cphase

Compute the argument of a double-precision complex floating-point number in radians.

The argument of a complex number, also known as the phase, is the angle of the radius extending from the origin to the complex number plotted in the complex plane and the positive real axis.

Usage

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

cphase( z )

Computes the argument of a double-precision complex floating-point number.

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

var phi = cphase( new Complex128( 5.0, 3.0 ) );
// returns ~0.5404

Examples

var Complex128 = require( '@stdlib/complex/float64/ctor' );
var uniform = require( '@stdlib/random/base/uniform' );
var cphase = require( '@stdlib/math/base/special/cphase' );

var z;
var i;

for ( i = 0; i < 100; i++ ) {
    z = new Complex128( uniform( -500.0, 500.0 ), uniform( -500.0, 500.0 ) );
    console.log( 'arg(%s) = %d', z.toString(), cphase( z ) );
}

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C APIs

Usage

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

stdlib_base_cphase( z )

Computes the argument of a double-precision complex floating-point number.

#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 );
double out = stdlib_base_cphase( z );
// returns ~0.5404

The function accepts the following arguments:

• z: [in] stdlib_complex128_t input value.

double stdlib_base_cphase( const stdlib_complex128_t z );

Examples

#include "stdlib/math/base/special/cphase.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_cphase( v );
        stdlib_complex128_reim( v, &re1, &im1 );
        stdlib_complex128_reim( y, &re2, &im2 );
        printf( "cphase(%lf + %lfi) = %lf\n", re, im, y );
    }
}

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See Also

• @stdlib/math/base/special/cabs: compute the absolute value of a double-precision complex floating-point number.