-ext-base-sapxsumors/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/blas/ext/base/dapxsumors]: https://github.com/stdlib-js/blas-ext-base-dapxsumors



[@stdlib/blas/ext/base/gapxsumors]: https://github.com/stdlib-js/blas-ext-base-gapxsumors



[@stdlib/blas/ext/base/sapxsum]: https://github.com/stdlib-js/blas-ext-base-sapxsum



[@stdlib/blas/ext/base/ssumors]: https://github.com/stdlib-js/blas-ext-base-ssumors