def reverse(self):
        """
        NAME:

           reverse

        PURPOSE:

           reverse an already integrated orbit (that is, make it go from end to beginning in t=0 to tend)

        INPUT:

           (none)

        OUTPUT:

           (none)

        HISTORY:
           2011-04-13 - Written - Bovy (NYU)
        """
        if hasattr(self,'_orbInterp'): delattr(self,'_orbInterp')
        if hasattr(self,'rs'): delattr(self,'rs')
        sortindx = list(range(len(self._orb.t)))
        sortindx.sort(key=lambda x: self._orb.t[x],reverse=True)
        for ii in range(self._orb.orbit.shape[1]):
            self._orb.orbit[:,ii]= self._orb.orbit[sortindx,ii]
        return None
NAME:

           reverse

        PURPOSE:

           reverse an already integrated orbit (that is, make it go from end to beginning in t=0 to tend)

        INPUT:

           (none)

        OUTPUT:

           (none)

        HISTORY:
           2011-04-13 - Written - Bovy (NYU)