Super slow when running demos

Hello,

I am using a 1080Ti graphic card. The demos are running super super slow.
It even took a long time to show the GUI visualization window.
I followed the installazation guide from github using : python3 -m pip install taichi

Here is of configuration of my PC :
Ubuntu 18.04
CUDA 10.1
NVIDIA 1080Ti
demos running : python3 diffmpm.py
from https://github.com/yuanming-hu/difftaichi
the other demos are almost the same.

I am not sure what happened. Could you help me on this?
Thank you very much.