Installing Metis for precompiled OpenFOAM-v2112

For OpenFOAM-v2112 installed using apt, here I share a quick guide to install metis.
First, obtain the metis-5.1 source code and compile it.

$ make config
$ make
$ sudo make install 

The last commad creates libmetis.a in /usr/local/lib.

Secondly, compile the metis interface in OpenFOAM

$ cd $FOAM_SRC/parallel/decompose
$ sudo chmod -R 777 .
$ ./Allwmake

Done!