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zlacgv

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

Installation

npm install @stdlib/lapack-base-zlacgv

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

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

zlacgv( 2, zx, 1 );

var z = zx.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.
• 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 real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );

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>

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

var im = imag( z );
// returns -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' );
var real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );

// 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>

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

var im = imag( z );
// returns -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 real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );

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>

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

var im = imag( z );
// returns -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 real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );

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>

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

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

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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

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License

See LICENSE.

Copyright

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