Options for parallel runs

 Basically two possibilities exist for running QIRM, traditionally as usual binary on one node or massively parallel distributed over N nodes. As single QMC runs are independent and only the Least Square Optimization needs a communication, QIRM should scale linearly up to several 1000 nodes. This was tested up to 392 nodes on a T3E of the ZIB in Berlin.

Parallel computation can be achieved on different paths depending on the options offered by the platform:

• MPP, no MPI: On a CRAY T3E compiler extensions are available. To these functions refer the 1PE versions of the modul `hrsysmpp'. One has to set in `Makedefault' appropriately the macros `MPP=hrmympp.' and `MPI=hrmmpi_dum.'.
• MPI, no MPP: If instead an MPI implementation as MPICH or LAMMPI is available, then the above effects can be produced by MPI functions. To this end, the macros `MPP=hrmympp. hrsysmpi.' and `MPI=hrmmpi.' have to be set.
• MPP+MPI: As the compiler automatically evokes the MPP routines, the choice for the macros is given by `MPP=hrmympp.' and MPI=`hrmmpi.'.
• no MPP, no MPI: The 1PE version applies with macros `MPP=hrmympp. hrsysnomp.' and `MPI=hrmmpi_dum.'.