Model Browser User's Guide

Tips for Modeling with Radial Basis Functions

Plan of Attack

Determine which parameters have the most impact on the fit by following these steps:

1. Fit the default RBF. Remove any obvious outliers.
2. Get a rough idea of how many RBFs are going to be needed.
3. ry with more than one kernel.
4. Decide on the main width selection algorithm. Try with both TrialWidths and WidPerDim algorithms.
5. Determine which types of kernel look most hopeful.
6. Narrow the corresponding width range to search over.
7. Decide on the center selection algorithm.
8. Decide on the lambda-selection algorithm.
9. Try changing the parameters in the algorithms.
10. If any points appear to be possible outliers, try fitting the model both with and without those points.

If at any stage you decide on a change that has a big impact (such as removal of an outlier), then you should repeat the previous steps to determine whether this would affect the path you have chosen.

The Model Browser has a quick option for comparing all the different RBF kernels.

1. After fitting the default RBF, select the RBF global model in the model tree.
2. Click the  (Build Models) toolbar icon.
3. Select the RBF Kernels icon in the Build Models dialog that appears and click OK.

One of each kernel is built as a selection of child nodes of the current RBF model.

Width Selection Algorithm: TrialWidths

How Many RBFs to Use