npm package: @stdlib/complex-float64-base-mul
Description: Multiply two double-precision complex floating-point numbers.
Author: The Stdlib Authors
Latest version: 0.2.1

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# mul

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> Multiply two double-precision complex floating-point numbers.

<section class="intro">

</section>

<!-- /.intro -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

```javascript
var mul = require( '@stdlib/complex-float64-base-mul' );
```

#### mul( z1, z2 )

Multiplies two double-precision complex floating-point numbers.

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

var z1 = new Complex128( 5.0, 3.0 );
var z2 = new Complex128( -2.0, 1.0 );

var v = mul( z1, z2 );
// returns <Complex128>[ -13.0, -1.0 ]
```

The function supports the following parameters:

-   **z1**: first [complex number][@stdlib/complex/float64/ctor].
-   **z2**: second [complex number][@stdlib/complex/float64/ctor].

#### mul.assign( re1, im1, re2, im2, out, strideOut, offsetOut )

Multiplies two double-precision complex floating-point numbers and assigns results to a provided output array.

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

var out = new Float64Array( 2 );
var v = mul.assign( 5.0, 3.0, -2.0, 1.0, out, 1, 0 );
// returns <Float64Array>[ -13.0, -1.0 ]

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

The function supports the following parameters:

-   **re1**: real component of the first complex number.
-   **im1**: imaginary component of the first complex number.
-   **re2**: real component of the second complex number.
-   **im2**: imaginary component of the second complex number.
-   **out**: output array.
-   **strideOut**: stride length for `out`.
-   **offsetOut**: starting index for `out`.

#### mul.strided( z1, sz1, oz1, z2, sz2, oz2, out, so, oo )

Multiplies two double-precision complex floating-point numbers stored in real-valued strided array views and assigns results to a provided strided output array.

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

var z1 = new Float64Array( [ 5.0, 3.0 ] );
var z2 = new Float64Array( [ -2.0, 1.0 ] );
var out = new Float64Array( 2 );

var v = mul.strided( z1, 1, 0, z2, 1, 0, out, 1, 0 );
// returns <Float64Array>[ -13.0, -1.0 ]

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

The function supports the following parameters:

-   **z1**: first complex number strided array view.
-   **sz1**: stride length for `z1`.
-   **oz1**: starting index for `z1`.
-   **z2**: second complex number strided array view.
-   **sz2**: stride length for `z2`.
-   **oz2**: starting index for `z2`.
-   **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 mul = require( '@stdlib/complex-float64-base-mul' );

// Generate arrays of random values:
var z1 = new Complex128Array( discreteUniform( 200, -50, 50 ) );
var z2 = new Complex128Array( discreteUniform( 200, -50, 50 ) );

// Perform element-wise multiplication:
logEachMap( '(%s) * (%s) = %s', z1, z2, mul );
```

</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/mul.h"
```

#### stdlib_base_complex128_mul( z1, z2 )

Multiplies two double-precision complex floating-point numbers.

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

stdlib_complex128_t z1 = stdlib_complex128( 5.0, 3.0 );
stdlib_complex128_t z2 = stdlib_complex128( -2.0, 1.0 );

stdlib_complex128_t out = stdlib_base_complex128_mul( z1, z2 );

double re = stdlib_complex128_real( out );
// returns -13.0

double im = stdlib_complex128_imag( out );
// returns -1.0
```

The function accepts the following arguments:

-   **z1**: `[in] stdlib_complex128_t` input value.
-   **z2**: `[in] stdlib_complex128_t` input value.

```c
stdlib_complex128_t stdlib_base_complex128_mul( const stdlib_complex128_t z1, const stdlib_complex128_t z2 );
```

</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/mul.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_mul( v, v );
        stdlib_complex128_reim( y, &re, &im );
        printf( "mul(z, z) = %lf + %lfi\n", re, im );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/complex-float64/base/add`][@stdlib/complex/float64/base/add]</span><span class="delimiter">: </span><span class="description">add two double-precision complex floating-point numbers.</span>
-   <span class="package-name">[`@stdlib/complex-float64/base/div`][@stdlib/complex/float64/base/div]</span><span class="delimiter">: </span><span class="description">divide two complex numbers.</span>
-   <span class="package-name">[`@stdlib/complex-float64/base/sub`][@stdlib/complex/float64/base/sub]</span><span class="delimiter">: </span><span class="description">subtract two double-precision complex floating-point numbers.</span>

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## 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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