Applying CFS to Machine Learning
Problems
Figure 1 shows the stages of the CFS algorithm and
how it is used in conjunction with a machine learning
algorithm. A copy of the training data is ¯rst discretized
using the method of Fayyad and Irani (1993),
then passed to CFS. CFS calculates feature-class and
feature-feature correlations using symmetrical uncertainty
and then searches the feature subset space. The
subset with the highest merit (as measured by Equation
1) found during the search is used to reduce the
dimensionality of both the original training data and
the testing data. Both reduced datasets may then be
passed to a machine learning algorithm for training and
testing.