It is suspected that this error comes from the multiple library confilcts which have libiomp5.dll files.
One solution is to delete libiomp5md.dll (and other libiomp5 related files)
in anaconda3/Library/bin . (anaconda3 is located in hidden "ProgramData" folder.)
It is not clear whether this is the best solution, but it works.
(Update) The above symptom first appeared while using PyTorch , Matplotlib, and Scipy.
However, after above procedure,
there are many occasions that the kernel stops and restart. Python became very unstable.
To avoid this problem, it may be better to use separate environment when installing pytorch.
