.

   'deg' Degree of local polynomial. Default: 2 (local quadratic).
         Degrees 0 to 3 are supported by almost all parts of the
         Locfit code. Higher degrees may work in some cases. 
 
  'kern' Weight function, default = 'tcub'. Other choices are
         'rect', 'trwt', 'tria', 'epan', 'bisq' and 'gauss'.
         Choices may be restricted when derivatives are
         required; e.g. for confidence bands and some bandwidth
         selectors. 
 
    'kt' Kernel type, 'sph' (defaul