gfortran-9 installed, but getting "no Fortran compiler found" error (Ubuntu Server 18.04)

Question

I've just installed gfortran-9 on Ubuntu Server 18.04 as follows:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update
sudo apt install gfortran-9

I've been able to confirm that gfortran-9 is working correctly by compiling and running a simple 'Hello World' program.

I'm now trying to install PyPROSAIL as follows:

sudo -H pip3 install pyprosail

... but I'm receiving the following error:

error: extension 'PyPROSAIL._prosail_model' has Fortran sources but no Fortran compiler found

gfortran-9 --version shows me the following:

GNU Fortran (Ubuntu 9.2.1-17ubuntu1~18.04.1) 9.2.1 20191102
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

whereis gfortran-9 shows me the following:

gfortran-9: /usr/bin/gfortran-9 /usr/share/man/man1/gfortran-9.1.gz

Why is gfortran-9 apparently not being found? Do I need to manually set a path to gfortran-9 somewhere?

Answer 1

In case anyone else is having the same issue, I was able to solve this by installing a different Fortran compiler - gfortran:

sudo apt-get install gfortran