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Scales a single-precision complex floating-point vector by a single-precision complex floating-point constant.
npm install @stdlib/blas-base-cscal
Alternatively,
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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
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branch (see README).
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var cscal = require( '@stdlib/blas-base-cscal' );
Scales values from cx
by ca
.
var Complex64Array = require( '@stdlib/array-complex64' );
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );
var cx = new Complex64Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var ca = new Complex64( 2.0, 0.0 );
cscal( 3, ca, cx, 1 );
var z = cx.get( 0 );
// returns <Complex64>
var re = realf( z );
// returns 2.0
var im = imagf( z );
// returns 2.0
The function has the following parameters:
- N: number of indexed elements.
- ca: scalar
Complex64
constant. - cx: input
Complex64Array
. - strideX: index increment for
cx
.
The N
and stride parameters determine how values from cx
are scaled by ca
. For example, to scale every other value in cx
by ca
,
var Complex64Array = require( '@stdlib/array-complex64' );
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );
var cx = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var ca = new Complex64( 2.0, 0.0 );
cscal( 2, ca, cx, 2 );
var z = cx.get( 2 );
// returns <Complex64>
var re = realf( z );
// returns 10.0
var im = imagf( z );
// returns 12.0
Note that indexing is relative to the first index. To introduce an offset, use typed array
views.
var Complex64Array = require( '@stdlib/array-complex64' );
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );
// Initial array:
var cx0 = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
// Define a scalar constant:
var ca = new Complex64( 2.0, 2.0 );
// Create an offset view:
var cx1 = new Complex64Array( cx0.buffer, cx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
// Scales every other value from `cx1` by `ca`...
cscal( 3, ca, cx1, 1 );
var z = cx0.get( 1 );
// returns <Complex64>
var re = realf( z );
// returns -2.0
var im = imagf( z );
// returns 14.0
Scales values from cx
by ca
using alternative indexing semantics.
var Complex64Array = require( '@stdlib/array-complex64' );
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );
var cx = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var ca = new Complex64( 2.0, 2.0 );
cscal.ndarray( 3, ca, cx, 1, 0 );
var z = cx.get( 0 );
// returns <Complex64>
var re = realf( z );
// returns -2.0
var im = imagf( z );
// returns 6.0
The function has the following additional parameters:
- offsetX: starting index for
cx
.
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 scale every other value in the input strided array starting from the second element,
var Complex64Array = require( '@stdlib/array-complex64' );
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var realf = require( '@stdlib/complex-float32-real' );
var imagf = require( '@stdlib/complex-float32-imag' );
var cx = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var ca = new Complex64( 2.0, 2.0 );
cscal.ndarray( 2, ca, cx, 2, 1 );
var z = cx.get( 3 );
// returns <Complex64>
var re = realf( z );
// returns -2.0
var im = imagf( z );
// returns 30.0
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var Complex64 = require( '@stdlib/complex-float32-ctor' );
var cscal = require( '@stdlib/blas-base-cscal' );
function rand() {
return new Complex64( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}
var cx = filledarrayBy( 10, 'complex64', rand );
console.log( cx.toString() );
var ca = new Complex64( 2.0, 2.0 );
console.log( ca.toString() );
// Scale elements from `cx` by `ca`:
cscal( cx.length, ca, cx, 1 );
console.log( cx.get( cx.length-1 ).toString() );
#include "stdlib/blas/base/cscal.h"
Scales values from CX
by ca
.
#include "stdlib/complex/float32/ctor.h"
float cx[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
const stdlib_complex64_t ca = stdlib_complex64( 2.0f, 2.0f );
c_dscal( 4, ca, (void *)cx, 1 );
The function accepts the following arguments:
- N:
[in] CBLAS_INT
number of indexed elements. - ca:
[in] stdlib_complex64_t
scalar constant. - CX:
[inout] void*
input array. - strideX:
[in] CBLAS_INT
index increment forCX
.
void c_dscal( const CBLAS_INT N, const stdlib_complex64_t ca, void *CX, const CBLAS_INT strideX );
#include "stdlib/blas/base/cscal.h"
#include "stdlib/complex/float32/ctor.h"
#include <stdio.h>
int main( void ) {
// Create a strided array of interleaved real and imaginary components:
float cx[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
// Create a complex scalar:
const stdlib_complex64_t ca = stdlib_complex64( 2.0f, 2.0f );
// Specify the number of elements:
const int N = 4;
// Specify stride length:
const int strideX = 1;
// Scale the elements of the array:
c_cscal( N, ca, (void *)cx, strideX );
// Print the result:
for ( int i = 0; i < N; i++ ) {
printf( "cx[ %i ] = %f + %fj\n", i, cx[ i*2 ], cx[ (i*2)+1 ] );
}
}
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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.
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