(Uncommon) Build Problems

Here's a list of not so common problems that you might encounter when building WHIZARD that didn't make it into the INSTALL file​.

Compiler and Shared Library search PATHs

If you are using gfortran, you will have installed a version >= 4.5, which is not yet the one that came with your Linux distribution. This is not very hard to do and causes absolutely no harm. Nevertheless please make sure that the environment variables

   PATH=<path to the gfortran-4.5 binary>:$PATH
   LD_LIBRARY_PATH=<path to the gfortran-4.5-libraries>

are set correctly. You will get strange runtime errors, if the new compiler links WHIZARD to the old compiler's runtime libraries.

Parallel Make and Slow Filesystems

The current version of O'Mega uses intermediate files in .../var/cache/ to store precomputed vertex tables in order to significantly increase the startup speed for complicated BSM models with many new particles and vertices. These files are generated as needed and require no user intervention.

Unfortunately, if several copies of O'Mega for the same model are running simultaneously and for the very first time, they might encounter an incomplete version of the vertex table. In practice, this almost never a problem, but if you run make check with the -j option (parallel execution) on slow networked file systems, a few checks might fail. In this case, just rerun make check without the -j option to force sequential execution. However, after the first make check, all subsequent make check should work even with the -j option.

NB: O'Mega will never produce a wrong nonvanishing matrix element due to the rare race condition described above. The only possible symptom is a vanishing scattering amplitude. Nevertheless, we aim to make the cache files obsolete by an equivalent, but faster algorthim in milestone:v2.1 (cf. ticket #271).