How to rebuild lib/knn for solving the problem undefined symbol: _Py_Dealloc

[Shoichi-Hasegawa0628]

Hello,
When ./experiments/scripts/train_ycb.sh was executed, I encountered this problem.
ImportError: /root/HSR/catkin_ws/src/DenseFusion/lib/knn/knn_pytorch/_knn_pytorch.so: undefined symbol: _Py_Dealloc

I read this same Issue.
#2 (comment)

However,
I couldn't understand how to solve it.

The _knn_pytorch.so in this repo is built with python3. If you want to use python2, you need to rebuild the lib/knn (with PyTorch-0.4.1).
For your case, please make sure your CFFI is correctly installed. More information https://cffi.readthedocs.io/en/latest/installation.html#linux-and-os-x-ucs2-versus-ucs4.

Does that mean rebuilding lib / knn after doing pip install cffi?

Also, do you know which folder the code used for rebuilding should be and what command should be executed?
Thank you.