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As some MPI libraries work better on some hardware than others, and some software works best with some MPI library, the selection of the library used must be done in user level, on a session specific basis. Also, people doing high performance computing may want to use more efficient compilers than the default one in Fedora (gcc), so one must be able to have many versions of the MPI compiler each compiled with a different compiler installed at the same time. This must be taken into account when writing spec files.
Packaging of MPI compilers
The files of MPI compilers MUST be installed in the following directories:
|File type |Placement
|Binaries |`+%{_libdir}/%{name}/bin+`
|Libraries |`+%{_libdir}/%{name}/lib+`
|[[PackagingDrafts/Fortran |Fortran modules]] |`+%{_fmoddir}/%{name}+`
|[[Packaging/Python |Python modules]] |`+%{python2_sitearch}/%{name}+`
|Config files |`+%{_sysconfdir}/%{name}-%{_arch}+`
As include files and manual pages are bound to overlap between different MPI implementations, they MUST also placed outside normal directories. It is possible that some man pages or include files (either those of the MPI compiler itself or of some MPI software installed in the compiler's directory) are architecture specific (e.g. a definition on a 32-bit arch differs from that on a 64-bit arch), the directories that MUST be used are as follows:
|File type |Placement
|Man pages |`+%{_mandir}/%{name}-%{_arch}+`
|Include files |`+%{_includedir}/%{name}-%{_arch}+`
Architecture independent parts (except headers which go into `+-devel+`) MUST be placed in a `+-common+` subpackage that is `+BuildArch: noarch+`.
The runtime of MPI compilers (mpirun, the libraries, the manuals etc) MUST be packaged into %\{name}, and the development headers and libraries into %\{name}-devel.
As the compiler is installed outside `+PATH+`, one needs to load the relevant variables before being able to use the compiler or run MPI programs. This is done using xref:EnvironmentModules.adoc[environment modules].
The module file MUST be installed under `+%{_sysconfdir}/modulefiles/mpi+`. This allows as user with only one mpi implementation installed to load the module with:
module load mpi
The module file MUST have the line:
conflict mpi
to prevent concurrent loading of multiple mpi modules.
The module file MUST prepend `+$MPI_BIN+` into the user's `+PATH+` and prepend `+$MPI_LIB+` to `+LD_LIBRARY_PATH+`. The module file MUST also set some helper variables (primarily for use in spec files):
|Variable |Value |Explanation
|`+MPI_BIN+` |`+%{_libdir}/%{name}/bin+` |Binaries compiled against the MPI stack
|`+MPI_SYSCONFIG+` |`+%{_sysconfdir}/%{name}-%{_arch}+` |MPI stack specific configuration files
|`+MPI_FORTRAN_MOD_DIR+` |`+%{_fmoddir}/%{name}+` |MPI stack specific Fortran module directory
|`+MPI_INCLUDE+` |`+%{_includedir}/%{name}-%{_arch}+` |MPI stack specific headers
|`+MPI_LIB+` |`+%{_libdir}/%{name}/lib+` |Libraries compiled against the MPI stack
|`+MPI_MAN+` |`+%{_mandir}/%{name}-%{_arch}+` |MPI stack specific man pages
|`+MPI_PYTHON2_SITEARCH+` |`+%{python2_sitearch}/%{name}+` |MPI stack specific Python 2 modules
|`+MPI_PYTHON3_SITEARCH+` |`+%{python3_sitearch}/%{name}+` |MPI stack specific Python 3 modules
|`+MPI_COMPILER+` |`+%{name}-%{_arch}+` |Name of compiler package, for use in e.g. spec files
|`+MPI_SUFFIX+` |`+_%{name}+` |The suffix used for programs compiled against the MPI stack
As these directories may be used by software using the MPI stack, the MPI runtime package MUST own all of them.
MUST: By default, NO files are placed in `+/etc/ld.so.conf.d+`. If the packager wishes to provide alternatives support, it MUST be placed in a subpackage along with the ld.so.conf.d file so that alternatives support does not need to be installed if not wished for.
MUST: If the maintainer wishes for the environment module to load automatically by use of a scriptlet in /etc/profile.d or by some other mechanism, this MUST be done in a subpackage.
MUST: The MPI compiler package MUST provide an RPM macro that makes loading and unloading the support easy in spec files, e.g. by placing the following in `+/etc/rpm/macros.openmpi+`