NPAR and NSIM
Posted: Sun Apr 01, 2012 7:47 am
I just started a new project where I am using Ti, and/or Si, and O in a large supercell. I'm running molecular dynamics with on the order of 100 atoms in my supercell using the above atoms. I have been working a lot on this for the past week and the runs keep crashing. I have done molculare dynamics the Mg and H over the years and never had this problem. I'm getting segmentation faults... not even the first electronic step will go at times... at other times it runs for a while and then crashes. I have figured out that I need to be sure not to let the atoms get too hot with too big of a time step... put the runs still crash. I am fairly sure that I'm missing something about how to pick nodes/cores/NPAR/NSIM. Any wisdon? Should I be considering how much RAM I need on each node? Most importantly: on the VASP manual page from NPAR it suggests testing different NPAR values if you are doing MD. But I could use some wisdom so I know what set of NPAR's would be smart to test.... and what NSIM/node/core combination goes with each "NPAR test". Any help would be much appreciated. If I'm not making sense or you need more infor don't hesitate to let me know and I will work more on my question. Thanks!!!