time-to-botec/squiggle/node_modules/@stdlib/math/base/ops/cmul/README.md

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@license Apache-2.0
Copyright (c) 2018 The Stdlib Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
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# multiply
> Multiply two complex numbers.
<section class="intro">
</section>
<!-- /.intro -->
<section class="usage">
## Usage
```javascript
var cmul = require( '@stdlib/math/base/ops/cmul' );
```
#### cmul( \[out,] re1, im1, re2, im2 )
Multiplies two `complex` numbers where each `complex` number is comprised of a **real** component `re` and an **imaginary** component `im`.
```javascript
var v = cmul( 5.0, 3.0, -2.0, 1.0 );
// returns [ -13.0, -1.0 ]
```
By default, the function returns real and imaginary components as a two-element `array`. To avoid unnecessary memory allocation, the function supports providing an output (destination) object.
```javascript
var Float64Array = require( '@stdlib/array/float64' );
var out = new Float64Array( 2 );
var v = cmul( out, 5.0, 3.0, -2.0, 1.0 );
// returns <Float64Array>[ -13.0, -1.0 ]
var bool = ( v === out );
// returns true
```
</section>
<!-- /.usage -->
<section class="examples">
## Examples
<!-- eslint no-undef: "error" -->
```javascript
var Complex128 = require( '@stdlib/complex/float64' );
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );
var cmul = require( '@stdlib/math/base/ops/cmul' );
var re;
var im;
var z1;
var z2;
var z3;
var o;
var i;
for ( i = 0; i < 100; i++ ) {
re = round( randu()*100.0 ) - 50.0;
im = round( randu()*100.0 ) - 50.0;
z1 = new Complex128( re, im );
re = round( randu()*100.0 ) - 50.0;
im = round( randu()*100.0 ) - 50.0;
z2 = new Complex128( re, im );
o = cmul( real(z1), imag(z1), real(z2), imag(z2) );
z3 = new Complex128( o[ 0 ], o[ 1 ] );
console.log( '(%s) * (%s) = %s', z1.toString(), z2.toString(), z3.toString() );
}
```
</section>
<!-- /.examples -->
<section class="links">
</section>
<!-- /.links -->