question: protected double entropy ( double [ ] [ ] dataZs , double [ ] [ ] dataWs ) { double entropy = 0.0 ; int numInstances = dataZs . length ; for ( int j = 0 ; j < m_numClasses ; j ++ ) { double m = 0.0 ; double sum = 0.0 ; for ( int i = 0 ; i < numInstances ; i ++ ) { m += dataZs [ i ] [ j ] * dataWs [ i ] [ j ] ; sum += dataWs [ i ] [ j ] ; } m /= sum ; for ( int i = 0 ; i < numInstances ; i ++ ) { entropy += dataWs [ i ] [ j ] * Math . pow ( dataZs [ i ] [ j ] - m , 2 ) ; } } return entropy ; }
target:  Helper function to compute entropy from Z/W values.