Initializes the necessary data members, scans the main Arff file and then
instantiates the data members FeatureNames,
NumFlags, CategoryNames and RawDataset.
Helper class for jncc, which accomplishes the following tasks:
reads the temporary file where NBC and NCC predictions are stored;
computes performances indexes; produces the output file, which reports both
the discretization log (i.e., whether some numerical feats have been discretized into a single bin)
and the classifiers results.