@stdlib/blas-base-ccopy NPM

ccopy

Copy values from one complex single-precision floating-point vector to another complex single-precision floating-point vector.

Installation

npm install @stdlib/blas-base-ccopy

Usage

var ccopy = require( '@stdlib/blas-base-ccopy' );

ccopy( N, x, strideX, y, strideY )

Copies values from x into y.

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-realf' );
var imagf = require( '@stdlib/complex-imagf' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy( x.length, x, 1, y, 1 );

var z = y.get( 0 );
// returns <Complex64>

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

var im = imagf( z );
// returns 2.0

The function has the following parameters:

N: number of indexed elements.
x: input Complex64Array.
strideX: index increment for x.
y: destination Complex64Array.
strideY: index increment for y.

The N and stride parameters determine how values from x are copied into y. For example, to copy in reverse order every other value in x into the first N elements of y,

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-realf' );
var imagf = require( '@stdlib/complex-imagf' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy( 2, x, -2, y, 1 );

var z = y.get( 0 );
// returns <Complex64>

var re = realf( z );
// returns 5.0

var im = imagf( z );
// returns 6.0

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-realf' );
var imagf = require( '@stdlib/complex-imagf' );

// Initial arrays...
var x0 = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y0 = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Create offset views...
var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Complex64Array( y0.buffer, y0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

// Copy in reverse order every other value from `x1` into `y1`...
ccopy( 2, x1, -2, y1, 1 );

var z = y0.get( 2 );
// returns <Complex64>

var re = realf( z );
// returns 7.0

var im = imagf( z );
// returns 8.0

ccopy.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )

Copies values from x into y using alternative indexing semantics.

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-realf' );
var imagf = require( '@stdlib/complex-imagf' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy.ndarray( x.length, x, 1, 0, y, 1, 0 );

var z = y.get( 0 );
// returns <Complex64>

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

var im = imagf( z );
// returns 2.0

The function has the following additional parameters:

offsetX: starting index for x.
offsetY: starting index for y.

While typed array views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, to copy every other value in x starting from the second value into the last N elements in y where x[i] = y[n], x[i+2] = y[n-1],...,

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-realf' );
var imagf = require( '@stdlib/complex-imagf' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy.ndarray( 2, x, 2, 1, y, -1, y.length-1 );

var z = y.get( y.length-1 );
// returns <Complex64>

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

var im = imagf( z );
// returns 4.0

Notes

If N <= 0, both functions return y unchanged.
ccopy() corresponds to the BLAS level 1 function ccopy.

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var Complex64 = require( '@stdlib/complex-float32' );
var ccopy = require( '@stdlib/blas-base-ccopy' );

function rand() {
    return new Complex64( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}

var x = filledarrayBy( 10, 'complex64', rand );
console.log( x.get( 0 ).toString() );

var y = filledarrayBy( 10, 'complex64', rand );
console.log( y.get( 0 ).toString() );

// Copy elements from `x` into `y` starting from the end of `y`:
ccopy( x.length, x, 1, y, -1 );
console.log( y.get( y.length-1 ).toString() );

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.