npm package: @stdlib/math-base-ops-cneg
Description: Negate a double-precision complex floating-point number.
Author: The Stdlib Authors
Latest version: 0.2.2

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# cneg

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> Negate a double-precision complex floating-point number.

<!-- 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>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/math-base-ops-cneg
```

</section>

<section class="usage">

## Usage

```javascript
var cneg = require( '@stdlib/math-base-ops-cneg' );
```

#### cneg( z )

Negates a double-precision complex floating-point number.

```javascript
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( -4.2, 5.5 );

var out = cneg( z );
// returns <Complex128>

var re = real( out );
// returns 4.2

var im = imag( out );
// returns -5.5

z = new Complex128( 0.0, 0.0 );

out = cneg( z );
// returns <Complex128>

re = real( out );
// returns -0.0

im = imag( out );
// returns -0.0

z = new Complex128( NaN, NaN );

out = cneg( z );
// returns <Complex128>

re = real( out );
// returns NaN

im = imag( out );
// returns NaN
```

</section>

<!-- /.usage -->

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

<section class="notes">

</section>

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<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var cneg = require( '@stdlib/math-base-ops-cneg' );

function randomComplex() {
    var re = discreteUniform( -50, 50 );
    var im = discreteUniform( -50, 50 );
    return new Complex128( re, im );
}

var z;
var o;
var i;

for ( i = 0; i < 100; i++ ) {
    z = randomComplex();
    o = cneg( z );
    console.log( 'negate(%s) = %s', z.toString(), o.toString() );
}
```

</section>

<!-- /.examples -->

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* * *

<section class="c">

## C APIs

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<section class="intro">

</section>

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<section class="usage">

### Usage

```c
#include "stdlib/math/base/ops/cneg.h"
```

#### stdlib_base_cneg( z )

Negates a double-precision complex floating-point number.

```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( 3.0, -2.0 );

stdlib_complex128_t out = stdlib_base_cneg( z );

double re = stdlib_complex128_real( out );
// returns -3.0

double im = stdlib_complex128_imag( out );
// returns 2.0
```

The function accepts the following arguments:

-   **z**: `[in] stdlib_complex128_t` input value.

```c
stdlib_complex128_t stdlib_base_cneg( 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/math/base/ops/cneg.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_cneg( v );
        stdlib_complex128_reim( y, &re, &im );
        printf( "cneg(z) = %lf + %lfi\n", re, im );
    }
}
```

</section>

<!-- /.examples -->

</section>

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</section>

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* * *

## See Also

-   <span class="package-name">[`@stdlib/math-base/special/cabs`][@stdlib/math/base/special/cabs]</span><span class="delimiter">: </span><span class="description">compute the absolute value of a double-precision complex floating-point number.</span>

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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; 2016-2024. The Stdlib [Authors][stdlib-authors].

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