cflipsign

Return a double-precision complex floating-point number with the same magnitude as z and the sign of y*z.

Installation

npm install @stdlib/math-base-special-cflipsign

Usage

var cflipsign = require( '@stdlib/math-base-special-cflipsign' );

cflipsign( z, y )

Returns a double-precision complex floating-point number with the same magnitude as z and the sign of y*z.

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

var v = cflipsign( new Complex128( -4.2, 5.5 ), -1.0 );
// returns <Complex128>

var re = real( v );
// returns 4.2

var im = imag( v );
// returns -5.5

Examples

var uniform = require( '@stdlib/random-base-uniform' ).factory;
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var cflipsign = require( '@stdlib/math-base-special-cflipsign' );

var rand = uniform( -50.0, 50.0 );

var z;
var y;
var i;
for ( i = 0; i < 100; i++ ) {
    z = new Complex128( rand(), rand() );
    y = rand();
    console.log( 'cflipsign(%s, %d) = %s', z, y, cflipsign( z, y ) );
}

C APIs

Usage

#include "stdlib/math/base/special/cflipsign.h"

stdlib_base_cflipsign( z, y )

Returns a double-precision complex floating-point number with the same magnitude as z and the sign of y*z.

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

stdlib_complex128_t z = stdlib_complex128( 2.5, -1.5 );

stdlib_complex128_t out = stdlib_base_cflipsign( z, -1.0 );

double re = stdlib_complex128_real( out );
// returns -2.5

double im = stdlib_complex128_imag( out );
// returns 1.5

The function accepts the following arguments:

• z: [in] stdlib_complex128_t input value.
• y: [in] double number from which to derive the sign.

stdlib_complex128_t stdlib_base_cflipsign( const stdlib_complex128_t z, const double y );

Examples

#include "stdlib/math/base/special/cflipsign.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 re1;
    double im1;
    double re2;
    double im2;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        y = stdlib_base_cflipsign( v, -1.0 );
        stdlib_complex128_reim( v, &re1, &im1 );
        stdlib_complex128_reim( y, &re2, &im2 );
        printf( "cflipsign(%lf + %lfi, %lf) = %lf + %lfi\n", re1, im1, -1.0, re2, im2 );
}

See Also

• @stdlib/math-base/ops/cneg: negate a double-precision complex floating-point number.
• @stdlib/math-base/special/csignum: evaluate the signum function of a double-precision complex floating-point number.

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 © 2016-2024. The Stdlib Authors.