Compiler choice in 1.9.3?

[benjamin-cash]

How do I specify that I only want gcc to be used for c and c++ in 1.9.3? @climbfuji showed me how to do it for 2.1, but it seems like that procedure doesn't work on the earlier versions.

[climbfuji]

You'll need to copy the setup from a tier-1 site, for example Atlantis: https://github.com/JCSDA/spack-stack/tree/1.9.3/configs/sites/tier1/atlantis - take a look at packages_gcc.yaml and compilers.yaml.

I believe that for 1.9.3, the --compiler argument for spack stack create env was simply --compiler=gcc, i.e. no version attached.

See also https://spack-stack.readthedocs.io/en/1.9.3/index.html

Side note: With spack-stack-2.0.0, all documentation moved to the Wiki.

[benjamin-cash]

Hi Dom - One of the failure modes I hit seemed to be gfortran was being used to compile some of the fortran code. I know when we set up 2.1 we were able to explicitly set gcc for use only with c and c++ code and was hoping for something along those lines.

[climbfuji]

I think there were one or maybe two packages that were indeed compiled with GCC (scotch?), including gfortran. That worked "by chance". The update to Spack v1 and spack-stack v2 solved this problem.

[benjamin-cash]

Unfortunately it seems like the weather model is still on 1.9.3 and does not work reliably with 2+. I can build and run using a containerized version of 1.9.3, but there is a random failure mode that might be related to the container that I was hoping to nail down.

[climbfuji]

I am going to be quite honest here. I am having a hard time justifying to myself (and the ones who pay me) to spend time and efforts on supporting an old release of spack-stack without any clear benefit. 1.9.3 is a dying horse, and the ufs-weather-model is made 2.1.0-compliant as we speak (see Gillian Petro's PRs in the ufs-weather-model).

I am fully supportive of helping with 2.1 / develop setups on tier 2 platforms because this will translate to better instructions for users setting up their own environments, which ultimately benefits all of spack-stack.