private double informationGain(String attribute, Map<String, String> specifiedAttributes) {
double sum = entropy(specifiedAttributes);
double examplesCount = records.count(specifiedAttributes);
if (examplesCount == 0) return sum;
Map<String, Set<String>> decisions = records.extractDecisions();
for (String decision : decisions.get(attribute)) {
double entropyPart = entropy(attribute, decision, specifiedAttributes);
// logger.info("entropyPart is --> {}.", entropyPart);
double decisionCount = records.countDecisions(attribute, decision);
sum += -(decisionCount / examplesCount) * entropyPart;
}
return sum;
}
