https://github.com/stdlib-js/blas-base-zaxpy
Scale a double-precision complex floating-point vector by a double-precision complex floating-point constant and add the result to a double-precision complex floating-point vector.
https://github.com/stdlib-js/blas-base-zaxpy
add algebra array blas cp javascript level-1 linear math mathematics ndarray node node-js nodejs scale stdlib subroutines typed vector zaxpy
Last synced: 10 months ago
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Scale a double-precision complex floating-point vector by a double-precision complex floating-point constant and add the result to a double-precision complex floating-point vector.
- Host: GitHub
- URL: https://github.com/stdlib-js/blas-base-zaxpy
- Owner: stdlib-js
- License: apache-2.0
- Created: 2024-07-09T18:00:40.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-02-16T00:43:10.000Z (11 months ago)
- Last Synced: 2025-02-23T12:18:55.687Z (11 months ago)
- Topics: add, algebra, array, blas, cp, javascript, level-1, linear, math, mathematics, ndarray, node, node-js, nodejs, scale, stdlib, subroutines, typed, vector, zaxpy
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.62 MB
- Stars: 1
- 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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# zaxpy
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Scale a double-precision complex floating-point vector by a double-precision complex floating-point constant and add the result to a double-precision complex floating-point vector.
## Installation
```bash
npm install @stdlib/blas-base-zaxpy
```
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 zaxpy = require( '@stdlib/blas-base-zaxpy' );
```
#### zaxpy( N, za, zx, strideX, zy, strideY )
Scales values from `zx` by `za` and adds the result to `zy`.
```javascript
var Complex128Array = require( '@stdlib/array-complex128' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var zy = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var za = new Complex128( 2.0, 2.0 );
zaxpy( 3, za, zx, 1, zy, 1 );
// zy => [ -1.0, 7.0, -1.0, 15.0, -1.0, 23.0 ]
```
The function has the following parameters:
- **N**: number of indexed elements.
- **za**: scalar [`Complex128`][@stdlib/complex/float64/ctor] constant.
- **zx**: first input [`Complex128Array`][@stdlib/array/complex128].
- **strideX**: index increment for `zx`.
- **zy**: second input [`Complex128Array`][@stdlib/array/complex128].
- **strideY**: index increment for `zy`.
The `N` and stride parameters determine how values from `zx` are scaled by `za` and added to `zy`. For example, to scale every other value in `zx` by `za` and add the result to every other value of `zy`,
```javascript
var Complex128Array = require( '@stdlib/array-complex128' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var za = new Complex128( 2.0, 2.0 );
zaxpy( 2, za, zx, 2, zy, 2 );
// zy => [ -1.0, 7.0, 1.0, 1.0, -1.0, 23.0, 1.0, 1.0 ]
```
Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
```javascript
var Complex128Array = require( '@stdlib/array-complex128' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
// Initial arrays...
var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy0 = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
// Define a scalar constant:
var za = new Complex128( 2.0, 2.0 );
// Create offset views...
var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var zy1 = new Complex128Array( zy0.buffer, zy0.BYTES_PER_ELEMENT*2 ); // start at 3rd element
// Scales values of `zx0` by `za` starting from second index and add the result to `zy0` starting from third index...
zaxpy( 2, za, zx1, 1, zy1, 1 );
// zy0 => [ 1.0, 1.0, 1.0, 1.0, -1.0, 15.0, -1.0, 23.0 ]
```
#### zaxpy.ndarray( N, za, zx, strideX, offsetX, zy, strideY, offsetY )
Scales values from `zx` by `za` and adds the result to `zy` using alternative indexing semantics.
```javascript
var Complex128Array = require( '@stdlib/array-complex128' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var zy = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var za = new Complex128( 2.0, 2.0 );
zaxpy.ndarray( 3, za, zx, 1, 0, zy, 1, 0 );
// zy => [ -1.0, 7.0, -1.0, 15.0, -1.0, 23.0 ]
```
The function has the following additional parameters:
- **offsetX**: starting index for `zx`.
- **offsetY**: starting index for `zy`.
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 scale values in the first input strided array starting from the second element and add the result to the second input array starting from the second element,
```javascript
var Complex128Array = require( '@stdlib/array-complex128' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var za = new Complex128( 2.0, 2.0 );
zaxpy.ndarray( 3, za, zx, 1, 1, zy, 1, 1 );
// zy => [ 1.0, 1.0, -1.0, 15.0, -1.0, 23.0, -1.0, 31.0 ]
```
## Notes
- If `N <= 0`, both functions return `zy` unchanged.
- `zaxpy()` corresponds to the [BLAS][blas] level 1 function [`zaxpy`][zaxpy].
## Examples
```javascript
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zcopy = require( '@stdlib/blas-base-zcopy' );
var zeros = require( '@stdlib/array-zeros' );
var logEach = require( '@stdlib/console-log-each' );
var zaxpy = require( '@stdlib/blas-base-zaxpy' );
function rand() {
return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}
var zx = filledarrayBy( 10, 'complex128', rand );
var zy = filledarrayBy( 10, 'complex128', rand );
var zyc = zcopy( zy.length, zy, 1, zeros( zy.length, 'complex128' ), 1 );
var za = new Complex128( 2.0, 2.0 );
// Scale values from `zx` by `za` and add the result to `zy`:
zaxpy( zx.length, za, zx, 1, zy, 1 );
// Print the results:
logEach( '(%s)*(%s) + (%s) = %s', za, zx, zyc, zy );
```
* * *
## 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/blas-base-zaxpy.svg
[npm-url]: https://npmjs.org/package/@stdlib/blas-base-zaxpy
[test-image]: https://github.com/stdlib-js/blas-base-zaxpy/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/blas-base-zaxpy/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/blas-base-zaxpy/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/blas-base-zaxpy?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-base-zaxpy/tree/deno
[deno-readme]: https://github.com/stdlib-js/blas-base-zaxpy/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/blas-base-zaxpy/tree/umd
[umd-readme]: https://github.com/stdlib-js/blas-base-zaxpy/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/blas-base-zaxpy/tree/esm
[esm-readme]: https://github.com/stdlib-js/blas-base-zaxpy/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/blas-base-zaxpy/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/blas-base-zaxpy/main/LICENSE
[blas]: http://www.netlib.org/blas
[zaxpy]: https://www.netlib.org/lapack/explore-html/d5/d4b/group__axpy_ga0b7bac1f4d42514074a48f14f5f9caa0.html#ga0b7bac1f4d42514074a48f14f5f9caa0
[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
[@stdlib/array/complex128]: https://github.com/stdlib-js/array-complex128
[@stdlib/complex/float64/ctor]: https://github.com/stdlib-js/complex-float64-ctor