code: def JR(self,**kwargs):
          
          if hasattr(self,'_JR'): #pragma: no cover
              return self._JR
          (rperi,rap)= self.calcRapRperi(**kwargs)
          EL= self.calcEL(**kwargs)
          E, L= EL
          self._JR= 1./nu.pi*integrate.quad(_JRAxiIntegrand,rperi,rap,
                                            args=(E,L,self._pot),
                                            **kwargs)[0]
          return self._JR
docs: NAME:
             JR
          PURPOSE:
             Calculate the radial action
          INPUT:
             +scipy.integrate.quad keywords
          OUTPUT:
             J_R(R,vT,vT)/ro/vc + estimate of the error
          HISTORY:
             2010-12-01 - Written - Bovy (NYU)