def pangledAngle(self,angleperp,dangle,smallest=False):
        """
        NAME:

           pangledAngle

        PURPOSE:
           return the probability of a given perpendicular angle  at a given angle along the stream

        INPUT:

           angleperp - perpendicular angle

           dangle - angle offset along the stream

           smallest= (False) calculate for smallest eigenvalue direction rather than for middle

        OUTPUT:

           p(angle_perp|dangle)

        HISTORY:

           2013-12-06 - Written - Bovy (IAS)

        """
        if isinstance(angleperp,(int,float,numpy.float32,numpy.float64)):
            angleperp= numpy.array([angleperp])
        out= numpy.zeros(len(angleperp))
        out= numpy.array([\
                integrate.quad(self._pangledAnglet,0.,self._tdisrupt,
                               (ap,dangle,smallest))[0] for ap in angleperp])
        return out
NAME:

           pangledAngle

        PURPOSE:
           return the probability of a given perpendicular angle  at a given angle along the stream

        INPUT:

           angleperp - perpendicular angle

           dangle - angle offset along the stream

           smallest= (False) calculate for smallest eigenvalue direction rather than for middle

        OUTPUT:

           p(angle_perp|dangle)

        HISTORY:

           2013-12-06 - Written - Bovy (IAS)