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License

The source code is released under:

MIT License

Java Source Code

package com.alexkang.x3matrixcalculator.calculations;
/* ww w . java  2 s. co  m*/
public class Advanced {
  
  private static double[][] removeElement(double[][] list, int x) {
    if (x == 0) {
      double[][] listFinal = new double[list.length - 1][];
      System.arraycopy(list, 1, listFinal, 0, listFinal.length);
      return listFinal;
    }
    
    double[][] rest = new double[list.length - 1][];
    System.arraycopy(list, 1, rest, 0, rest.length);
    
    double[][] l = removeElement(rest, x-1);
    double[][] listFinal = new double[list.length - 1][];
    listFinal[0] = list[0];
    
    for (int i=0; i<l.length; i++) {
      listFinal[i+1] = l[i];
    }
    
    return listFinal;
  }
  
  private static double[] removeElement2(double[] list, int x) {
    if (x == 0) {
      double[] listFinal = new double[list.length - 1];
      System.arraycopy(list, 1, listFinal, 0, listFinal.length);
      return listFinal;
    }
    
    double[] rest = new double[list.length - 1];
    System.arraycopy(list, 1, rest, 0, rest.length);
    
    double[] l = removeElement2(rest, x-1);
    double[] listFinal = new double[list.length - 1];
    listFinal[0] = list[0];
    
    for (int i=0; i<l.length; i++) {
      listFinal[i+1] = l[i];
    }
    
    return listFinal;
  }
  
  private static double[][] slicer(double[][] matrix, int m, int n) {
    double[][] matrixM = removeElement(matrix, m);
    double[][] matrixFinal = new double[matrixM.length][];
    
    for (int i=0; i<matrixM.length; i++) {
      matrixFinal[i] = removeElement2(matrixM[i], n);
    }
    
    return matrixFinal;
  }
  
  private static double cofactor(double[][] matrix, int m, int n) {
    double[][] sub = slicer(matrix, m, n);
    return Math.pow(-1, m+n) * determinant(sub);
  }
  
  private static double[][] adjugate(double[][] matrix) {
    double[][] result = new double[matrix.length][matrix[0].length];
    
    for (int i=0; i<matrix.length; i++) {
      for (int j=0; j<matrix.length; j++) {
        result[i][j] = cofactor(matrix, i, j);
      }
    }
    
    return Basic.transpose(result);
  }

  public static double determinant(double[][] matrix) {
    if (matrix.length == 2) {
      return (matrix[0][0]*matrix[1][1]) - 
          (matrix[0][1]*matrix[1][0]);
    }
    double total = 0.0;
    for (int i=0; i<matrix.length; i++) {
      total += Math.pow(-1, i) * matrix[0][i] * determinant(slicer(matrix, 0, i));
    }
    return total;
  }
  
  static public double[][] inverse(double[][] matrix) {
    try {
      double[][] inv = adjugate(matrix);
      double oneOverDet = 1 / determinant(matrix);
      
      if (matrix.length == 2) {
        inv[0][0] = oneOverDet * matrix[1][1];
        inv[0][1] = -oneOverDet * matrix[0][1];
        inv[1][0] = -oneOverDet * matrix[1][0];
        inv[1][1] = oneOverDet * matrix[0][0];
        
        for (int i=0; i<matrix.length; i++) {
          for (int j=0; j<matrix.length; j++) {
            inv[i][j] = Math.round(inv[i][j] * 1000.0) / 1000.0;
          }
        }
        
        return inv;
      }
      
      for (int i=0; i<matrix.length; i++) {
        for (int j=0; j<matrix[0].length; j++) {
          inv[i][j] = inv[i][j] * oneOverDet;
        }
      }
      
      for (int i=0; i<matrix.length; i++) {
        for (int j=0; j<matrix.length; j++) {
          inv[i][j] = Math.round(inv[i][j] * 1000.0) / 1000.0;
        }
      }
      
      return inv;
    }
    
    catch (Exception e) {
      double[][] errorMatrix = new double[matrix.length][matrix.length];
      for (int i=0; i<matrix.length; i++) {
        for (int j=0; j<matrix.length; j++) {
          errorMatrix[i][j] = 0;
        }
      }
      return errorMatrix;
    }
  }
}

Java Source Code List

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