php/vendor/markbaker/complex/classes/src/functions/rho.php

<?php

/**
 *
 * Function code for the complex rho() function
 *
 * @copyright  Copyright (c) 2013-2018 Mark Baker (https://github.com/MarkBaker/PHPComplex)
 * @license    https://opensource.org/licenses/MIT    MIT
 */
namespace Complex;

/**
 * Returns the rho of a complex number.
 * This is the distance/radius from the centrepoint to the representation of the number in polar coordinates.
 *
 * @param     Complex|mixed    $complex    Complex number or a numeric value.
 * @return    float            The rho value of the complex argument.
 * @throws    Exception        If argument isn't a valid real or complex number.
 */
if (!function_exists(__NAMESPACE__ . '\\rho')) {
    function rho($complex): float
    {
        $complex = Complex::validateComplexArgument($complex);

        return \sqrt(
            ($complex->getReal() * $complex->getReal()) +
            ($complex->getImaginary() * $complex->getImaginary())
        );
    }
}