<div dir="ltr">Dear Prof. Marks,<div><br></div><div style> Just a quick question: if someone reduce the greed to a very low value but go back to the default values in case.inm for the last iterations, is it safe ?</div><div style>
All the best, </div><div style> Luis</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">2014-04-24 9:15 GMT-03:00 Laurence Marks <span dir="ltr"><<a href="mailto:L-marks@northwestern.edu" target="_blank">L-marks@northwestern.edu</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Why did you change case.inm away from the defaults?<br>
<br>
a) Set the greed to 0.2 not 0.005. As I have said before, this does<br>
not do what you think it does and concepts such as "reduce the mixing<br>
factor if it does not converge" are wrong. Yes, wrong. Very wrong.<br>
Completely wrong. Always wrong. To understand more please read Journal<br>
of Chemical Theory and Computation 9 (2013) 2786.<br>
<br>
b) Use MSR1, and in extreme cases perhaps MSEC3. Do not use BROYD.<br>
Perhaps reduce the greed to 0.1, almost never less than this.<br>
<br>
A little explanation. The factor of "0.005" is called the mixing<br>
<a href="http://greed.in" target="_blank">greed.in</a> the spirit of algorithm greed (e.g.<br>
<a href="http://en.wikipedia.org/wiki/Greedy_algorithm" target="_blank">http://en.wikipedia.org/wiki/Greedy_algorithm</a>). If it is too large the<br>
self-consistent iterations can become unstable. However, you rarely<br>
need to deal with this and the mixer does. If you set it too a small<br>
value (which you did) you are making the algorithm take such tiny<br>
steps that it can starve to death. The code "honors" the user setting<br>
of a very small value (at least in 12.1) under the assumption that the<br>
user knows what he/she is doing.<br>
<br>
On Thu, Apr 24, 2014 at 5:25 AM, Martin Gmitra <<a href="mailto:martin.gmitra@gmail.com">martin.gmitra@gmail.com</a>> wrote:<br>
> Dear Wien2k users,<br>
><br>
> I am doing calculations of a hexaboride films invoking: runsp_c_lapw -so<br>
> -eece<br>
> My problem is two fold:<br>
><br>
> (i) SCF calculations successfully converged for thin films (9 atomic units)<br>
> and bulk systems. I do have a problem to converge a thicker film (11 atomic<br>
> units) even TEMP broadening of 0.02 is used. The observations after 800<br>
> iterations are following:<br>
><br>
> (1) fermi energy is jumping (roughly) between two values<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= 0.3682855520<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= 0.3682855520<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= -0.7779431003<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= -0.7779431003<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= 0.3683943150<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= 0.3683943150<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= -0.7767634505<br>
> :FER : F E R M I - ENERGY(FERMI-SM.)= -0.7767634505<br>
><br>
> (2) charge distance non uniformly oscillates between 0.1 and 0.001<br>
> :DIS : CHARGE DISTANCE ( 1.1067771 for atom 4 spin 1)<br>
> 0.1064425<br>
> :DIS : CHARGE DISTANCE ( 0.0059078 for atom 6 spin 1)<br>
> 0.0013328<br>
> :DIS : CHARGE DISTANCE ( 0.0092322 for atom 6 spin 1)<br>
> 0.0015769<br>
> :DIS : CHARGE DISTANCE ( 0.0092664 for atom 6 spin 1)<br>
> 0.0015106<br>
> :DIS : CHARGE DISTANCE ( 0.5478509 for atom 4 spin 1)<br>
> 0.0466613<br>
> :DIS : CHARGE DISTANCE ( 0.0078766 for atom 6 spin 1)<br>
> 0.0014700<br>
> :DIS : CHARGE DISTANCE ( 0.9814094 for atom 4 spin 1)<br>
> 0.0939173<br>
> :DIS : CHARGE DISTANCE ( 0.0070829 for atom 6 spin 1)<br>
> 0.0015672<br>
> :DIS : CHARGE DISTANCE ( 0.0411319 for atom 4 spin 2)<br>
> 0.0053433<br>
> :DIS : CHARGE DISTANCE ( 0.0072009 for atom 6 spin 1)<br>
> 0.0014308<br>
> :DIS : CHARGE DISTANCE ( 0.1357701 for atom 4 spin 2)<br>
> 0.0150618<br>
><br>
> (3) magnetic moments are zero within spheres whereas there is<br>
> :MMTOT: SPIN MAGNETIC MOMENT IN CELL = -0.00010<br>
> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL = -0.00003<br>
><br>
> (4) my case.inm<br>
> BROYD 0.0 YES (BROYD/PRATT, extra charge (+1 for additional e), norm)<br>
> 0.005 mixing FACTOR for BROYD/PRATT scheme<br>
> 1.00 1.00 PW and CLM-scaling factors<br>
> 9999 8 idum, HISTORY<br>
><br>
> :MIX : MSEC3 REGULARIZATION: 2.50E-04 GREED: 0.005 Newton 1.000<br>
> with PRATT after 100 iterations<br>
> MIX : PRATT REGULARIZATION: 2.50E-04 GREED: 0.005<br>
><br>
> Do you have any hints how to converge the calculations?<br>
><br>
> (ii) I am running the calculations with version 12.1. The runsp_c_lapw<br>
> script has been updated (debugged) in version 13.1 but SCF diverges in my<br>
> cases (thin and thicker films).<br>
><br>
> Does anybody experience similar problem?<br>
><br>
> Best regards,<br>
> Martin Gmitra<br>
> Uni Regensburg<br>
><br>
><br>
><br>
<br>
<br>
<br>
--<br>
Professor Laurence Marks<br>
Department of Materials Science and Engineering<br>
Northwestern University<br>
<a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a> <a href="tel:1-847-491-3996" value="+18474913996">1-847-491-3996</a><br>
"Research is to see what everybody else has seen, and to think what<br>
nobody else has thought"<br>
Albert Szent-Gyorgi<br>
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</blockquote></div><br></div>