Skip to content

scale

Directory actions

More options

Directory actions

More options

Latest commit

 

History

History
 
 

scale

README.md

scale

Scale a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.

Usage

var scale = require( '@stdlib/complex/float64/base/scale' );

scale( alpha, z )

Scales a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.

var Complex128 = require( '@stdlib/complex/float64/ctor' );
var real = require( '@stdlib/complex/float64/real' );
var imag = require( '@stdlib/complex/float64/imag' );

var z = new Complex128( 5.0, 3.0 );

var v = scale( 5.0, z );
// returns <Complex128>

var re = real( v );
// returns 25.0

var im = imag( v );
// returns 15.0

The function supports the following parameters:

scale.assign( alpha, re1, im1, out, strideOut, offsetOut )

Scales a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant and assigns results to a provided output array.

var Float64Array = require( '@stdlib/array/float64' );

var out = new Float64Array( 2 );
var v = scale.assign( 5.0, 5.0, 3.0, out, 1, 0 );
// returns <Float64Array>[ 25.0, 15.0 ]

var bool = ( out === v );
// returns true

The function supports the following parameters:

  • alpha: real-valued scalar constant.
  • re: real component of the complex number.
  • im: imaginary component of the complex number.
  • out: output array.
  • strideOut: stride length for out.
  • offsetOut: starting index for out.

scale.strided( alpha, z, sz, oz, out, so, oo )

Scales a double-precision complex floating-point number stored in a real-valued strided array view by a real-valued double-precision floating-point scalar constant and assigns results to a provided strided output array.

var Float64Array = require( '@stdlib/array/float64' );

var z = new Float64Array( [ 5.0, 3.0 ] );
var out = new Float64Array( 2 );

var v = scale.strided( 5.0, z, 1, 0, out, 1, 0 );
// returns <Float64Array>[ 25.0, 15.0 ]

var bool = ( out === v );
// returns true

The function supports the following parameters:

  • alpha: real-valued scalar constant.
  • z: complex number strided array view.
  • sz: stride length for z.
  • oz: starting index for z.
  • out: output array.
  • so: stride length for out.
  • oo: starting index for out.

Examples

var Complex128 = require( '@stdlib/complex/float64/ctor' );
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
var scale = require( '@stdlib/complex/float64/base/scale' );

var rand = discreteUniform( -50, 50 );

var z1;
var z2;
var i;
for ( i = 0; i < 100; i++ ) {
    z1 = new Complex128( rand(), rand() );
    z2 = scale( 5.0, z1 );
    console.log( '(%s) * 5.0 = %s', z1.toString(), z2.toString() );
}

C APIs

Usage

#include "stdlib/complex/float64/base/scale.h"

stdlib_base_complex128_scale( alpha, z )

Scales a double-precision complex floating-point number by a real-valued double-precision floating-point scalar constant.

#include "stdlib/complex/float64/ctor.h"
#include "stdlib/complex/float64/real.h"
#include "stdlib/complex/float64/imag.h"

stdlib_complex128_t z = stdlib_complex128( 5.0, 3.0 );

stdlib_complex128_t out = stdlib_base_complex128_scale( 5.0, z );

double re = stdlib_complex128_real( out );
// returns 25.0

double im = stdlib_complex128_imag( out );
// returns 15.0

The function accepts the following arguments:

  • alpha: [in] double scalar constant.
  • z: [in] stdlib_complex128_t complex number.
stdlib_complex128_t stdlib_base_complex128_scale( const double alpha, const stdlib_complex128_t z );

Examples

#include "stdlib/complex/float64/base/scale.h"
#include "stdlib/complex/float64/ctor.h"
#include "stdlib/complex/float64/reim.h"
#include <stdio.h>

int main( void ) {
    const stdlib_complex128_t x[] = {
        stdlib_complex128( 3.14, 1.5 ),
        stdlib_complex128( -3.14, 1.5 ),
        stdlib_complex128( 0.0, -0.0 ),
        stdlib_complex128( 0.0/0.0, 0.0/0.0 )
    };

    stdlib_complex128_t v;
    stdlib_complex128_t y;
    double re;
    double im;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        stdlib_complex128_reim( v, &re, &im );
        printf( "z = %lf + %lfi\n", re, im );

        y = stdlib_base_complex128_scale( 5.0, v );
        stdlib_complex128_reim( y, &re, &im );
        printf( "scale(5.0, z) = %lf + %lfi\n", re, im );
    }
}