lcv matches those for the
  locfit or locfit.raw functions.
  The fit is not returned; instead, the returned object contains
  likelihood cross validation score for the fit.  The LCV score is exact (up to numerical roundoff) if the
  ev="cross" argument is provided. Otherwise, the influence
  and cross validated residuals
  are computed using locfit's
  standard interpolation based approximations.
lcv(x, ...)locfit,
  locfit.raw,
  lcvplot