public BigDecimal calculateEntropy(
Map<Integer, AttributeValue> attributeValues, boolean withVariance) throws MLException {
if (!withVariance) {
return calculateEntropy(attributeValues);
} else {
BigDecimal attributeEntropyresult = new BigDecimal(0);
for (AttributeValue attributeValue : attributeValues.values()) {
int attributeValueCount = attributeValue.getAttributeValueCount();
BigDecimal innerVarianceResult = new BigDecimal(1);
for (Integer corrospondingClassifiedCount :
attributeValue.getClassifiedCountMap().values()) {
BigDecimal fraction =
BigDecimal.valueOf(corrospondingClassifiedCount)
.divide(new BigDecimal(attributeValueCount), globalMathContext);
innerVarianceResult.multiply(fraction, globalMathContext);
}
attributeValue.setEntropy(innerVarianceResult);
BigDecimal attributeGlobalFraction =
BigDecimal.valueOf(attributeValueCount)
.divide(new BigDecimal(size()), globalMathContext);
attributeEntropyresult =
attributeEntropyresult.add(attributeGlobalFraction.multiply(innerVarianceResult));
}
return attributeEntropyresult;
}
}
public BigDecimal calculateEntropy(Map<Integer, AttributeValue> attributeValues)
throws MLException {
BigDecimal attributeEntropyresult = new BigDecimal(0);
for (AttributeValue attributeValue : attributeValues.values()) {
int attributeCount = attributeValue.getAttributeValueCount();
BigDecimal innerResult = new BigDecimal(0);
for (Integer corrospondingClassifiedCount : attributeValue.getClassifiedCountMap().values()) {
BigDecimal fraction =
BigDecimal.valueOf(corrospondingClassifiedCount)
.divide(new BigDecimal(attributeCount), globalMathContext);
BigDecimal logFraction =
BigDecimal.valueOf(Math.log(fraction.doubleValue()))
.divide(new BigDecimal(Math.log(2)), globalMathContext);
innerResult = innerResult.add(fraction.multiply(logFraction, globalMathContext));
}
innerResult = innerResult.negate();
attributeValue.setEntropy(innerResult);
BigDecimal attributeGlobalFraction =
BigDecimal.valueOf(attributeValue.getAttributeValueCount())
.divide(new BigDecimal(size()), globalMathContext);
attributeEntropyresult =
attributeEntropyresult.add(attributeGlobalFraction.multiply(innerResult));
}
return attributeEntropyresult;
}
