I have a system that has 1 k-point, 54 atoms,
NGZ=80. I'm running an AIMD simulation on VASP version 5.4.4
The supercomputer has 32 cores/node. It's a LINUX cluster linked by Infiniband, modern multicore machine. I was wondering what would be the best way to select parameters and request resources to get an efficient and fast calculation. Here are some scenarios I've considered. I'm curious what would be the "best" method (in terms of efficiency and speed).
- Based on what I read here
- I should request something like 19 bands (152/8). Maybe set NBANDS=160 to request an even 20 cores.
- Would I then set NCORE=20 in my INCAR file and request 20 cores on 1 node?
- Or would it be better to set NCORE = 10. And then request something like 2 nodes and 10 cores per node? or would that create too much communication overhead and slow down the simulation?
- If I decide to use # of cores = # of atoms = 54
- Would I set NCORE=32, and then request 54 cores over 2 nodes (32 on 1 node + 22 on the second)? Or 9 cores/node and 6 nodes?
- Can't I just request the whole node? 1 node, 32 cores
- so then set NCORE=32 and I just request the whole node. However the VASP manual suggests against this because that would make NPAR=1
- this confuses me a bit because I would assume 32 cores on one node would be more efficient than having cores across several nodes communicating with each other