如何计算邻接矩阵平方的高阶导数？

Question

我想在Pytorch中计算高阶导数，但结果是nan。

 You will also need to install
 On Unix
 python (v2.7 recommended, v3.x.x is not supported)
 make
 A proper C/C++ compiler toolchain, like GCC

输出grad2全部为nan。你能告诉我如何得到正确的结果吗？