RKMAX is well described in the User Guide. In general I don't hold the hands of people doing simple calculations such as a GaN supercell, and I don't think other people will either -- unless you want to pay?
Research involves working things out for yourself, and only asking the harder questions as relevant. On Tue, Mar 12, 2019 at 9:57 AM umbreenrasheed <umbreenrash...@yahoo.com> wrote: > Thanks for your kind reply. > I am trying to run GaN supercell with 12 parallel processors. But want to > know about k points for this. > Please also guide me about RTMAX > > -------- Original message -------- > From: Laurence Marks <l-ma...@northwestern.edu> > Date: 3/12/19 7:34 PM (GMT+05:00) > To: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at> > Subject: Re: [Wien] (no subject) > > The number of k-points needed depends upon: > a) Whether you are doing a pre-convergence, e.g. MSR1a or a final > convergence. > b) The size of the cell > c) Whether you have a metal or an insulator (partially occupied states at > E_F) > d) The atomic number -- high Z can converge worse -- and whether you have > d/f electrons. > > I would estimate that for a metal something like a k-point density of 50 > nm^3 is good for reasonable precision. Divide by 2-4 for an insulator, > divide by 2-4 for pre-convergence and perhaps multiply by 2-4 for phonons > or high precision. > > So long as memory is not an issue, you should try and divide the k-points > across cores/nodes in an even fashion. It will also depend upon whether mpi > or threading is better on your system, this seems to vary. It is hard to > make clean statements without more information. > > For a small problem (e.g. RKM=200-500) I would tend to distribute with 1-2 > cores per k-point, e.g. use > 1:node1 > 1:node1 > 1:node1 > 1:node1 > > In .machines. (Add a :2 after the node1 to use mpi.) For a larger problem > (e.g. RKM+12000) you probably want to just run one process. For a very > large problem, e.g. RKM=30000 -- get access to a larger cluster! > > Experiment. > > > On Tue, Mar 12, 2019 at 8:34 AM umbreenrasheed <umbreenrash...@yahoo.com> > wrote: > >> How many k points should be selected for 8 parallel processors selection >> in wein2k.. >> What is general relation between the two? >> > > > -- > Professor Laurence Marks > "Research is to see what everybody else has seen, and to think what nobody > else has thought", Albert Szent-Gyorgi > www.numis.northwestern.edu ; Corrosion in 4D: > MURI4D.numis.northwestern.edu > Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent > <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cfw.org_100-2Dpercent&d=DwMGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=KScdO-7lyX_mw6Eoehq4OKL6k9Q-BUJMbO0pizP1iCY&s=Mw8WSKEEH1kbDakoqWq_PysInzFGvfLDl98Gbafpd7Q&e=> > Co-Editor, Acta Cryst A > -- Professor Laurence Marks "Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Gyorgi www.numis.northwestern.edu ; Corrosion in 4D: MURI4D.numis.northwestern.edu Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent Co-Editor, Acta Cryst A
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