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scale

Scale a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.

Installation

npm install @stdlib/complex-float64-base-scale

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 scale = require( '@stdlib/complex-float64-base-scale' );

scale( alpha, z )

Scales a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.

var Complex128 = require( '@stdlib/complex-float64-ctor' );
var real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );

var z = new Complex128( 5.0, 3.0 );

var v = scale( 5.0, z );
// returns <Complex128>

var re = real( v );
// returns 25.0

var im = imag( v );
// returns 15.0

The function supports the following parameters:

• alpha: real-valued scalar constant.
• z: complex number.

scale.assign( alpha, re1, im1, out, strideOut, offsetOut )

Scales a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant and assigns results to a provided output array.

var Float64Array = require( '@stdlib/array-float64' );

var out = new Float64Array( 2 );
var v = scale.assign( 5.0, 5.0, 3.0, out, 1, 0 );
// returns <Float64Array>[ 25.0, 15.0 ]

var bool = ( out === v );
// returns true

The function supports the following parameters:

• alpha: real-valued scalar constant.
• re: real component of the complex number.
• im: imaginary component of the complex number.
• out: output array.
• strideOut: stride length for out.
• offsetOut: starting index for out.

scale.strided( alpha, z, sz, oz, out, so, oo )

Scales a double-precision complex floating-point number stored in a real-valued strided array view by a real-valued double-precision floating-point scalar constant and assigns results to a provided strided output array.

var Float64Array = require( '@stdlib/array-float64' );

var z = new Float64Array( [ 5.0, 3.0 ] );
var out = new Float64Array( 2 );

var v = scale.strided( 5.0, z, 1, 0, out, 1, 0 );
// returns <Float64Array>[ 25.0, 15.0 ]

var bool = ( out === v );
// returns true

The function supports the following parameters:

• alpha: real-valued scalar constant.
• z: complex number strided array view.
• sz: stride length for z.
• oz: starting index for z.
• out: output array.
• so: stride length for out.
• oo: starting index for out.

Examples

var Complex128 = require( '@stdlib/complex-float64-ctor' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var scale = require( '@stdlib/complex-float64-base-scale' );

var rand = discreteUniform( -50, 50 );

var z1;
var z2;
var i;
for ( i = 0; i < 100; i++ ) {
    z1 = new Complex128( rand(), rand() );
    z2 = scale( 5.0, z1 );
    console.log( '(%s) * 5.0 = %s', z1.toString(), z2.toString() );
}

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C APIs

Usage

#include "stdlib/complex/float64/base/scale.h"

stdlib_base_complex128_scale( alpha, z )

Scales a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.

#include "stdlib/complex/float64/ctor.h"
#include "stdlib/complex/float64/real.h"
#include "stdlib/complex/float64/imag.h"

stdlib_complex128_t z = stdlib_complex128( 5.0, 3.0 );

stdlib_complex128_t out = stdlib_base_complex128_scale( 5.0, z );

double re = stdlib_complex128_real( out );
// returns 25.0

double im = stdlib_complex128_imag( out );
// returns 15.0

The function accepts the following arguments:

• alpha: [in] double scalar constant.
• z: [in] stdlib_complex128_t complex number.

stdlib_complex128_t stdlib_base_complex128_scale( const double alpha, const stdlib_complex128_t z );

Examples

#include "stdlib/complex/float64/base/scale.h"
#include "stdlib/complex/float64/ctor.h"
#include "stdlib/complex/float64/reim.h"
#include <stdio.h>

int main( void ) {
    const stdlib_complex128_t x[] = {
        stdlib_complex128( 3.14, 1.5 ),
        stdlib_complex128( -3.14, 1.5 ),
        stdlib_complex128( 0.0, -0.0 ),
        stdlib_complex128( 0.0/0.0, 0.0/0.0 )
    };

    stdlib_complex128_t v;
    stdlib_complex128_t y;
    double re;
    double im;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        stdlib_complex128_reim( v, &re, &im );
        printf( "z = %lf + %lfi\n", re, im );

        y = stdlib_base_complex128_scale( 5.0, v );
        stdlib_complex128_reim( y, &re, &im );
        printf( "scale(5.0, z) = %lf + %lfi\n", re, im );
    }
}

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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 © 2016-2025. The Stdlib Authors.