/** uses the filter */
protected static void useFilter(Instances data) throws Exception {
System.out.println("\n2. Filter");
weka.filters.supervised.attribute.AttributeSelection filter =
new weka.filters.supervised.attribute.AttributeSelection();
CfsSubsetEval eval = new CfsSubsetEval();
GreedyStepwise search = new GreedyStepwise();
search.setSearchBackwards(true);
filter.setEvaluator(eval);
filter.setSearch(search);
filter.setInputFormat(data);
Instances newData = Filter.useFilter(data, filter);
System.out.println(newData);
}
/**
* selects a given number of features by info gain eval
*
* @param number the number of features to select
* @throws Exception
*/
public void selectFeatures(int number) throws Exception {
weka.filters.supervised.attribute.AttributeSelection filter =
new weka.filters.supervised.attribute.AttributeSelection();
InfoGainAttributeEval eval = new InfoGainAttributeEval();
Ranker search = new Ranker();
search.setNumToSelect(number);
filter.setEvaluator(eval);
filter.setSearch(search);
filter.setInputFormat(_train);
Instances newData = Filter.useFilter(_train, filter);
Instances newData_test = Filter.useFilter(_test, filter);
_train = newData;
_test = newData_test;
}