Entropy In Java

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import weka.core.matrix.Matrix;   public class EntropyCalculator {       public static double getEntropy(Matrix matrix) {         double entropy = 0;         double[] sumOfRows = getSumOfRows(matrix);         double sumOfMatrix = 0;         for (int i = 0; i < sumOfRows.length; i++) {             sumOfMatrix += sumOfRows[i];         }         for (int i = 0; i < matrix.getRowDimension(); i++) {             double r = sumOfRows[i] / sumOfMatrix;             double sum = 0;             for (int j = 0; j < matrix.getColumnDimension(); j++) {                 double x = matrix.get(i, j) / sumOfRows[i];                 if (x == 0) {                     sum += 0;                 } else {                     sum += x * (Math.log10(x) / Math.log10(2));                 }             }             entropy += (r * sum) * (-1);         }         return entropy;     }       private static double[] getSumOfRows(Matrix matrix) {         double[] result = new double[matrix.getRowDimension()];         for (int i = 0; i < matrix.getRowDimension(); i++) {             for (int j = 0; j < matrix.getColumnDimension(); j++) {                 result[i] += matrix.get(i, j);             }         }         return result;     }       private static double[] getSumOfColumns(Matrix matrix) {         double[] result = new double[matrix.getColumnDimension()];         for (int i = 0; i < matrix.getRowDimension(); i++) {             for (int j = 0; j < matrix.getColumnDimension(); j++) {                 result[j] += matrix.get(i, j);             }         }         return result;     }       public static void main(String[] args) {         double[][] array = new double[3][3];         array[0][0] = 3;         array[0][1] = 4;         array[0][2] = 12;         array[1][0] = 8;         array[1][1] = 3;         array[1][2] = 12;         array[2][0] = 12;         array[2][1] = 12;         array[2][2] = 0;         System.out.println(getEntropy(new Matrix(array)));     }