:orphan: Introduction ------------ The DIRAC program suite is parallelized using the MPI2 protocol. See related works involving parallelization implementation, :cite:`Pernpointner2003`, :cite:`Saue1997`, :cite:`Knecht2008`, :cite:`Knecht2010a`, :cite:`Fleig2006`, :cite:`Fleig2001`, :cite:`Fleig2003`. Parallel run information ------------------------ My shell environment variables are not forwarded to the compute nodes. What do I have to do? Assuming you are using the pam script to submit your parallel calculation you can forward any environment variable, e.g., LD\_LIBRARY\_PATH, to the slave-node shell by adding to you pam command line:: ./pam --mpiarg="-x LD_LIBRARY_PATH" # for OpenMPI ./pam --mpiarg="-envall" # for IntelMPI and MPICH(2) In the latter case ALL environment variables will be forwarded in one shot whereas for **OpenMPI** you may need to provide the most essential environment variables individually. These may be for a typical parallel DIRAC run:: LD_LIBRARY_PATH BASDIR PATH