[Wien] SCF and symmetry

Bruno Landeros brunolanderos at hotmail.com
Tue Dec 1 19:23:36 CET 2015


Dear Peter and Laurence:
Yes, this is my first experience with Wien2k. I run the TiC and TiO2 examples and then tried with my systems. If there is a molecular crystal example please let me know, it will be very useful. 
One of the molecules in the system contains 10 H atoms and weak (F -H) hydrogen bonds so then I guess RKMax=3 is enough. I also had to increase GMAX up to 21. The link you send me will be very useful for future planification of RKMax values. 
About the Warning, I confused the *WARNING** TOTAL ENERGY IN Ry legend with an advisement of the energy units. 
Thanks again,
Bruno L

> Date: Tue, 1 Dec 2015 17:13:37 +0100
> From: pblaha at theochem.tuwien.ac.at
> To: wien at zeus.theochem.tuwien.ac.at
> Subject: Re: [Wien] SCF and symmetry
> 
> As Laurence said, you cannot compare energies with different RKmax.
> 
> Wien2k truncates RKMAX, if this would lead to matrices larger than 
> NMATMAX (specified during installation with siteconfig) to avoid 
> overloading/paging your machine (and making it "unusable").
> 
> In addition, since a case with complex matrices (no inversion) needs 
> twice the memory, it will reduce the effective matrix-size by another 
> factor of sqrt(2). Thus you got the different RKmax.
> 
> a) NEVER ignore WARNINGS (unless you read and UNDERSTAND the :WAR 
> message and it is non-critical for your case).
> 
> b) You mentioned "2 molecules ...." previously. If this contains H with 
> small RMTs, RKmax=3 is enough. Reduce it in case.in1(c).
> 
> Read http://www.wien2k.at/reg_user/faq/rkmax.html
> 
> 
> 
> On 12/01/2015 02:02 PM, Laurence Marks wrote:
> > Peter may be busy.....
> >
> > The RKM value is critically important, and you cannot compare different
> > values. I guess you are running on a single node without mpi, and the
> > RKM value has been automatically reduced to avoid going beyond the
> > memory limits (set via NMATMAX). Unless you have small minimum RMT's
> > such as for H (~0.5) an RKM value around 3 is way too small. You need to
> > repair this, either using more cores & mpi or something else.
> >
> > You sound like you have some DFT experience, but I suspect not much with
> > WIEN2K. Have you tried simpler systems first?
> >
> > ---
> > Professor Laurence Marks
> > Department of Materials Science and Engineering
> > Northwestern University
> > http://www.numis.northwestern.edu
> > Corrosion in 4D http://MURI4D.numis.northwestern.edu
> > Co-Editor, Acta Cryst A
> > "Research is to see what everybody else has seen, and to think what
> > nobody else has thought"
> > Albert Szent-Gyorgi
wien at zeus.theochem.tuwien.ac.at/index.html
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20151201/022c18ea/attachment.html>


More information about the Wien mailing list