Spack is a package manager which is very useful to install scientific software.

Preparing a Linux system

We will install the gcc and gfortran compilers from the system package manager. Dont install anything else since they will be installed using Spack. There are some instructions for OpenSUSE and Debian. Since Spack installs its own MPI library, it is best to uninstall any MPI you may have installed from your system package manager, since having multiple MPI around can cause problems.

Preparing a Mac system

Install Spack

We will install Spack into SPACK_ROOT directory.

export SPACK_ROOT=/path/to/spack

Now get Spack

git clone $SPACK_ROOT

You can add following lines to your .bashrc or .profile file

export SPACK_ROOT=/path/to/spack
. ${SPACK_ROOT}/share/spack/

Here are some useful Spack commands

spack list intel          -- search package names containing intel
spack info gcc            -- show information for package gcc
spack find                -- shows installed packages
spack compilers           -- show available compilers
spack location -i openmpi -- show location of openmpi

Setup compilers by running

spack compiler find

which creates the file compilers.yaml inside $HOME/.spack/darwin directory. Edit it if needed.

On Mac, use clang from Apple command line tools and gfortran from Homebrew. My file $HOME/.spack/darwin/compilers.yaml looks like this

- compiler:
    environment: {}
    extra_rpaths: []
    flags: {}
    modules: []
    operating_system: highsierra
      cc: /usr/bin/clang
      cxx: /usr/bin/clang++
      f77: /usr/local/bin/gfortran
      fc: /usr/local/bin/gfortran
    spec: clang@9.0.0-apple
    target: x86_64

On Linux, use the gcc and gfortran from your system.

Set some package variants in $HOME/.spack/darwin/packages.yaml file like this

      variants: +fortran +cxx +hl
      variants: +mumps +suite-sparse
      variants: +fortran
      variants: +rol
         mpi: [mpich]

By default, Spack uses openmpi but you can select mpich as above. If you want to use openmpi, then change above line from mpich to openmpi or just dont specify the mpi provider.

Install softwares

I install deal.II and its dependencies which provides all the softwares that I need for my work. Since I like to compile deal.II myself, I will install only dependencies. But first check that all variants you need are correct by running

spack spec dealii
spack spec -I dealii # -I shows already installed dependents

If this is ok, then we install

spack install -j4 --fail-fast --only dependencies dealii

The flag -j4 means that four processes will be used while compiling; increase this if you have more cores on your computer. If you primarily use Petsc and Metis, and dont need other stuff, then do

spack spec petsc
spack install -j4 --fail-fast petsc

Now create a Spack view by running the script which will install symlinks into SPACK_VIEW directory.

export SPACK_VIEW=/path/to/spack/view # Add to .bashrc or .profile file
sh /path/to/ /path/to/spack/view/dir

If the SPACK_VIEW directory is in not in your home directory, then set ownership, e.g.,

sudo mkdir $SPACK_VIEW
sudo chown praveen:users $SPACK_VIEW

and then run the script. This is useful on a Linux computer where I want to install the software for all users.

Here is a sample script which you can edit for your needs. If you use mpich, then change openmpi to mpich in the script file.

You can set some variables in your .bashrc or .profile file


which can be used in your makefiles for compiling your applications.


When I want to upgrade, I usually reinstall everything from scratch.

git pull

Update your compilers.yaml and packages.yaml files if needed. Verify that you get all package variants that you need. Then continue

spack uninstall --all
spack install -j4 --fail-fast --only dependencies dealii

Now we create a new spack view

sh /path/to/

Finding info on an installed package

$ spack find -l petsc
==> 1 installed package
-- linux-opensuse_tumbleweed20200511-broadwell / gcc@9.3.1 ------
c67eysz petsc@3.13.1

Find more about installed petsc

spack spec /c67eysz