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cfill

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

Installation

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 available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md 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

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.

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 <Complex64>

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.
• 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:

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 <Complex64>

var re = realf( y );
// returns 10.0

var im = imagf( y );
// returns 10.0

y = x.get( 1 );
// returns <Complex64>

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 views.

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 <Complex64>

var re = realf( y );
// returns 1.0

var im = imagf( y );
// returns 2.0

y = x0.get( 1 );
// returns <Complex64>

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.

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 <Complex64>

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 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:

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 <Complex64>

var re = realf( y );
// returns 1.0

var im = imagf( y );
// returns 2.0

y = x.get( 1 );
// returns <Complex64>

re = realf( y );
// returns 10.0

im = imagf( y );
// returns 10.0

y = x.get( 2 );
// returns <Complex64>

re = realf( y );
// returns 10.0

im = imagf( y );
// returns 10.0

Notes

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

Examples

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

#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.

#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.

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.

#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.

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

#include "stdlib/blas/ext/base/cfill.h"
#include "stdlib/complex/float32/ctor.h"
#include <stdio.h>

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 ] );
    }
}

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Notice

This package is part of 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, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.