npm package: @stdlib/complex-float64-conj
Description: Return the complex conjugate of a double-precision complex floating-point number.
Author: The Stdlib Authors
Latest version: 0.2.1

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# conj

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> Return the [complex conjugate][complex-conjugate] of 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-conj
```

</section>

<section class="usage">

## Usage

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

#### conj( z )

Returns the [complex conjugate][complex-conjugate] of a double-precision complex floating-point number.

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

var z = new Complex128( 5.0, 3.0 );

var v = conj( z );
// returns <Complex128>[ 5.0, -3.0 ]
```

</section>

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<section class="notes">

</section>

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<section class="examples">

## Examples

<!-- eslint-disable max-len -->

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

```javascript
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var conj = require( '@stdlib/complex-float64-conj' );

function random() {
    return new Complex128( discreteUniform( -10, 10 ), discreteUniform( -10, 10 ) );
}

// Generate an array of random complex numbers:
var x = filledarrayBy( 100, 'complex128', random );
// returns <Complex128Array>

// Compute the complex conjugate of each complex number...
var z;
var i;
for ( i = 0; i < x.length; i++ ) {
    z = x.get( i );
    console.log( 'conj(%s) = %s', z.toString(), conj( z ).toString() );
}
```

</section>

<!-- /.examples -->

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* * *

<section class="c">

## C APIs

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</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#include "stdlib/complex/float64/conj.h"
```

#### stdlib_complex128_conj( z )

Returns the [complex conjugate][complex-conjugate] of 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( 5.0, 2.0 );

// ...

stdlib_complex128_t v = stdlib_complex128_conj( z );

double re = stdlib_complex128_real( v );
// returns 5.0

double im = stdlib_complex128_imag( v );
// returns -2.0
```

The function accepts the following arguments:

-   **z**: `[in] stdlib_complex128_t` double-precision complex floating-point number.

```c
stdlib_complex128_t stdlib_complex128_conj( const stdlib_complex128_t z );
```

</section>

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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/conj.h"
#include "stdlib/complex/float64/real.h"
#include "stdlib/complex/float64/imag.h"
#include "stdlib/complex/float64/ctor.h"
#include <stdio.h>

int main( void ) {
    const stdlib_complex128_t x[] = {
        stdlib_complex128( 5.0, 2.0 ),
        stdlib_complex128( -2.0, 1.0 ),
        stdlib_complex128( 0.0, -0.0 ),
        stdlib_complex128( 0.0/0.0, 0.0/0.0 )
    };

    stdlib_complex128_t z;
    stdlib_complex128_t v;
    int i;
    for ( i = 0; i < 4; i++ ) {
        z = x[ i ];
        v = stdlib_complex128_conj( z );
        printf( "conj(%lf + %lfi) = %lf + %lfi\n", stdlib_complex128_real( z ), stdlib_complex128_imag( z ), stdlib_complex128_real( v ), stdlib_complex128_imag( v ) );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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</section>

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* * *

## See Also

-   <span class="package-name">[`@stdlib/complex-float64/imag`][@stdlib/complex/float64/imag]</span><span class="delimiter">: </span><span class="description">return the imaginary component of a double-precision complex floating-point number.</span>
-   <span class="package-name">[`@stdlib/complex-float64/real`][@stdlib/complex/float64/real]</span><span class="delimiter">: </span><span class="description">return the real component of a double-precision complex floating-point number.</span>
-   <span class="package-name">[`@stdlib/complex-float64/reim`][@stdlib/complex/float64/reim]</span><span class="delimiter">: </span><span class="description">return the real and imaginary components of a double-precision complex floating-point number.</span>

</section>

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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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[complex-conjugate]: https://en.wikipedia.org/wiki/Complex_conjugate

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