Picongpu: OpenMPI requires both C and Fortran compilers during spack install.

[berceanu]

Followind the spack install instructions on an Ubuntu 18.04 box, the above message appears while building openmpi. It can be fixed by setting

   f77: /usr/bin/gfortran-7
   fc: /usr/bin/gfortran-7

in compilers.yaml or running

spack compiler find

provided of course, gfortran is installed.

[ax3l]

Yes, that's currently a limitation of the OpenMPI package in Spack itself. Thank you for documenting this here! :sparkles:

[berceanu]

I'm not sure how important it is for building openmpi that gcc and gfortran should be the same version. If they should be, then the above fix will often fail, as the system gfortran might be a different version than the spack gcc package. So should we add gfortran to the spack dependency list instead?

[ax3l]

I thought that the current workflow to spack install gcc and then spack load gcc + spack compiler find does that. Did we miss it? By default, the spack gcc package installs the c, c++ and fortran languages.

[berceanu]

You're absolutely right, gfortran is installed along with gcc.

[ax3l]

Ok, so this was probably just a big mixed up while you debugged the other issues?

[berceanu]

Yes, looks like everything is working now :)

[ax3l]

Cool! Just have this corner-case concern left: https://github.com/ComputationalRadiationPhysics/picongpu/pull/2773#issuecomment-433327962

[hightower8083]

By the way, its, probably off-topic, but about a week they have released openmpi.4.0.0. While spack takes it by default for the given requirement [email protected]:3.0, building it with gcc5.5.0 crashes with a msg like,

Error: Line truncated at (1) [-Werror=line-truncation]
mpi-ext-module.F90:29:6:

I had to replace requirement [email protected]:3.0 with [email protected] to complete the installation

[ax3l]

Thanks for the note!
I now updated the recipe to explicitly build on OpenMPI between 1.8 and 3.99: https://github.com/ComputationalRadiationPhysics/spack-repo/commit/69327543e1892011dbbb8485a213a7c1433fa9ac

[ax3l]

@hightower8083 can you please report the GCC 5.5 build issue that you get when running

spack install -v [email protected] %[email protected]

upstream in https://github.com/open-mpi/ompi ? I think it's not reported yet.

[hightower8083]

sure -- i'll check it again and will tell em