G4 ifarm singularity GPU containers

[cissieAB]

The process of setting up g4 inside ifarm singularity containers is taken down at

https://github.com/nathanwbrei/phasm/blob/main/docs/farm_guide_singularity.md#4-run-geant4-within-singularity-container

Basically, we upload a container (without G4) to
/scigroup/cvmfs/epsci/singularity/images​,
of which is synchronized to cvmfs automatically. Then we launch this container through the cvmfs address
/cvmfs/oasis.opensciencegrid.org/jlab/epsci/singularity/images​

Inside the container, we init the G4 environment through spack, and then we are able to visit the cvmfs pre-installed software at
$SPACK_ROOT/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/*​

The only concern about the G4 B4d example for me now is that ifarm slurm does not support X11 forwarding. So we are not able to see a window coming out after we launch B4d and the tracks of the particles on the GPU nodes, as we usually do on the login nodes. But if we do not need runtime graphics, this is not a big problem.

Specifically, the G4 stuff is at
$SPACK_ROOT/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/geant4-11.1.0-px46pszk3frzg74fdbsqktipkohbyq3u​

There is also an env setup script. If I run this script, the G4 stuff goes to my $PATH and $LD_LIBRARY_PATH.
I guess EIC-shell is using a similar mechanism.

. $SPACK_ROOT/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/geant4-11.1.0-px46pszk3frzg74fdbsqktipkohbyq3u/bin/geant4.sh 

Singularity> echo $PATH

/cvmfs/oasis.opensciencegrid.org/jlab/epsci/ubuntu/22.04/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/geant4-11.1.0-px46pszk3frzg74fdbsqktipkohbyq3u/bin:/cvmfs/oasis.opensciencegrid.org/jlab/epsci/ubuntu/22.04/var/spack/environments/phasm/.spack-env/view/bin:/cvmfs/oasis.opensciencegrid.org/jlab/epsci/ubuntu/22.04/bin:/opt/conda/bin:/deps/JANA2/install/bin:/usr/local/nvidia/bin:/usr/local/cuda/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

Singularity> echo $LD_LIBRARY_PATH 

/cvmfs/oasis.opensciencegrid.org/jlab/epsci/ubuntu/22.04/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/geant4-11.1.0-px46pszk3frzg74fdbsqktipkohbyq3u/lib:/deps/libtorch/lib:/deps/libtorch/lib:/usr/lib/x86_64-linux-gnu:/usr/local/cuda/lib64:/usr/local/cuda/lib:/usr/local/nvidia/lib:/usr/local/nvidia/lib64:/.singularity.d/libs:/cvmfs/oasis.opensciencegrid.org/jlab/epsci/ubuntu/22.04/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/clhep-2.4.6.0-keceb3wlevwti6hhlxd3rnvrwolqwznm/lib:/cvmfs/oasis.opensciencegrid.org/jlab/epsci/ubuntu/22.04/opt/spack/linux-ubuntu22.04-x86_64/gcc-11.3.0/xerces-c-3.2.3-72hxrmfwdragrcclabqgy64tikxy4a65/lib