Molcas Forum

Hanros

Member

Registered: 2017-12-26

Posts: 17

Parallel run Openmolcas

Hi

I'm trying to calculate a file with quite a large active space  with 10 electrons in 10 orbitals in RAS2 plus 2p orbitals and the 6 2p electrons in RAS1. The file calculates 120 excited states using HEXS however it becomes stuck at the section "CI expansion specifications". The computing resources I'm using are Openmp with 16 threads with 500hours as the soft time limit and  MOLCAS_MEM=2048 on a HPC cluster.

the files are sometimes stuck on the section  "CI expansion specifications" or on the SCF convergence. The jobs have certainly stopped as the load level is zero.

()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()

                                              &RASSCF

                                   only a single process is used
                      available to each process: 2.0 GB of memory, 16 threads
()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()

I believe the issue may be with the parallel scheme (Openmp) chosen for Openmolcas. I don't think the use of 16 threads has increased the MOLCAS_MEM as it is defined per process. Perhaps THe overhead is simply too high? Could someone please advise me on how to counter this and would you recommend OpenMPI parallel environment instead?

Last edited by Hanros (2018-08-16 18:19:34)