Parallel Runs

Some of the TURBOMOLE modules are parallelized using the message passing interface (MPI) for distributed and shared memory machines or, in the case of dscf and ricc2 also with OpenMP for shared memory machines. The list of parallelized programs includes presently:

• ridft -- parallel ground state non-hybrid DFT energies including RI-J and the multipole accelerated RI (MA-RI-J)
• rdgrad -- parallel ground state gradients from ridft calculations
• dscf -- Hartree-Fock and DFT ground state calculations for all available DFT functionals, without the usage of RI-J approximation
• grad -- parallel ground state gradients from dscf calculations
• ricc2 -- parallel ground and excited state calculations of energies and gradients at MP2 and CC2 level using RI, as well as energy calculations of other wave function models, see chapter 9.5.
• mpgrad -- parallel conventional (i.e. non-RI) MP2 energy and gradient calculations. Please note that RI-MP2 is one to two orders of magnitue faster than conventional MP2, so even serial RI-MP2 will be faster than parallel MP2 calculations.
• NumForce -- this script can used for a trivial parallelization of the numerical displaced coordinates.

Additional keywords neccessary for parallel runs with the MPI binaries are described in Chapter 15. However, those keywords do not have to be set by the users. When using the parallel version of TURBOMOLE, scripts are replacing the binaries. Those scripts prepare a usual input, run the necessary steps and automatically start the parallel programs. The users just have to set environment variables, see Sec. 3.2.1 below.

To use the OpenMP parallelization only an environment variable needs to be set. But to use this parallelization efficiently one should consider a few additional points, e.g. memory usage, which are described in Sec. 3.2.2.