Hello,
I want to restart EOM-CC3 calculations from the previous calculations, to save some time, since the EOM-CC3 calculation calculate just one root per run. How can I do this?
Searching the documentation, the RESTART_EOM_CC3 option is possible, but I think I need to put another configuration on the first run to save the files.
Best regards,
Alan Guilherme Falkowski.
The restart options were developed for a much earlier version of Psi, so it’s likely not reasonable to try to keep the necessary files in place for this in Psi4. However, I would also suggest that this option is really only valuable when one runs out of iterations for a single excited state/root. If you want multiple roots, the option probably wouldn’t save you all that much time because the ground-state calculation and the EOM-CCSD guesses are still pretty inexpensive relative to the CC3 excited state calc. @Rollin_King can correct me if I’m off base here.
Yep, what @crawdad said. Since Psi went to auto-naming its temporary files, it always takes me awhile to work out how to name and reuse them. But in this case, it would be of nearly negligible benefit.
Thank you @jmisiewicz, @crawdad and @Rollin_King.
Something seems strange to me, the EOM-CC3 calculation for a root is taking too long to run. Is this implementation parallelized? What are the input flags to parallel this type of execution?
Fundamentally, an excited-state CC3 sigma vector is 4 times the work of a ground-state iteration. I haven’t used the code in a bit but 2 keywords may be important. There is an explicit loop in the main EOM CC3 engine that may be threaded if you have sufficient memory.
T3_WS_INCORE = boolean [false]
Set this to True which keeps some 3-virtual index quantities in core memory. That’s a big ask but CC3 is so cpu intensive you may find it useful anyway.
CC_NUM_THREADS = integer [1]
Increase this to use the explicit threading. You may be limited by the amount of memory available on the machine so some experimentation will be required. Anything less than your # of cores is worth trying.
I will test these flags. Thank you very much!