(X, r=1)
return result
It implements the following formula:

        .. math::
            \\varphi(\\boldsymbol{x}) = \\sqrt{\\boldsymbol{x}^2 + r^2}

        :param numpy.ndarray X: the norm x in the formula above.
        :param float r: the parameter r in the formula above.

        :return: result: the result of the formula above.
        :rtype: float
It implements the following formula:
It implements the following formula :
def multi_quadratic_biharmonic_spline(X, r=1):
        """
        It implements the following formula:

        .. math::
            \\varphi(\\boldsymbol{x}) = \\sqrt{\\boldsymbol{x}^2 + r^2}

        :param numpy.ndarray X: the norm x in the formula above.
        :param float r: the parameter r in the formula above.

        :return: result: the result of the formula above.
        :rtype: float
        """
        result = np.sqrt((X * X) + (r * r))
        return result
def multi_quadratic_biharmonic_spline ( X , r = 1 ) : result = np . sqrt ( ( X * X ) + ( r * r ) ) return result