code: int[][] fix() {
          int[][] m = new int[nRows][mCols];
          for (int i = 0; i < nRows; i++)
              System.arraycopy(data, (i * mCols), m[i], 0, mCols);
          return m;
      }
docs: Create a fixed-size 2D array of the matrix (useful for debug).
  
  @return a fixed version of the matrix