Build Faiss with MKL on Ubuntu

Faiss’ documentation on installing from source is not so helpful when it comes to using MKL. With some effort on searching the web, I got it to work finally

# install MKL
# https://www.intel.com/content/www/us/en/developer/tools/oneapi/onemkl-download.html?operatingsystem=linux&distributions=aptpackagemanager
wget -O- https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB \
| gpg --dearmor | sudo tee /usr/share/keyrings/oneapi-archive-keyring.gpg > /dev/null
echo "deb [signed-by=/usr/share/keyrings/oneapi-archive-keyring.gpg] https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
sudo apt update
sudo apt install intel-oneapi-mkl

# set MKL variables
source /opt/intel/oneapi/setvars.sh

# clone faiss
git clone https://github.com/facebookresearch/faiss.git

# build
cd faiss
cmake -DBUILD_SHARED_LIBS=ON -DFAISS_ENABLE_GPU=OFF -DFAISS_ENABLE_PYTHON=OFF -DBUILD_TESTING=OFF -DFAISS_ENABLE_C_API=ON -Bbuild
make -Cbuild -j

Reference: https://stackoverflow.com/questions/58666921/how-to-set-mkl-on-linux-with-cmake