code: public static double determinant3x3(
      final double r0c0,
      final double r0c1,
      final double r0c2,
      final double r1c0,
      final double r1c1,
      final double r1c2,
      final double r2c0,
      final double r2c1,
      final double r2c2)
    {
      double sum = 0.0;
      sum += r0c0 * ((r1c1 * r2c2) - (r1c2 * r2c1));
      sum -= r0c1 * ((r1c0 * r2c2) - (r1c2 * r2c0));
      sum += r0c2 * ((r1c0 * r2c1) - (r1c1 * r2c0));
      return sum;
    }
docs: Calculate the determinant of the given 3x3 matrix values.
  
  @param r0c0 The value at row 0 column 0
  @param r0c1 The value at row 0 column 1
  @param r0c2 The value at row 0 column 2
  @param r1c0 The value at row 1 column 0
  @param r1c1 The value at row 1 column 1
  @param r1c2 The value at row 1 column 2
  @param r2c0 The value at row 2 column 0
  @param r2c1 The value at row 2 column 1
  @param r2c2 The value at row 2 column 2
  
  @return The determinant