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# Complex128Vector

> Create a double-precision complex floating-point vector (i.e., a one-dimensional [ndarray][@stdlib/ndarray/ctor]).

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## Usage

```javascript
var Complex128Vector = require( '@stdlib/ndarray/vector/complex128' );
```

#### Complex128Vector( \[options] )

Returns a one-dimensional double-precision complex floating-point [ndarray][@stdlib/ndarray/ctor].

```javascript
var numel = require( '@stdlib/ndarray/numel' );

var arr = new Complex128Vector();
// returns <ndarray>

var len = numel( arr );
// returns 0
```

The function accepts the following options:

-   **order**: specifies whether an [ndarray][@stdlib/ndarray/ctor] is `'row-major'` (C-style) or `'column-major'` (Fortran-style). Default: `'row-major'`.
-   **mode**: specifies how to handle indices which exceed array dimensions (see [`ndarray`][@stdlib/ndarray/ctor]). Default: `'throw'`.
-   **readonly**: boolean indicating whether an array should be **read-only**. Default: `false`.

#### Complex128Vector( length\[, options] )

Returns a one-dimensional double-precision complex floating-point [ndarray][@stdlib/ndarray/ctor] having a specified `length`.

```javascript
var numel = require( '@stdlib/ndarray/numel' );

var arr = new Complex128Vector( 5 );
// returns <ndarray>

var len1 = numel( arr );
// returns 5
```

#### Complex128Vector( obj\[, options] )

Creates a one-dimensional double-precision complex floating-point [ndarray][@stdlib/ndarray/ctor] from an array-like object or iterable.

```javascript
var numel = require( '@stdlib/ndarray/numel' );

var arr = new Complex128Vector( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
// returns <ndarray>

var len1 = numel( arr );
// returns 3
```

#### Complex128Vector( buffer\[, byteOffset\[, length]]\[, options] )

Returns a one-dimensional double-precision complex floating-point [ndarray][@stdlib/ndarray/ctor] view of an [`ArrayBuffer`][@stdlib/array/buffer].

```javascript
var ArrayBuffer = require( '@stdlib/array/buffer' );
var numel = require( '@stdlib/ndarray/numel' );

var buf = new ArrayBuffer( 64 );

var arr1 = new Complex128Vector( buf );
// returns <ndarray>

var len1 = numel( arr1 );
// returns 4

var arr2 = new Complex128Vector( buf, 16 );
// returns <ndarray>

var len2 = numel( arr2 );
// returns 3

var arr3 = new Complex128Vector( buf, 16, 1 );
// returns <ndarray>

var len3 = numel( arr3 );
// returns 1
```

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## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var sum = require( '@stdlib/blas/ext/sum' );
var map = require( '@stdlib/ndarray/map' );
var real = require( '@stdlib/complex/float64/real' );
var imag = require( '@stdlib/complex/float64/imag' );
var Complex128 = require( '@stdlib/complex/float64/ctor' );
var Complex128Vector = require( '@stdlib/ndarray/vector/complex128' );

// Create a vector containing random values:
var x = new Complex128Vector( discreteUniform( 20, 0, 100 ) );

// Compute the sum:
var v = sum( x );
console.log( v.get() );

// Define a function which applies a threshold to real and imaginary components:
function threshold( v ) {
    if ( real( v ) > 10 && imag( v ) > 10 ) {
        return v;
    }
    return new Complex128( 0.0, 0.0 );
}

// Apply threshold:
var y = map( x, threshold );

// Recompute the sum:
v = sum( y );
console.log( v.get() );
```

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</section>

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[@stdlib/array/buffer]: https://www.npmjs.com/package/@stdlib/array-buffer

[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray/tree/main/ctor

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