README.md

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zcopy

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

Usage

import zcopy from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-base-zcopy@esm/index.mjs';

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

Copies values from x into y.

import Complex128Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-complex128@esm/index.mjs';
import real from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-real@esm/index.mjs';
import imag from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-imag@esm/index.mjs';

var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

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

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

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

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

The function has the following parameters:

• N: number of indexed elements.
• x: input Complex128Array.
• strideX: index increment for x.
• y: destination Complex128Array.
• 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,

import Complex128Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-complex128@esm/index.mjs';
import real from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-real@esm/index.mjs';
import imag from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-imag@esm/index.mjs';

var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

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

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

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

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

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

import Complex128Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-complex128@esm/index.mjs';
import real from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-real@esm/index.mjs';
import imag from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-imag@esm/index.mjs';

// Initial arrays...
var x0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y0 = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Create offset views...
var x1 = new Complex128Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Complex128Array( y0.buffer, y0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

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

var z = y0.get( 2 );
// returns <Complex128>

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

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

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

Copies values from x into y using alternative indexing semantics.

import Complex128Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-complex128@esm/index.mjs';
import real from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-real@esm/index.mjs';
import imag from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-imag@esm/index.mjs';

var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

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

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

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

var im = imag( 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],...,

import Complex128Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-complex128@esm/index.mjs';
import real from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-real@esm/index.mjs';
import imag from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-imag@esm/index.mjs';

var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

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

var z = y.get( y.length-1 );
// returns <Complex128>

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

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

Notes

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

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">

import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-discrete-uniform@esm/index.mjs';
import filledarrayBy from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-filled-by@esm/index.mjs';
import Complex128 from 'https://cdn.jsdelivr.net/gh/stdlib-js/complex-float64-ctor@esm/index.mjs';
import zcopy from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-base-zcopy@esm/index.mjs';

function rand() {
    return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}

var x = filledarrayBy( 10, 'complex128', rand );
console.log( x.get( 0 ).toString() );

var y = filledarrayBy( 10, 'complex128', rand );
console.log( y.get( 0 ).toString() );

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

</script>
</body>
</html>

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Notice

This package is part of stdlib, a standard library 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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.