npm package: @stdlib/complex-float64-base-neg
Description: Negate a double-precision complex floating-point number.
Author: The Stdlib Authors
Latest version: 0.1.1

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# cneg

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

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

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

#### cneg( z )

Negates a double-precision complex floating-point number.

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

var z = new Complex128( -4.2, 5.5 );

var out = cneg( z );
// returns <Complex128>[ 4.2, -5.5 ]

z = new Complex128( 0.0, 0.0 );

out = cneg( z );
// returns <Complex128>[ -0.0, -0.0 ]

z = new Complex128( NaN, NaN );

out = cneg( z );
// returns <Complex128>[ NaN, NaN ]
```

</section>

<!-- /.usage -->

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<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/complex-float64-base-neg' );

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>

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<section class="usage">

### Usage

```c
#include "stdlib/complex/float64/base/neg.h"
```

#### stdlib_base_complex128_neg( 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_complex128_neg( 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_complex128_neg( const stdlib_complex128_t z );
```

</section>

<!-- /.usage -->

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<section class="notes">

</section>

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

<section class="examples">

### Examples

```c
#include "stdlib/complex/float64/base/neg.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_neg( v );
        stdlib_complex128_reim( y, &re, &im );
        printf( "cneg(z) = %lf + %lfi\n", re, im );
    }
}
```

</section>

<!-- /.examples -->

</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

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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].

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## License

See [LICENSE][stdlib-license].


## Copyright

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

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