) than the data. Warnings aside...

  'deriv' Derivative estimation. 'deriv',1 specifies the first derivative
         (or more correctly, an estimate of the local slope is returned.
         'deriv',[1 1] specifies the second derivative. For bivariate fits
         'deriv',2 specifies the first partial derivative wrt x2.
         'deriv',[1 2] is mixed second-order derivative.
 
  Fitting family.
  'family' is used to specify the local likelihood family.
         Regression-type families are 'gau