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!
Applies a plane rotation.
npm install @stdlib/blas-base-zdrot
Alternatively,
- To load the package in a website via a
script
tag without installation and bundlers, use the ES Module available on theesm
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.
var zdrot = require( '@stdlib/blas-base-zdrot' );
Applies a plane rotation.
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 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
zdrot( zx.length, zx, 1, zy, 1, 0.8, 0.6 );
var z = zy.get( 0 );
// returns <Complex128>
var re = real( z );
// returns ~-0.6
var im = imag( z );
// returns ~-1.2
z = zx.get( 0 );
// returns <Complex128>
re = real( z );
// returns ~0.8
im = imag( z );
// returns ~1.6
The function has the following parameters:
- N: number of indexed elements.
- zx: first input
Complex128Array
. - strideX: index increment for
zx
. - zy: second input
Complex128Array
. - strideY: index increment for
zy
.
The N
and stride parameters determine how values from zx
and zy
are accessed at runtime. For example, to apply a plane rotation to every other 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 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
zdrot( 2, zx, 2, zy, 2, 0.8, 0.6 );
var z = zy.get( 0 );
// returns <Complex128>
var re = real( z );
// returns ~-0.6
var im = imag( z );
// returns ~-1.2
z = zx.get( 0 );
// returns <Complex128>
re = real( z );
// returns ~0.8
im = imag( z );
// returns ~1.6
Note that indexing is relative to the first index. To introduce an offset, use typed array
views.
var Complex128Array = require( '@stdlib/array-complex128' );
var real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );
// Initial arrays...
var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy0 = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
// Create offset views...
var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var zy1 = new Complex128Array( zy0.buffer, zy0.BYTES_PER_ELEMENT*2 ); // start at 3rd element
zdrot( 2, zx1, -2, zy1, 1, 0.8, 0.6 );
var z = zy0.get( 2 );
// returns <Complex128>
var re = real( z );
// returns ~-4.2
var im = imag( z );
// returns ~-4.8
z = zx0.get( 3 );
// returns <Complex128>
re = real( z );
// returns ~5.6
im = imag( z );
// returns ~6.4
Applies a plane rotation 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 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
zdrot.ndarray( zx.length, zx, 1, 0, zy, 1, 0, 0.8, 0.6 );
var z = zy.get( 0 );
// returns <Complex128>
var re = real( z );
// returns ~-0.6
var im = imag( z );
// returns ~-1.2
z = zx.get( 0 );
// returns <Complex128>
re = real( z );
// returns ~0.8
im = imag( z );
// returns ~1.6
The function has the following additional parameters:
- offsetX: starting index for
zx
. - offsetY: starting index for
zy
.
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 apply a plane rotation to every other element 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 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
zdrot.ndarray( 2, zx, 2, 1, zy, 2, 1, 0.8, 0.6 );
var z = zy.get( 3 );
// returns <Complex128>
var re = real( z );
// returns ~-4.2
var im = imag( z );
// returns ~-4.8
z = zx.get( 1 );
// returns <Complex128>
re = real( z );
// returns ~2.4
im = imag( z );
// returns ~3.2
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var zcopy = require( '@stdlib/blas-base-zcopy' );
var zeros = require( '@stdlib/array-zeros' );
var logEach = require( '@stdlib/console-log-each' );
var zdrot = require( '@stdlib/blas-base-zdrot' );
function rand() {
return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}
// Generate random input arrays:
var zx = filledarrayBy( 10, 'complex128', rand );
var zxc = zcopy( zx.length, zx, 1, zeros( zx.length, 'complex128' ), 1 );
var zy = filledarrayBy( 10, 'complex128', rand );
var zyc = zcopy( zy.length, zy, 1, zeros( zy.length, 'complex128' ), 1 );
// Apply a plane rotation:
zdrot( zx.length, zx, 1, zy, 1, 0.8, 0.6 );
// Print the results:
logEach( '(%s,%s) => (%s,%s)', zxc, zyc, zx, zy );
#include "stdlib/blas/base/zdrot.h"
Applies a plane rotation.
double x[] = { 1.0, 2.0, 3.0, 4.0 }; // interleaved real and imaginary components
double y[] = { 5.0, 6.0, 7.0, 8.0 };
c_zdrot( 2, (void *)x, 1, (void *)Y, 1, 0.8, 0.6 );
The function accepts the following arguments:
- N:
[in] CBLAS_INT
number of indexed elements. - zx:
[inout] void*
first input array. - strideX:
[in] CBLAS_INT
index increment forzx
. - zy:
[inout] void*
second input array. - strideY:
[in] CBLAS_INT
index increment forzy
. - c:
[in] double
cosine of the angle of rotation. - s:
[in] double
sine of the angle of rotation.
void c_zdrot( const CBLAS_INT N, void *X, const CBLAS_INT strideX, void *Y, const CBLAS_INT strideY, const double c, const double s );
#include "stdlib/blas/base/zdrot.h"
#include <stdio.h>
int main( void ) {
// Create strided arrays:
double zx[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };
double zy[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
// Specify the number of elements:
const int N = 4;
// Specify stride lengths:
const int strideX = 1;
const int strideY = -1;
// Copy elements:
c_zdrot( N, (void *)zx, strideX, (void *)zy, strideY, 0.8, 0.6 );
// Print the result:
for ( int i = 0; i < N; i++ ) {
printf( "zx[ %i ] = %lf + %lfj\n", i, zx[ i*2 ], zx[ (i*2)+1 ] );
printf( "zy[ %i ] = %lf + %lfj\n", i, zy[ i*2 ], zy[ (i*2)+1 ] );
}
}
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.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.