valuation structure, 'mg' specifies the
           number of points on each margin. Default 10. Can be either a
           single number or vector. 
    'cut' Refinement parameter for adaptive partitions. Default 0.8;
           smaller values result in more refined partitions. 
    'maxk' Controls space assignment for evaluation structures. For the
           adaptive evaluation structures, it is impossible to be sure
           in advance how many vertices will be generated. If you get
           