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

Fill a single-precision complex floating-point strided array with a specified scalar constant.
https://github.com/stdlib-js/blas-ext-base-cfill

array assign blas broadcast complex64 complex64array constant copy equal extended fill javascript math mathematics node node-js nodejs set stdlib strided

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Fill a single-precision complex floating-point strided array with a specified scalar constant.

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README 

        



  

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# cfill



[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] 



> Fill a single-precision complex floating-point strided array with a specified scalar constant.



## Installation



```bash

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

```



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

```



#### cfill( N, alpha, x, strideX )



Fills a single-precision complex floating-point strided array `x` with a specified scalar constant `alpha`.



```javascript

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

var Complex64Array = require( '@stdlib/array-complex64' );

var Complex64 = require( '@stdlib/complex-float32-ctor' );

var realf = require( '@stdlib/complex-float32-real' );

var imagf = require( '@stdlib/complex-float32-imag' );



var arr = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );

var x = new Complex64Array( arr );



var alpha = new Complex64( 10.0, 10.0 );



cfill( x.length, alpha, x, 1 );



var y = x.get( 0 );

// returns 



var re = realf( y );

// returns 10.0



var im = imagf( y );

// returns 10.0

```



The function has the following parameters:



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

-   **alpha**: scalar constant.

-   **x**: input [`Complex64Array`][@stdlib/array/complex64].

-   **strideX**: stride length.



The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to fill every other element:



```javascript

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

var Complex64Array = require( '@stdlib/array-complex64' );

var Complex64 = require( '@stdlib/complex-float32-ctor' );

var realf = require( '@stdlib/complex-float32-real' );

var imagf = require( '@stdlib/complex-float32-imag' );



var arr = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );

var x = new Complex64Array( arr );



var alpha = new Complex64( 10.0, 10.0 );



cfill( 2, alpha, x, 2 );



var y = x.get( 0 );

// returns 



var re = realf( y );

// returns 10.0



var im = imagf( y );

// returns 10.0



y = x.get( 1 );

// returns 



re = realf( y );

// returns 3.0



im = imagf( y );

// returns 4.0

```



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 Complex64Array = require( '@stdlib/array-complex64' );

var Complex64 = require( '@stdlib/complex-float32-ctor' );

var realf = require( '@stdlib/complex-float32-real' );

var imagf = require( '@stdlib/complex-float32-imag' );



// Create the underlying floating-point array:

var arr = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );



// Initial array:

var x0 = new Complex64Array( arr );



// Create an offset view:

var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element



// Define a scalar constant:

var alpha = new Complex64( 10.0, 10.0 );



// Fill every other element:

cfill( 2, alpha, x1, 2 );



var y = x0.get( 0 );

// returns 



var re = realf( y );

// returns 1.0



var im = imagf( y );

// returns 2.0



y = x0.get( 1 );

// returns 



re = realf( y );

// returns 10.0



im = imagf( y );

// returns 10.0

```



#### cfill.ndarray( N, alpha, x, strideX, offsetX )



Fills a single-precision complex floating-point strided array `x` with a specified scalar constant `alpha` using alternative indexing semantics.



```javascript

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

var Complex64Array = require( '@stdlib/array-complex64' );

var Complex64 = require( '@stdlib/complex-float32-ctor' );

var realf = require( '@stdlib/complex-float32-real' );

var imagf = require( '@stdlib/complex-float32-imag' );



var arr = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );

var x = new Complex64Array( arr );



var alpha = new Complex64( 10.0, 10.0 );



cfill.ndarray( x.length, alpha, x, 1, 0 );



var y = x.get( 0 );

// returns 



var re = realf( y );

// returns 10.0



var im = imagf( y );

// returns 10.0

```



The function has the following additional parameters:



-   **offsetX**: starting index.



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 only the last two elements of the strided array:



```javascript

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

var Complex64Array = require( '@stdlib/array-complex64' );

var Complex64 = require( '@stdlib/complex-float32-ctor' );

var realf = require( '@stdlib/complex-float32-real' );

var imagf = require( '@stdlib/complex-float32-imag' );



var arr = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );

var x = new Complex64Array( arr );



var alpha = new Complex64( 10.0, 10.0 );



cfill.ndarray( 2, alpha, x, 1, x.length-2 );



var y = x.get( 0 );

// returns 



var re = realf( y );

// returns 1.0



var im = imagf( y );

// returns 2.0



y = x.get( 1 );

// returns 



re = realf( y );

// returns 10.0



im = imagf( y );

// returns 10.0



y = x.get( 2 );

// returns 



re = realf( y );

// returns 10.0



im = imagf( y );

// returns 10.0

```



## Notes



-   If `N <= 0`, both functions return the strided array unchanged.



## Examples



```javascript

var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );

var Complex64Array = require( '@stdlib/array-complex64' );

var Complex64 = require( '@stdlib/complex-float32-ctor' );

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



var xbuf = discreteUniform( 20, -100, 100, {

    'dtype': 'float32'

});

var x = new Complex64Array( xbuf.buffer );

var alpha = new Complex64( 10.0, 10.0 );



cfill( x.length, alpha, x, 1 );

console.log( x.get( 0 ).toString() );

```



### Usage



```c

#include "stdlib/blas/ext/base/cfill.h"

```



#### stdlib_strided_cfill( N, alpha, \*X, strideX )



Fills a single-precision complex floating-point strided array `X` with a specified scalar constant `alpha`.



```c

#include "stdlib/complex/float32/ctor.h"



float x[] = { 1.0f, 2.0f, 3.0f, 4.0f };

const stdlib_complex64_t alpha = stdlib_complex64( 2.0f, 2.0f );



stdlib_strided_cfill( 2, alpha, (stdlib_complex64_t *)x, 1 );

```



The function accepts the following arguments:



-   **N**: `[in] CBLAS_INT` number of indexed elements.

-   **alpha**: `[in] stdlib_complex64_t` scalar constant.

-   **X**: `[out] stdlib_complex64_t*` input array.

-   **strideX**: `[in] CBLAS_INT` stride length for `X`.



```c

void stdlib_strided_cfill( const CBLAS_INT N, const stdlib_complex64_t alpha, stdlib_complex64_t *X, const CBLAS_INT strideX );

```



#### stdlib_strided_cfill_ndarray( N, alpha, \*X, strideX, offsetX )



Fills a single-precision complex floating-point strided array `X` with a specified scalar constant `alpha` using alternative indexing semantics.



```c

#include "stdlib/complex/float32/ctor.h"



float x[] = { 1.0f, 2.0f, 3.0f, 4.0f };

const stdlib_complex64_t alpha = stdlib_complex64( 2.0f, 2.0f );



stdlib_strided_cfill_ndarray( 4, alpha, (stdlib_complex64_t *x), 1, 0 );

```



The function accepts the following arguments:



-   **N**: `[in] CBLAS_INT` number of indexed elements.

-   **alpha**: `[in] stdlib_complex64_t` scalar constant.

-   **X**: `[out] stdlib_complex64_t*` input array.

-   **strideX**: `[in] CBLAS_INT` stride length for `X`.

-   **offsetX**: `[in] CBLAS_INT` starting index for `X`.



```c

void stdlib_strided_cfill_ndarray( const CBLAS_INT N, const stdlib_complex64_t alpha, stdlib_complex64_t *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );

```



### Examples



```c

#include "stdlib/blas/ext/base/cfill.h"

#include "stdlib/complex/float32/ctor.h"

#include 



int main( void ) {

    // Create a strided array of interleaved real and imaginary components:

    float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };



    // Create a complex scalar:

    const stdlib_complex64_t alpha = stdlib_complex64( 2.0f, 2.0f );



    // Specify the number of indexed elements:

    const int N = 4;



    // Specify a stride:

    const int strideX = 1;



    // Fill the array:

    stdlib_strided_cfill( N, alpha, (stdlib_complex64_t *)x, strideX );



    // Print the result:

    for ( int i = 0; i < N; i++ ) {

        printf( "x[ %i ] = %f + %fj\n", i, x[ i*2 ], x[ (i*2)+1 ] );

    }

}

```



* * *



## 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-cfill.svg

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



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

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



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

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

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

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

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

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

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

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



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/blas-ext-base-cfill/main/LICENSE



[@stdlib/array/complex64]: https://github.com/stdlib-js/array-complex64



[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray