About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

cswap

Interchange two complex single-precision floating-point vectors.

Installation

npm install @stdlib/blas-base-cswap

Alternatively,

To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
If you are using Deno, visit the deno branch (see README for usage intructions).
For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

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

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

Interchanges two complex single-precision floating-point vectors.

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );

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 ] );

cswap( 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

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

re = realf( z );
// returns 0.0

im = imagf( z );
// returns 0.0

The function has the following parameters:

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

The N and stride parameters determine how values from x are interchanged with values from y. For example, to interchange 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-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );

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 ] );

cswap( 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

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

re = realf( z );
// returns 0.0

im = imagf( z );
// returns 0.0

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-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );

// 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

// Interchange in reverse order every other value from `x1` into `y1`...
cswap( 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

z = x0.get( 1 );
// returns <Complex64>

re = realf( z );
// returns 0.0

im = imagf( z );
// returns 0.0

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

Interchanges two complex single-precision floating-point vectors using alternative indexing semantics.

var Complex64Array = require( '@stdlib/array-complex64' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );

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 ] );

cswap.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

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

re = realf( z );
// returns 0.0

im = imagf( z );
// returns 0.0

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 interchange 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-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );

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 ] );

cswap.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

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

re = realf( z );
// returns 0.0

im = imagf( z );
// returns 0.0

Notes

If N <= 0, both functions leave x and y unchanged.
cswap() corresponds to the BLAS level 1 function cswap.

Examples

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

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() );

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

C APIs

Usage

#include "stdlib/blas/base/cswap.h"

c_cswap( N, X, strideX, Y, strideY )

Interchanges two complex single-precision floating-point vectors.

float x[] = { 1.0f, 2.0f, 3.0f, 4.0f }; // interleaved real and imaginary components
float y[] = { 5.0f, 6.0f, 7.0f, 8.0f };

c_cswap( 2, (void *)x, 1, (void *)Y, 1 );

The function accepts the following arguments:

N: [in] CBLAS_INT number of indexed elements.
X: [inout] void* first input array.
strideX: [in] CBLAS_INT index increment for X.
Y: [inout] void* first input array.
strideY: [in] CBLAS_INT index increment for Y.

void c_cswap( const CBLAS_INT N, void *X, const CBLAS_INT strideX, void *Y, const CBLAS_INT strideY );

Examples

#include "stdlib/blas/base/cswap.h"
#include <stdio.h>

int main( void ) {
    // Create strided arrays:
    float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
    float y[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

    // Specify the number of elements:
    const int N = 4;

    // Specify stride lengths:
    const int strideX = 1;
    const int strideY = -1;

    // Copy elements:
    c_cswap( N, (void *)x, strideX, (void *)y, strideY );

    // Print the result:
    for ( int i = 0; i < N; i++ ) {
        printf( "x[ %i ] = %f + %fj\n", i, x[ i*2 ], x[ (i*2)+1 ] );
        printf( "y[ %i ] = %f + %fj\n", i, y[ i*2 ], y[ (i*2)+1 ] );
    }
}

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.

Community

License

See LICENSE.

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

README.md

README.md

cswap

Installation

Usage

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

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

Notes

Examples

C APIs

Usage

c_cswap( N, X, strideX, Y, strideY )

Examples

See Also

Notice

Community

License

Copyright

Files

README.md

Latest commit

History

README.md

File metadata and controls

cswap

Installation

Usage

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

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

Notes

Examples

C APIs

Usage

c_cswap( N, *X, strideX, *Y, strideY )

Examples

See Also

Notice

Community

License

Copyright

c_cswap( N, X, strideX, Y, strideY )