code: def minOpar(self,dangle,tdisrupt=None,_return_raw=False):
          
          if tdisrupt is None: tdisrupt= self._tdisrupt
          # First construct the breakpoints for this dangle
          Oparb= (dangle-self._kick_interpdOpar_poly.x[:-1])/self._timpact
          # Find the lower limit of the integration in the pw-linear-kick approx.
          lowx= ((Oparb-self._kick_interpdOpar_poly.c[-1])\
                     *(tdisrupt-self._timpact)+Oparb*self._timpact-dangle)\
                     /((tdisrupt-self._timpact)\
                           *(1.+self._kick_interpdOpar_poly.c[-2]*self._timpact)\
                           +self._timpact)
          lowx[lowx < 0.]= numpy.inf
          lowbindx= numpy.argmin(lowx)
          if _return_raw:
              return (lowbindx,lowx[lowbindx])
          else:
              return Oparb[lowbindx]-lowx[lowbindx]
docs: NAME:
  
             minOpar
  
          PURPOSE:
  
             return the approximate minimum parallel frequency at a given angle
  
          INPUT:
  
             dangle - parallel angle
  
          OUTPUT:
  
             minimum frequency that gets to this parallel angle
  
          HISTORY:
  
             2015-12-28 - Written - Bovy (UofT)