(self)
return Point.distance(self.center, self.foci[0])
The focale distance of the ellipse.

        The distance between the center and one focus.

        Returns
        =======

        focus_distance : number

        See Also
        ========

        foci

        Examples
        ========

        >>> from sympy import Point, Ellipse
        >>> p1 = Point(0, 0)
        >>> e1 = Ellipse(p1, 3, 1)
        >>> e1.focus_distance
        2*sqrt(2)
The focale distance of the ellipse.
The focale distance of the ellipse .
def focus_distance(self):
        """The focale distance of the ellipse.

        The distance between the center and one focus.

        Returns
        =======

        focus_distance : number

        See Also
        ========

        foci

        Examples
        ========

        >>> from sympy import Point, Ellipse
        >>> p1 = Point(0, 0)
        >>> e1 = Ellipse(p1, 3, 1)
        >>> e1.focus_distance
        2*sqrt(2)

        """
        return Point.distance(self.center, self.foci[0])
def focus_distance ( self ) : return Point . distance ( self . center , self . foci [ 0 ] )