You can use the Method tab to specify options for the thin-plate spline algorithm. (See Figure 19.5.) The Method tab contains the following UI controls:
- Selection method
-
specifies how to choose the smoothing penalty parameter. This option corresponds to the SELECT= option in the MODEL statement.
- GCV
-
selects the smoothing parameter that minimizes the generalized cross validation criterion.
- Approx. model DF
-
selects the smoothing parameter for which the trace of the prediction matrix is closest to the Target model DF. This corresponds to SELECT=DF option.
- Manual
-
enables you to specify the value in the log(n*lambda) field. This corresponds to the LOGNLAMBDA= option.
- Maximum number of unique design points
-
specifies a limit on the number of unique design points,
, in the model. This option corresponds to the DISTANCE= option in the MODEL statement in the following way: the value in
this field is used to compute a value for the DISTANCE= option so that there are at most design points. This option is useful for large data sets, since the TPSPLINE procedure is computationally expensive.
