Parallel execution of ADC(3)

Dear users and developers!

I would like to ask you how to make qchem (I’m using the 5.1 version) compute ADC(3) excitation energies in the parallel mode.

I understand, that it has to be done within a single node with a number of cpus (cores). The program is compiled with openMP, I am using the recommended switches (-slurm -nt … ) and it runs fine while doing the SCF, yet as soon as it goes to the correlated part (MPs, ADC iterations) it immediately switches to a single-core job.

Please, assist me here as I have not a clue what I should do. If you need information about the environment, let me know and I will try to fill you in as best as I can.

My very best regards

Sounds like you are already launching Q-Chem with multiple cores via qchem -nt X and the problem is that you do not observe any speedup with ADC calculations. There are several recommendations:

Yes! It does work fine now, when I migrated to a node with 760GB of memory. Thank you very much for the helpful advice. I will have another question concerning the performance of ADC(3) for the totally symmetric excitation and for the triples states, but I will post in with a separate topic, as it might be interesting for others as well.
My very best regards!
Marcin Andrzejak