SDCASCADE Construct classifier cascade or hierarchical classifier

    PP=SDCASCADE(STAGE1,THROUGH,STAGE2,...)

 INPUT
    STAGE      stage classifier (pipeline object returning decisions)
    THROUGH    decision (string) which is passed to the next stage

 OUTPUT
    PP         pipeline object

 DESCRIPTION
 SDCASCADE implements a cascade or hierarchy of classifiers. Each stage
 is a pipeline returning decisions. The STAGE1 pipeline is
 executed on all input examples. Only the samples labeled as THROUGH
 are passed on to the STAGE2.

 READ MORE
 http://perclass.com/doc/guide/classifiers.html#hierarchy

sdcascade is referenced in examples:

• kb22: Note on decision tree performance and speed
• kb11: Hierarchical classifier: How to build detector-classifier cascade?