https://github.com/stdlib-js/blas-base-sswap
Interchange two single-precision floating-point vectors.
https://github.com/stdlib-js/blas-base-sswap
algebra array blas float32 interchange javascript level-1 linear math mathematics ndarray node node-js nodejs single sswap stdlib subroutines swap vector
Last synced: about 1 month ago
JSON representation
Interchange two single-precision floating-point vectors.
- Host: GitHub
- URL: https://github.com/stdlib-js/blas-base-sswap
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-14T16:51:43.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2026-03-02T03:46:57.000Z (2 months ago)
- Last Synced: 2026-03-25T05:59:14.330Z (about 2 months ago)
- Topics: algebra, array, blas, float32, interchange, javascript, level-1, linear, math, mathematics, ndarray, node, node-js, nodejs, single, sswap, stdlib, subroutines, swap, vector
- Language: C
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 605 KB
- Stars: 2
- 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
- Notice: NOTICE
Awesome Lists containing this project
README
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# sswap
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Interchange two single-precision floating-point vectors.
## Installation
```bash
npm install @stdlib/blas-base-sswap
```
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 sswap = require( '@stdlib/blas-base-sswap' );
```
#### sswap( N, x, strideX, y, strideY )
Interchanges vectors `x` and `y`.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
var y = new Float32Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
sswap( x.length, x, 1, y, 1 );
// x => [ 6.0, 7.0, 8.0, 9.0, 10.0 ]
// y => [ 1.0, 2.0, 3.0, 4.0, 5.0 ]
```
The function has the following parameters:
- **N**: number of indexed elements.
- **x**: first input [`Float32Array`][mdn-float32array].
- **strideX**: index increment for `x`.
- **y**: second input [`Float32Array`][mdn-float32array].
- **strideY**: index increment for `y`.
The `N` and stride parameters determine how values from the strided arrays are accessed at runtime. For example, to swap in reverse order every other value in `x` with the first `N` elements of `y`,
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Float32Array( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
sswap( 3, x, -2, y, 1 );
// x => [ 9.0, 2.0, 8.0, 4.0, 7.0, 6.0 ]
// y => [ 5.0, 3.0, 1.0, 10.0, 11.0, 12.0 ]
```
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( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y0 = new Float32Array( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
// 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
// Swap in reverse order every other value from `x1` with `y1`...
sswap( 3, x1, -2, y1, 1 );
// x0 => [ 1.0, 12.0, 3.0, 11.0, 5.0, 10.0 ]
// y0 => [ 7.0, 8.0, 9.0, 6.0, 4.0, 2.0 ]
```
#### sswap.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )
Interchanges vectors `x` and `y` using alternative indexing semantics.
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
var y = new Float32Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
sswap.ndarray( x.length, x, 1, 0, y, 1, 0 );
// x => [ 6.0, 7.0, 8.0, 9.0, 10.0 ]
// y => [ 1.0, 2.0, 3.0, 4.0, 5.0 ]
```
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, the offset parameters support indexing semantics based on starting indices. For example, to swap every other value in `x` starting from the second value with the last `N` elements in `y` where `x[i] = y[n]`, `x[i+2] = y[n-1]`,...,
```javascript
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Float32Array( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
sswap.ndarray( 3, x, 2, 1, y, -1, y.length-1 );
// x => [ 1.0, 12.0, 3.0, 11.0, 5.0, 10.0 ]
// y => [ 7.0, 8.0, 9.0, 6.0, 4.0, 2.0 ]
```
## Notes
- If `N <= 0`, both functions leave `x` and `y` unchanged.
- `sswap()` corresponds to the [BLAS][blas] level 1 function [`sswap`][sswap].
## Examples
```javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var sswap = require( '@stdlib/blas-base-sswap' );
var opts = {
'dtype': 'float32'
};
var x = discreteUniform( 10, 0, 500, opts );
console.log( x );
var y = discreteUniform( x.length, 0, 255, opts );
console.log( y );
// Swap elements in `x` and `y` starting from the end of `y`:
sswap( x.length, x, 1, y, -1 );
console.log( x );
console.log( y );
```
* * *
## C APIs
### Usage
```c
#include "stdlib/blas/base/sswap.h"
```
#### c_sswap( N, \*X, strideX, \*Y, strideY )
Interchanges two single-precision floating-point vectors.
```c
float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
float y[] = { 6.0f, 7.0f, 8.0f, 9.0f, 10.0f };
c_sswap( 5, x, 1, y, 1 );
```
The function accepts the following arguments:
- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[inout] float*` first input array.
- **strideX**: `[in] CBLAS_INT` index increment for `X`.
- **Y**: `[inout] float*` second input array.
- **strideY**: `[in] CBLAS_INT` index increment for `Y`.
```c
void c_sswap( const CBLAS_INT N, float *X, const CBLAS_INT strideX, float *Y, const CBLAS_INT strideY );
```
#### c_sswap_ndarray( N, \*X, strideX, offsetX, \*Y, strideY, offsetY )
Interchanges two single-precision floating-point vectors using alternative indexing semantics.
```c
float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
float y[] = { 6.0f, 7.0f, 8.0f, 9.0f, 10.0f };
c_sswap_ndarray( 3, x, 1, 2, y, 1, 2 );
```
The function accepts the following arguments:
- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[inout] float*` first input array.
- **strideX**: `[in] CBLAS_INT` index increment for `X`.
- **offsetX**: `[in] CBLAS_INT` starting index for `X`.
- **Y**: `[inout] float*` second input array.
- **strideY**: `[in] CBLAS_INT` index increment for `Y`.
- **offsetY**: `[in] CBLAS_INT` starting index for `Y`.
```c
void c_sswap_ndarray( const CBLAS_INT N, float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, float *Y, const CBLAS_INT strideY, const CBLAS_INT offsetY );
```
### Examples
```c
#include "stdlib/blas/base/sswap.h"
#include
int main( void ) {
// Create strided arrays:
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 indexed elements:
const int N = 4;
// Specify stride lengths:
const int strideX = 2;
const int strideY = -2;
// Interchange elements:
c_sswap( N, x, strideX, y, strideY );
// Print the result:
for ( int i = 0; i < 8; i++ ) {
printf( "x[ %i ] = %f\n", i, x[ i ] );
printf( "y[ %i ] = %f\n", i, y[ i ] );
}
// Interchange elements:
c_sswap_ndarray( N, x, strideX, 0, y, strideY, 6 );
// Print the result:
for ( int i = 0; i < 8; i++ ) {
printf( "x[ %i ] = %f\n", i, x[ i ] );
printf( "y[ %i ] = %f\n", i, y[ i ] );
}
}
```
* * *
## See Also
- [`@stdlib/blas-base/dswap`][@stdlib/blas/base/dswap]: interchange two double-precision floating-point vectors.
- [`@stdlib/blas-base/gswap`][@stdlib/blas/base/gswap]: interchange two vectors.
- [`@stdlib/blas-base/scopy`][@stdlib/blas/base/scopy]: copy values from x into y.
- [`@stdlib/blas-sswap`][@stdlib/blas/sswap]: interchange two single-precision floating-point vectors.
* * *
## 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 © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/blas-base-sswap.svg
[npm-url]: https://npmjs.org/package/@stdlib/blas-base-sswap
[test-image]: https://github.com/stdlib-js/blas-base-sswap/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/blas-base-sswap/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/blas-base-sswap/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/blas-base-sswap?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[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-base-sswap/tree/deno
[deno-readme]: https://github.com/stdlib-js/blas-base-sswap/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/blas-base-sswap/tree/umd
[umd-readme]: https://github.com/stdlib-js/blas-base-sswap/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/blas-base-sswap/tree/esm
[esm-readme]: https://github.com/stdlib-js/blas-base-sswap/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/blas-base-sswap/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/blas-base-sswap/main/LICENSE
[blas]: http://www.netlib.org/blas
[sswap]: http://www.netlib.org/lapack/explore-html/df/d28/group__single__blas__level1.html
[mdn-float32array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array
[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
[@stdlib/blas/base/dswap]: https://github.com/stdlib-js/blas-base-dswap
[@stdlib/blas/base/gswap]: https://github.com/stdlib-js/blas-base-gswap
[@stdlib/blas/base/scopy]: https://github.com/stdlib-js/blas-base-scopy
[@stdlib/blas/sswap]: https://github.com/stdlib-js/blas-sswap