a,
           but use leave-one-out cross validation), 'none' (no evaluation
           points, effectively producing the global parametric fit).
           Alternatively, a vector/matrix of evaluation points may be
           provided. 
           (kd trees not currently supported in mlocfit)
     'll' and 'ur' -- row vectors specifying the upper and lower limits
           for the bounding box used by the evaluation structure.
           They default to the data range. 
     'mg' For the 'grid' e