zlacgv

Conjugate each element in a double-precision complex floating-point vector.

Installation

npm install @stdlib/lapack-base-zlacgv

Usage

var zlacgv = require( '@stdlib/lapack-base-zlacgv' );

zlacgv( N, zx, strideZX )

Conjugates each element in a double-precision complex floating-point vector.

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

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0 ] );

zlacgv( 2, zx, 1 );

var z = zx.get( 0 );
// returns <Complex128>[ 1.0, -2.0 ]

The function has the following parameters:

• N: number of indexed elements.
• zx: input Complex128Array.
• strideZX: stride length for zx.

The N and stride parameters determine which elements in zx are conjugated. For example, to conjugate every other element in zx,

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

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

zlacgv( 2, zx, 2 );

var z = zx.get( 0 );
// returns <Complex128>[ 1.0, -2.0 ]

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

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

// Initial array:
var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );

// Create an offset view:
var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Conjugate every element in `zx1`:
zlacgv( 3, zx1, 1 );

var z = zx0.get( 1 );
// returns <Complex128>[ 3.0, -4.0 ]

zlacgv.ndarray( N, zx, strideZX, offsetZX )

Conjugates each element in a double-precision floating-point vector using alternative indexing semantics.

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

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

zlacgv.ndarray( 3, zx, 1, 0 );

var z = zx.get( 0 );
// returns <Complex128>[ 1.0, -2.0 ]

The function has the following additional parameters:

• offsetZX: starting index for zx.

While typed array views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to conjugate every other element in the input strided array starting from the second element,

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

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

zlacgv.ndarray( 2, zx, 2, 1 );

var z = zx.get( 3 );
// returns <Complex128>[ 7.0, -8.0 ]

Notes

• If N <= 0, both functions return zx unchanged.
• zlacgv() corresponds to the LAPACK BLAS-like level 1 routine zlacgv.

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zlacgv = require( '@stdlib/lapack-base-zlacgv' );

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

var zx = filledarrayBy( 10, 'complex128', rand );
console.log( zx.toString() );

// Conjugate elements:
zlacgv( zx.length, zx, 1 );
console.log( zx.get( zx.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.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.