code: public NDArrayDoubles deepCopy() {
      int[] dimensions = new int[this.dimensions.length];
      System.arraycopy(this.dimensions, 0, dimensions, 0, this.dimensions.length);
      double[] values = new double[this.values.length];
      System.arraycopy(this.values, 0, values, 0, this.values.length);
      return new NDArrayDoubles(dimensions, values);
    }
docs: Copy this array.