code: public static double[][] toDouble(int[][] array) {
          double[][] n = new double[array.length][array[0].length];
          for (int i = 0; i < array.length; i++) {
              for (int j = 0; j < array[0].length; j++) {
                  n[i][j] = (double) array[i][j];
              }
          }
          return n;
      }
docs: 2-D Integer array to double array.
  
  @param array Integer array.
  @return Double array.