Construction of a rejecting classifier
WR = REJECTC(A,W,FRAC,TYPE)
a = gendatb
This command extends an arbitrary classifier with a reject option. If WR is used for classifying a dataset B, then D = B*WR has C+1 columns ('features'), one for every class in A and an additional one that takes care of the rejection: a NaN for numeric labels (classnames in A) or en empty string for string labels. NOTE: Objects that are rejected are not counted as an error in TESTC. The classification error estimated by TESTC just considers the total number of objects for wich B*WR*LABELD has a correct classname and neglects all others. So by rejection the error estimate by TESTC may increase, decrease or stay equal.