Cannot use more than 10 nodes: Licensed number of users already reached.

[SDas]

Hi,

I am running a few calculations simultaneously in a supercomputer cluster. The system is quite big and I need atleast 10 nodes (48 cores each) for each calculation. But I can only run one such calculation at a time. That is, if I already have an atkpython job running on 10 nodes, and I submit another concurrently, it stops running with the following error: Licensed number of users already reached. (Full log file is attached as 'final.log').

Also, I get the same error if I attempt to run a solitary single job on 20 nodes.

I assume it is because there is a maximum limit of the no. of licenses that can be in use concurrently. But I want to understand why a single job cannot be run on 20 nodes (It would make each calculation incredibly faster). Is there any parallelization option that can help me avoid this issue?

Thanks,
SD

[Ulrik G. Vej-Hansen]

Yes, it does indeed look like you run out of dp licenses. Please file a ticket on SolvnetPlus, there we can better help with license-related questions.

[Anders Blom]

Running in parallel on many (>100) cores doesn't always make calculations run faster. It really depends if there are enough independent tasks to parallelize over, such as energy points on the NEGF contour or k-points. For most calculations, the benefit of going from 200 to 400 cores is far less than 2x so you would be better off running 2 calculations on 200 cores than 1 calculation on 400 anyway.