Last night, I built from source as indicated in https://github.com/pytorch/pytorch#from-source 5
export CMAKE_PREFIX_PATH="$(dirname $(which conda))/…/" # [anaconda root directory]
Install basic dependencies
conda install numpy pyyaml mkl mkl-include setuptools cmake cffi typing
git clone --recursive https://github.com/pytorch/pytorch 7
cd pytorch
python setup.py install   (Had NO_CUDA=1 and FULL_CAFFE2=1) environmental variables.
Now,
Good News is when I go into the bin directory invoke the python from there and in the REPL if I import torch, it works. (This is python 2.7,btw)
print torch.version gives 1.0.0.a0+aec9fdf
But ‘from caffe2.python import core’  says ‘No Module named google.protobuf.internal’
Questions:

How do I get python3 to work? The torch subdirectory gets  installed under ./lib/python2.7/site-packages. (Under python3, import torch does not work.)
I dont see FULL_CAFFE2 variable getting used in setup.py
For protobuf problem for caffe2, what should I additionally install?
Thanks for your help!