I got some errors from mpi, mpich in UBUNTU 18.04, how can I remove all previous version MPI correctly.
||/ Name Version Architecture Description
+++-==============-============-============-=================================
un libblacs-mpi-d <none> <none> (no description available)
ii libboost-mpi-d 1.65.1.0ubun amd64 C++ interface to the Message Pass
ii libboost-mpi-p 1.65.1.0ubun amd64 C++ interface to the Message Pass
un libboost-mpi-p <none> <none> (no description available)
un libboost-mpi-p <none> <none> (no description available)
ii libboost-mpi-p 1.65.1+dfsg- amd64 C++ interface to the Message Pass
ii libboost-mpi-p 1.65.1+dfsg- amd64 C++ interface to the Message Pass
un libboost-mpi1. <none> <none> (no description available)
ii libboost-mpi1. 1.65.1+dfsg- amd64 C++ interface to the Message Pass
ii libboost-mpi1. 1.65.1+dfsg- amd64 C++ interface to the Message Pass
ii mpi-default-bi 1.10 amd64 Standard MPI runtime programs (me
ii mpi-default-de 1.10 amd64 Standard MPI development files (m
ii mpich 3.3~a2-4 amd64 Implementation of the MPI Message
ii python-mpi4py 2.0.0-3 amd64 bindings of the Message Passing I
un valgrind-mpi <none> <none> (no description available)
Thanks a lot in advance!