npm package: @stdlib/complex-float64-base-scale
Description: Scale a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.
Author: The Stdlib Authors
Latest version: 0.1.1

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# scale

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

<section class="intro">

</section>

<!-- /.intro -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

```javascript
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.

```javascript
var Complex128 = require( '@stdlib/complex-float64-ctor' );

var z = new Complex128( 5.0, 3.0 );

var v = scale( 5.0, z );
// returns <Complex128>[ 25.0, 15.0 ]
```

The function supports the following parameters:

-   **alpha**: real-valued scalar constant.
-   **z**: [complex number][@stdlib/complex/float64/ctor].

#### 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.

```javascript
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.

```javascript
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`.

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var Complex128Array = require( '@stdlib/array-complex128' );
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var scale = require( '@stdlib/complex-float64-base-scale' );

// Generate an array of random values:
var values = new Complex128Array( discreteUniform( 200, -50, 50 ) );

// Scale each by a scalar constant:
logEachMap( '%0.1f * (%s) = %s', 5.0, values, scale );
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#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.

```c
#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.

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

</section>

<!-- /.usage -->

<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

</section>

<!-- /.notes -->

<!-- C API usage examples. -->

<section class="examples">

### Examples

```c
#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 );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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* * *

## 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

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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