@stdlib/array-complex128

Complex128Array.

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README

Complex128Array

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128-bit complex number array.

Installation

npm install @stdlib/array-complex128

Usage

var Complex128Array = require( '@stdlib/array-complex128' );

Complex128Array()

Creates a 128-bit complex number array.

var arr = new Complex128Array();
// returns <Complex128Array>

Complex128Array( length )

Creates a 128-bit complex number array having a specified length.

var arr = new Complex128Array( 10 );
// returns <Complex128Array>

var len = arr.length;
// returns 10

Complex128Array( complexarray )

Creates a 128-bit complex number array from another complex number array.

var arr1 = new Complex128Array( [ 1.0, -1.0, 2.0, -2.0 ] ); // [ re, im, re, im ]
// returns <Complex128Array>

var arr2 = new Complex128Array( arr1 );
// returns <Complex128Array>

var len = arr2.length;
// returns 2

Complex128Array( typedarray )

Creates a 128-bit complex number array from a typed array containing interleaved real and imaginary components.

var Float64Array = require( '@stdlib/array-float64' );

var buf = new Float64Array( [ 1.0, -1.0, 2.0, -2.0 ] ); // [ re, im, re, im ]
// returns <Float64Array>[ 1.0, -1.0, 2.0, -2.0 ]

var arr = new Complex128Array( buf );
// returns <Complex128Array>

var len = arr.length;
// returns 2

Complex128Array( obj )

Creates a 128-bit complex number array from an array-like object or iterable.

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

// From an array of interleaved real and imaginary components:
var arr1 = new Complex128Array( [ 1.0, -1.0, 2.0, -2.0 ] );
// returns <Complex128Array>

var len = arr1.length;
// returns 2

// From an array containing complex numbers:
var buf = [ new Complex128( 1.0, -1.0 ), new Complex128( 2.0, -2.0 ) ];
var arr2 = new Complex128Array( buf );

len = arr2.length;
// returns 2

Complex128Array( buffer[, byteOffset[, length]] )

Returns a 128-bit complex number array view of an ArrayBuffer.

var ArrayBuffer = require( '@stdlib/array-buffer' );
var buf = new ArrayBuffer( 480 );

var arr1 = new Complex128Array( buf );
// returns <Complex128Array>

var len = arr1.length;
// returns 30

var arr2 = new Complex128Array( buf, 16 );
// returns <Complex128Array>

len = arr2.length;
// returns 29

var arr3 = new Complex128Array( buf, 16, 20 );
// returns <Complex128Array>

len = arr3.length;
// returns 20

Properties

Complex128Array.BYTES_PER_ELEMENT

Static property returning the size (in bytes) of each array element.

var nbytes = Complex128Array.BYTES_PER_ELEMENT;
// returns 16

Complex128Array.name

Static property returning the constructor name.

var str = Complex128Array.name;
// returns 'Complex128Array'

Complex128Array.prototype.buffer

Pointer to the underlying data buffer.

var arr = new Complex128Array( 2 );
// returns <Complex128Array>

var buf = arr.buffer;
// returns <ArrayBuffer>

Complex128Array.prototype.byteLength

Size (in bytes) of the array.

var arr = new Complex128Array( 10 );
// returns <Complex128Array>

var nbytes = arr.byteLength;
// returns 160

Complex128Array.prototype.byteOffset

Offset (in bytes) of the array from the start of its underlying ArrayBuffer.

var ArrayBuffer = require( '@stdlib/array-buffer' );

var arr = new Complex128Array( 10 );
// returns <Complex128Array>

var offset = arr.byteOffset;
// returns 0

var buf = new ArrayBuffer( 480 );
arr = new Complex128Array( buf, 128 );
// returns <Complex128Array>

offset = arr.byteOffset;
// returns 128

Complex128Array.prototype.BYTES_PER_ELEMENT

Size (in bytes) of each array element.

var arr = new Complex128Array( 10 );
// returns <Complex128Array>

var nbytes = arr.BYTES_PER_ELEMENT;
// returns 16

Complex128Array.prototype.length

Number of array elements.

var arr = new Complex128Array( 10 );
// returns <Complex128Array>

var len = arr.length;
// returns 10

Methods

Complex128Array.from( src[, clbk[, thisArg]] )

Creates a new 128-bit complex number array from an array-like object or an iterable.

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

// Create an array from interleaved real and imaginary components:
var arr = Complex128Array.from( [ 1.0, -1.0 ] );
// returns <Complex128Array>

var len = arr.length;
// returns 1

// Create an array from an array of complex numbers:
arr = Complex128Array.from( [ new Complex128( 1.0, -1.0 ) ] );
// returns <Complex128Array>

len = arr.length;
// returns 1

The iterator returned by an iterable must return either a complex number or an array-like object containing a real and imaginary component.

var ITERATOR_SYMBOL = require( '@stdlib/symbol-iterator' );
var Float64Array = require( '@stdlib/array-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var iter;
var arr;
var len;
var re;
var im;
var z;

// Define a function which returns an iterator protocol-compliant object...
function iterable() {
    var buf = new Float64Array( 2 );
    var i = 0;
    return {
        'next': next
    };

    function next() {
        i += 1;
        if ( i < 3 ) {
            // Reuse allocated memory...
            buf[ 0 ] = i;
            buf[ 1 ] = -i;
            return {
                'value': buf
            };
        }
        return {
            'done': true
        };
    }
}

if ( ITERATOR_SYMBOL === null ) {
    console.error( 'Environment does not support iterables.' );
} else {
    // Create an iterable:
    iter = {};
    iter[ ITERATOR_SYMBOL ] = iterable;

    // Generate a complex number array:
    arr = Complex128Array.from( iter );
    // returns <Complex128Array>

    len = arr.length;
    // returns 2

    z = arr.get( 0 );
    // returns <Complex128>

    re = real( z );
    // returns 1.0

    im = imag( z );
    // returns -1.0
}

To invoke a function for each src value, provide a callback function. If src is an iterable or an array-like object containing complex numbers, the callback must return either a complex number

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

function map( z ) {
    return new Complex128( real(z)*2.0, imag(z)*2.0 );
}

// Create a source array:
var src = [ new Complex128( 1.0, -1.0 ) ];

// Create a new complex number array by scaling the source array:
var arr = Complex128Array.from( src, map );
// returns <Complex128Array>

var len = arr.length;
// returns 1

var z = arr.get( 0 );
// returns <Complex128>

var re = real( z );
// returns 2.0

var im = imag( z );
// returns -2.0

or an array-like object containing real and imaginary components

var Float64Array = require( '@stdlib/array-float64' );
var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

// Return a callback which reuses allocated memory...
function mapFcn() {
    var buf = new Float64Array( 2 );
    return map;

    function map( z ) {
        buf[ 0 ] = real( z ) * 2.0;
        buf[ 1 ] = imag( z ) * 2.0;
        return buf;
    }
}

// Create a source array:
var src = [ new Complex128( 1.0, -1.0 ), new Complex128( 2.0, -2.0 ) ];

// Create a new complex number array by scaling the source array:
var arr = Complex128Array.from( src, mapFcn() );
// returns <Complex128Array>

var len = arr.length;
// returns 2

var z = arr.get( 0 );
// returns <Complex128>

var re = real( z );
// returns 2.0

var im = imag( z );
// returns -2.0

z = arr.get( 1 );
// returns <Complex128>

re = real( z );
// returns 4.0

im = imag( z );
// returns -4.0

If src is an array-like object containing interleaved real and imaginary components, the callback is invoked for each component and should return the transformed component value.

var Float64Array = require( '@stdlib/array-float64' );
var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

function map( v ) {
    return v * 2.0;
}

// Create a source array:
var src = new Float64Array( [ 1.0, -1.0 ] );

// Create a new complex number array by scaling the source array:
var arr = Complex128Array.from( src, map );
// returns <Complex128Array>

var len = arr.length;
// returns 1

var z = arr.get( 0 );
// returns <Complex128>

var re = real( z );
// returns 2.0

var im = imag( z );
// returns -2.0

A callback function is provided two arguments:

  • value: source value.
  • index: source index.

To set the callback execution context, provide a thisArg.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

function map( z ) {
    this.count += 1;
    return new Complex128( real(z)*2.0, imag(z)*2.0 );
}

// Create a source array:
var src = [ new Complex128( 1.0, -1.0 ), new Complex128( 1.0, -1.0 ) ];

// Define an execution context:
var ctx = {
    'count': 0
};

// Create a new complex number array by scaling the source array:
var arr = Complex128Array.from( src, map, ctx );
// returns <Complex128Array>

var len = arr.length;
// returns 2

var n = ctx.count;
// returns 2

Complex128Array.of( element0[, element1[, ...elementN]] )

Creates a new 128-bit complex number array from a variable number of arguments.

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

var arr = Complex128Array.of( 1.0, -1.0, 2.0, -2.0 );
// returns <Complex128Array>

var len = arr.length;
// returns 2

var z1 = new Complex128( 1.0, -1.0 );
var z2 = new Complex128( 2.0, -2.0 );

arr = Complex128Array.of( z1, z2 );
// returns <Complex128Array>

len = arr.length;
// returns 2

Complex128Array.prototype.copyWithin( target, start[, end] )

Copies a sequence of elements within the array starting at start and ending at end (non-inclusive) to the position starting at target.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 4 );

// Set the array elements:
arr.set( new Complex128( 1.0, -1.0 ), 0 );
arr.set( new Complex128( 2.0, -2.0 ), 1 );
arr.set( new Complex128( 3.0, -3.0 ), 2 );
arr.set( new Complex128( 4.0, -4.0 ), 3 );

// Get the first array element:
var z = arr.get( 0 );
// returns <Complex128>

var re = real( z );
// returns 1.0

var im = imag( z );
// returns -1.0

// Get the second array element:
z = arr.get( 1 );
// returns <Complex128>

re = real( z );
// returns 2.0

im = imag( z );
// returns -2.0

// Copy the last two elements to the first two elements:
arr.copyWithin( 0, 2 );

// Get the first array element:
z = arr.get( 0 );
// returns <Complex128>

re = real( z );
// returns 3.0

im = imag( z );
// returns -3.0

// Get the second array element:
z = arr.get( 1 );
// returns <Complex128>

re = real( z );
// returns 4.0

im = imag( z );
// returns -4.0

By default, end equals the number of array elements (i.e., one more than the last array index). To limit the sequence length, provide an end argument.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 4 );

// Set the array elements:
arr.set( new Complex128( 1.0, -1.0 ), 0 );
arr.set( new Complex128( 2.0, -2.0 ), 1 );
arr.set( new Complex128( 3.0, -3.0 ), 2 );
arr.set( new Complex128( 4.0, -4.0 ), 3 );

// Get the third array element:
var z = arr.get( 2 );
// returns <Complex128>

var re = real( z );
// returns 3.0

var im = imag( z );
// returns -3.0

// Get the last array element:
z = arr.get( 3 );
// returns <Complex128>

re = real( z );
// returns 4.0

im = imag( z );
// returns -4.0

// Copy the first two elements to the last two elements:
arr.copyWithin( 2, 0, 2 );

// Get the third array element:
z = arr.get( 2 );
// returns <Complex128>

re = real( z );
// returns 1.0

im = imag( z );
// returns -1.0

// Get the last array element:
z = arr.get( 3 );
// returns <Complex128>

re = real( z );
// returns 2.0

im = imag( z );
// returns -2.0

When a target, start, and/or end index is negative, the respective index is determined relative to the last array element. The following example achieves the same behavior as the previous example:

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 4 );

// Set the array elements:
arr.set( new Complex128( 1.0, -1.0 ), 0 );
arr.set( new Complex128( 2.0, -2.0 ), 1 );
arr.set( new Complex128( 3.0, -3.0 ), 2 );
arr.set( new Complex128( 4.0, -4.0 ), 3 );

// Get the third array element:
var z = arr.get( 2 );
// returns <Complex128>

var re = real( z );
// returns 3.0

var im = imag( z );
// returns -3.0

// Get the last array element:
z = arr.get( 3 );
// returns <Complex128>

re = real( z );
// returns 4.0

im = imag( z );
// returns -4.0

// Copy the first two elements to the last two elements using negative indices:
arr.copyWithin( -2, -4, -2 );

// Get the third array element:
z = arr.get( 2 );
// returns <Complex128>

re = real( z );
// returns 1.0

im = imag( z );
// returns -1.0

// Get the last array element:
z = arr.get( 3 );
// returns <Complex128>

re = real( z );
// returns 2.0

im = imag( z );
// returns -2.0

Complex128Array.prototype.entries()

Returns an iterator for iterating over array key-value pairs.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = [
    new Complex128( 1.0, -1.0 ),
    new Complex128( 2.0, -2.0 ),
    new Complex128( 3.0, -3.0 )
];
arr = new Complex128Array( arr );

// Create an iterator:
var it = arr.entries();

// Iterate over the key-value pairs...
var v = it.next().value;
// returns [ 0, <Complex128> ]

var re = real( v[ 1 ] );
// returns 1.0

var im = imag( v[ 1 ] );
// returns -1.0

v = it.next().value;
// returns [ 1, <Complex128> ]

re = real( v[ 1 ] );
// returns 2.0

im = imag( v[ 1 ] );
// returns -2.0

v = it.next().value;
// returns [ 2, <Complex128> ]

re = real( v[ 1 ] );
// returns 3.0

im = imag( v[ 1 ] );
// returns -3.0

var bool = it.next().done;
// returns true

Complex128Array.prototype.get( i )

Returns an array element located at position (index) i.

var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 10 );

// Set the first element:
arr.set( [ 1.0, -1.0 ], 0 );

// Get the first element:
var z = arr.get( 0 );
// returns <Complex128>

var re = real( z );
// returns 1.0

var im = imag( z );
// returns -1.0

If provided an out-of-bounds index, the method returns undefined.

var arr = new Complex128Array( 10 );

var z = arr.get( 100 );
// returns undefined

Complex128Array.prototype.set( z[, i] )

Sets one or more array elements.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 10 );

// Get the first element:
var z = arr.get( 0 );
// returns <Complex128>

var re = real( z );
// returns 0.0

var im = imag( z );
// returns 0.0

// Set the first element:
arr.set( new Complex128( 1.0, -1.0 ) );

// Get the first element:
z = arr.get( 0 );
// returns <Complex128>

re = real( z );
// returns 1.0

im = imag( z );
// returns -1.0

By default, the method sets array elements starting at position (index) i = 0. To set elements starting elsewhere in the array, provide an index argument i.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 10 );

// Get the fifth element:
var z = arr.get( 4 );
// returns <Complex128>

var re = real( z );
// returns 0.0

var im = imag( z );
// returns 0.0

// Set the fifth element:
arr.set( new Complex128( 1.0, -1.0 ), 4 );

// Get the fifth element:
z = arr.get( 4 );
// returns <Complex128>

re = real( z );
// returns 1.0

im = imag( z );
// returns -1.0

In addition to providing a complex number, to set one or more array elements, provide an array-like object containing either complex numbers

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 10 );

// Define an array of complex numbers:
var buf = [
    new Complex128( 1.0, -1.0 ),
    new Complex128( 2.0, -2.0 ),
    new Complex128( 3.0, -3.0 )
];

// Set the fifth, sixth, and seventh elements:
arr.set( buf, 4 );

// Get the sixth element:
var z = arr.get( 5 );
// returns <Complex128>

var re = real( z );
// returns 2.0

var im = imag( z );
// returns -2.0

or interleaved real and imaginary components

var Float64Array = require( '@stdlib/array-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var arr = new Complex128Array( 10 );

// Define an interleaved array of real and imaginary components:
var buf = new Float64Array( [ 1.0, -1.0, 2.0, -2.0, 3.0, -3.0 ] );

// Set the fifth, sixth, and seventh elements:
arr.set( buf, 4 );

// Get the sixth element:
var z = arr.get( 5 );
// returns <Complex128>

var re = real( z );
// returns 2.0

var im = imag( z );
// returns -2.0

A few notes:

  • If i is out-of-bounds, the method throws an error.
  • If a target array cannot accommodate all values (i.e., the length of source array plus i exceeds the target array length), the method throws an error.
  • If provided a typed array which shares an ArrayBuffer with the target array, the method will intelligently copy the source range to the destination range.

Notes

  • While a Complex128Array strives to maintain (but does not guarantee) consistency with typed arrays, significant deviations from ECMAScript-defined typed array behavior are as follows:

    • The constructor does not require the new operator.
    • The constructor and associated methods support a broader variety of input argument types in order to better accommodate complex number input.
    • Accessing array elements using bracket syntax (e.g., Z[i]) is not supported. Instead, one must use the .get() method which returns a value compatible with complex number output.
    • The set method has extended behavior in order to support complex numbers.

Examples

var Complex128 = require( '@stdlib/complex-float64' );
var Float64Array = require( '@stdlib/array-float64' );
var Complex128Array = require( '@stdlib/array-complex128' );

// Create a complex array by specifying a length:
var out = new Complex128Array( 3 );
console.log( out );

// Create a complex array from an array of complex numbers:
var arr = [
    new Complex128( 1.0, -1.0 ),
    new Complex128( -3.14, 3.14 ),
    new Complex128( 0.5, 0.5 )
];
out = new Complex128Array( arr );
console.log( out );

// Create a complex array from an interleaved typed array:
arr = new Float64Array( [ 1.0, -1.0, -3.14, 3.14, 0.5, 0.5 ] );
out = new Complex128Array( arr );
console.log( out );

// Create a complex array from an array buffer:
arr = new Float64Array( [ 1.0, -1.0, -3.14, 3.14, 0.5, 0.5 ] );
out = new Complex128Array( arr.buffer );
console.log( out );

// Create a complex array from an array buffer view:
arr = new Float64Array( [ 1.0, -1.0, -3.14, 3.14, 0.5, 0.5 ] );
out = new Complex128Array( arr.buffer, 16, 2 );
console.log( out );

See Also

Notice

This package is part of 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, see the main project repository.

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License

See LICENSE.

Copyright

Copyright © 2016-2022. The Stdlib Authors.