Setting up the parallel environment

In addition to the installation steps described in Section 1.6 (see page ) you just have to set the variable PARA_ARCH to MPI, i.e. in sh/bash/ksh syntax:

export PARA_ARCH=MPI

This will cause sysname to append the string _mpi to the system name and the scripts like jobex will take the parallel binaries by default. To call the parallel versions of the programs RIDFT, RDGRAD, DSCF, GRAD or MPGRAD from your command line without their explicit path, expand your $PATH environment variable to:

export PATH=$TURBODIR/bin/`sysname`:$PATH

The usual binaries are replaced now by scripts that prepare the input for a parallel run and start mpiexec (or poe on IBM SP3) automatically. The number of CPUs that shall be used can be chosen by setting the environment variable PARNODES:

export PARNODES=8

On all systems TURBOMOLE is using the MPI library that has been shipped with your operating system. On Linux, the freely available, portable implementation of MPI, MPICH2 (http://www-unix.mcs.anl.gov/mpi/mpich/), is used. The scripts that initialize the MPD ring (mpdboot) and start the parallel binaries (mpiexec) are located in the $TURBODIR/mpirun_scripts/MPICH2 directory. These scripts require Python version 2.2 or later, which should be available in any reasonable Linux distribution.

Note: the parallel TURBOMOLE modules (except RICC2) need an extra server running in addition to the clients. This server is included in the parallel binaries and it will be started automatically--but this results in one additional task that does not need any CPU time. So if you are setting PARNODES to N, N+1 tasks will be started. If a queueing system is used, check that N+1 processes will be provided.