How to tell if I have the prerequisites for building?

CMake

Both OpenMC and NekRS use CMake for building. To check if you have CMake, you should be able to print a version number:

cmake --version

which will print something like

cmake version 3.23.2

CMake suite maintained and supported by Kitware (kitware.com/cmake).

If cmake --version does not print anything, you need to obtain CMake. If you're on a cluster, you can do a command like module spider cmake to search for CMake modules and then load one.

If you are on a personal computer, download CMake and then make sure that the CMake binary is on your PATH.

MPI

Both NekRS and OpenMC use MPI parallelism. To check if you have MPI, you should be able to print the versions of various MPI compiler wrappers on your system. For the C++ wrapper:

mpicxx --version

should print something like:

g++ (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
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

For the C wrapper:

mpicc --version

should print something like:

gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
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.

And for the Fortran wrapper:

mpif90 --version

should print something like:

GNU Fortran (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
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.

If any of the above does not print something, you need to get MPI wrappers. If you are on a cluster, you can try commands like module spider mpich for the MPICH implementation, module spider openmpi for the OpenMPI implementation, module spider intel for the Intel implementation, etc. Then, load the module you want.

If you are on a personal computer, try downloading MPICH, download OpenMPI, or download Intel MPI.

Then, it's a good idea to explicitly set in your ~/.bashrc that you want to use the MPI compiler wrappers:

export CC=mpicc
export CXX=mpicxx
export FC=mpif90

GNU Fortran compilers

NekRS currently requires the GNU Fortran compilers. To check which Fortran compilers you are using, try:

mpif90 --version

which will print something like

GNU Fortran (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
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.

The GNU Fortran part indicates that this is a GNU Fortran compiler. You will want to be sure that you have set export FC=mpif90 in order to instruct Cardinal to use this specific compiler.

If NekRS still complains Cannot find a supporter compiler! even though you know you are using gfortran, try:

export MPICH_FC=gfortran

HDF5

OpenMC requires HDF5 for cross section data and writing output files. If you are using MOOSE's conda environment, please set:

export HDF5_ROOT=$CONDA_PREFIX

If you are instead building PETSc and libMesh via the scripts, MOOSE will automatically download it for you when building PETSc. If you don't want to use this auto-download and are on a cluster, trying module spider hdf5 and then load a module.

If you are on a personal computer, try:

cd /
find . -name "libhdf5.*"

which will print out where you have the HDF5 libraries. Then, you should set HDF5_ROOT to the top-level directory that contains the include and lib HDF5 directories.