Build caffe2 locally (not in /usr/lib) for compatibility with Python virtual environments (including Python 3)

build_caffe2_locally.sh

#!/bin/bash
set -ex
THISSCRIPTPATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
cd $THISSCRIPTPATH

echo "This script is for building Caffe2 locally (not in /usr/lib) on Ubuntu 16.04"
echo "Can be used for Python virtual environments"
echo "This assumes OpenCV is already installed: https://www.pyimagesearch.com/2016/10/24/ubuntu-16-04-how-to-install-opencv/"

my_python_version=$(python -c "import sys; print('.'.join(map(str, sys.version_info[:2])))")

#do_sudo_cmds=1

####################################################################
echo "installing dependencies..."

if [ -z ${do_sudo_cmds} ]; then echo "skipping sudo installs"; else
sudo apt-get update
sudo apt-get install -y --no-install-recommends \
	build-essential \
	git \
	libgoogle-glog-dev \
	libgtest-dev \
	libiomp-dev \
	libleveldb-dev \
	liblmdb-dev \
	libopenmpi-dev \
	libsnappy-dev \
	libprotobuf-dev \
	openmpi-bin \
	openmpi-doc \
	protobuf-compiler \
	libgflags-dev
exit 0
fi

pip install \
	future \
	numpy \
	scipy \
	cython \
	protobuf \
	pyyaml

#######################
# require latest cmake: https://github.com/caffe2/caffe2/issues/1810
pip install --upgrade cmake
####################################################################

CAFFE2PAT=$THISSCRIPTPATH/pytorch
# use in a virtual environment, so this can install to the virtual env's path
# if you are using docker, or don't mind,
# change this and remove the specified CMAKE_INSTALL_PREFIX below to let it install to system paths
caf2releasepath=$THISSCRIPTPATH

if ! [ -d pytorch/caffe2 ]; then
    git clone --recursive https://github.com/pytorch/pytorch.git
fi

# Caffe2 currently has trouble with Ubuntu 16.04's libeigen3-dev
# force it to use its own thirdparty/eigen by forcing "EIGEN3_FOUND=0"
sed -i -e 's/find_package(Eigen3)//g' $CAFFE2PAT/cmake/Dependencies.cmake

(cd pytorch && mkdir -p build && cd build/ && \
    cmake -D CMAKE_INSTALL_PREFIX=$caf2releasepath \
        -DEIGEN3_FOUND=0 \
        -DUSE_ROCKSDB=OFF \
        -DCUDA_ARCH_NAME=Manual \
        -DCUDA_ARCH_BIN="50 52 61" \
        -DCUDA_ARCH_PTX="50 52 61" \
        -D PYTHON_EXECUTABLE:FILEPATH=$(which python) \
        $(python $CAFFE2PAT/scripts/get_python_cmake_flags.py) .. \
    && make all -j8 && make install -j8)

# verify the installation
python -c "from caffe2.python import core"