<div dir="rtl"><div dir="ltr">Thanks Peter and Laurie for your advises. I hope we all stay friends after my finding :)</div><div dir="ltr">The reason I didn't progress with higher k-points (I guess it doesn't work backwards, higher k-points to lower) is that I actually tried that few times and it worked (at other phase),but sometimes I got error message after the first cycle. In order to be systematic I tried to avoid that.</div><div dir="ltr">According to Peter's advice I tried again and got an error message (I can't recall if it was the same as previous) at lapw2 -up of the first cycle. uplapw2.error file showed: " 'LAPW2" - semicore band-ranges too large, ghostbands ? ". I 've deleted that file and re- run SCF while unmarking the "iterative diag" box and for some reason it worked. It worked another time, as I run 2 parallel sessions/cases with different k-points (Nd-SP and Nd-SP2).<br></div><div dir="ltr">I have good news and bad ones. The good news </div><div dir="ltr">20,000 k-points gave the same energy as 15,000 (ec 0.0001, cc 0.0001): 77040.469768(3) and 77040.469768(2), with same MMTOT (16.645, 16.647). <span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">:CHARGE convergence </span><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">-.000216 and </span><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">-.000422, for 15000 and 20000 k-points!</span></div><div dir="ltr"><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt"><br></span></div><div dir="ltr">Now for the troubling news: <span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt"><br></span></div><div dir="ltr">30,000 k-points gave something different <span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">-77040.506092(3), MMTOT=</span><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">16.091; </span><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">CHARGE convergence </span><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">-.000070.</span></div><div dir="ltr">Running the same at different case, as I said I run 2 parallel cases using the same case.struc file) I got for the same 30,000 k-points <span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">-77040.4874669(3), MMTOT=16.682; </span> <span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">CHARGE convergence </span><span style="color:rgb(0,0,10);font-family:"Liberation Serif",serif;font-size:12pt">-.000070.</span></div><div dir="ltr"><font color="#00000a" face="Liberation Serif, serif"><span style="font-size:16px">It seems that using same k-points gave me two different energies. As I understand repeating calculation should give the same results. And if these two calculations are the same, unless I did something stuoid, should give the same result. Also, the different MMTOT may suggest something wrong with the spin polarized calculations. Maybe I should do the k-test without spin polarization, as I usually do.</span></font></div><div dir="ltr"><font color="#00000a" face="Liberation Serif, serif"><span style="font-size:16px">I used both to try 60,000 points, and later I will follow Laurie's and Peter HDLOs.</span></font></div><div dir="ltr"><font color="#00000a" face="Liberation Serif, serif"><span style="font-size:16px">Victor</span></font></div><div dir="ltr"><br></div><div dir="ltr"><br></div></div><br><div class="gmail_quote"><div dir="rtl" class="gmail_attr">בתאריך יום א׳, 20 בינו׳ 2019 ב-20:01 מאת Peter Blaha <<a href="mailto:pblaha@theochem.tuwien.ac.at">pblaha@theochem.tuwien.ac.at</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I disagree with Lauries point: Eventually I want to do even an <br>
"unphysical" calculation, of course it might be you have to pay a price <br>
for it, because this unphysical model as eg. a spike in the DOS at EF. <br>
And mixer should lead to convergence, but sometimes has problems <br>
(Lauries mixer is still one of the big advantages of WIEN2k. I know <br>
other codes, which would not be able to converge a 5f system at all).<br>
<br>
In any case, put a HDLO (5f) and increase LVNS=6 first.<br>
<br>
Most importantly: why are you starting from scratch when doing the <br>
k-mesh tests. This is very error prone and in particular burns cpu-hours <br>
completely unnecessarily.<br>
<br>
One of my main "advises" is always: do an init_lapw only ONCE ! (except <br>
you have to change spheres).<br>
<br>
You will get much better internal convergence when you continue using <br>
the previous calculation:<br>
<br>
loop:<br>
runsp ....<br>
save XXX-k-points<br>
x kgen (increase the mesh always at least by a factor of 2 (maybe even 4).<br>
goto loop<br>
<br>
I'm not so much surprised about the k-mesh for a magnetic 5d-element <br>
calculation. I start with 10000 k-points for every metallic spd-element <br>
and test it with 50000 k. You may need 100 000 or even more. (optics for <br>
fcc Al is not fully converged with 1 000 000 k-points !). It does not <br>
cost much cpu, since you should start with a nearly converged calculation.<br>
<br>
Your :DIS is still quite large, try to bring it below 0.0001<br>
<br>
You can try TEMPS 0.002 as Laurence advised. This will most likely <br>
improve convergence, but most likely also reduce MMT a little bit, which <br>
is ok when you compare with room temp experiments, but not for 4k <br>
measurements ...<br>
<br>
<br>
<br>
Am 20.01.2019 um 17:50 schrieb Laurence Marks:<br>
> Sorry Fabien, I am dubious that k-points is the issue, I suspect a bad <br>
> model.<br>
> <br>
> Let me explain, repeating some things I have said before or are in the <br>
> mixer notes albeit perhaps buried.<br>
> <br>
> An "easy" assumption that many people make is that dft problems are well <br>
> posed, so have "simple" fixed-point solutions. In fact this is not true. <br>
> In reality dft problems have stacks of numerical issues which leads to <br>
> "noise". You can think about this in terms of finding the minimum of <br>
> "F(x) = x*x + Constant*Noise(x)" where Noise(x) is some randomly <br>
> generated noise. The larger Constant is, the larger the deviation is <br>
> from x=0 of the apparent minimum. Averaging over more k-points may <br>
> reduce Constant, but often in my experience does relatively little.<br>
> <br>
> A symptom of noise is poor convergence -- which is clearly what is <br>
> occurring here.<br>
> <br>
> If you improve the convergence rate you will reduce the noise. Some <br>
> suggestions:<br>
> <br>
> 1) Use HDLO and reduce RMT<br>
> 2) Reduce RMT and use HDLO<br>
> 3) Larger LM (e.g. 8)<br>
> 4) Larger gmax in case.in2 (e.g. 16)<br>
> 5) Use TEMPS 0.0018 (room temperature)<br>
> 6) Peter's suggestions<br>
> <br>
> On Sun, Jan 20, 2019 at 10:27 AM <a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a> <br>
> <mailto:<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a>> <<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a> <br>
> <mailto:<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a>>> wrote:<br>
> <br>
> Hi,<br>
> <br>
> If not too expensive, you could try more k-points (20000 and 25000)<br>
> to see if the fluctuations persist.<br>
> <br>
> Questions: how many atoms in the unit cell? Are you optimizing the<br>
> position of atoms?<br>
> <br>
> F. Tran<br>
> <br>
> On Sunday 2019-01-20 17:17, Victor Zenou wrote:<br>
> <br>
> >Date: Sun, 20 Jan 2019 17:17:55<br>
> >From: Victor Zenou <<a href="mailto:zanov@post.bgu.ac.il" target="_blank">zanov@post.bgu.ac.il</a><br>
> <mailto:<a href="mailto:zanov@post.bgu.ac.il" target="_blank">zanov@post.bgu.ac.il</a>>><br>
> >Reply-To: A Mailing list for WIEN2k users<br>
> <<a href="mailto:wien@zeus.theochem.tuwien.ac.at" target="_blank">wien@zeus.theochem.tuwien.ac.at</a><br>
> <mailto:<a href="mailto:wien@zeus.theochem.tuwien.ac.at" target="_blank">wien@zeus.theochem.tuwien.ac.at</a>>><br>
> >To: A Mailing list for WIEN2k users<br>
> <<a href="mailto:wien@zeus.theochem.tuwien.ac.at" target="_blank">wien@zeus.theochem.tuwien.ac.at</a><br>
> <mailto:<a href="mailto:wien@zeus.theochem.tuwien.ac.at" target="_blank">wien@zeus.theochem.tuwien.ac.at</a>>><br>
> >Subject: Re: [Wien] proper k-points for Nd<br>
> ><br>
> >Dear Peter, LDM and wien2k users<br>
> >I did some more calculation with energy and CHARGE convergence<br>
> criteria<br>
> >equal to 10^-4 Ryd and 10^-3, respectively. The energy usually<br>
> converged to<br>
> >1*10-5 or even 1*10^-6. Still I get energy fluctuation up to<br>
> 4*10-2 Ryd<br>
> >(please see below)<br>
> >I didn't check AFM yet, but this is not the point. The point is to get<br>
> >"stable" calculation for optimal k-points.<br>
> >I have to say that for each calculation I totally aresed all file<br>
> except<br>
> >case.struc.<br>
> >Also I used all defaults as well as gmax=12, also<br>
> rmt(min)*kmax=8.5, for all<br>
> >calculations.<br>
> >I can repeat all calculation with smaller RMT, such as 2.5, or to<br>
> check<br>
> >HDLO.<br>
> >I think I will start with smaller RMT. Any comments / suggestions?<br>
> >Victor<br>
> ><br>
> >K-pointsIBZ E [Ryd], 10-4 CHARGE convergence CHARGE DISTANCE MMTOT<br>
> >3000 208 -77040.50516761 -.000504 0.000825 16.00318<br>
> >5000 280 -77040.48748499 -.000544 0.000758 16.68523<br>
> >7500 455 -77040.51668342 -.000862 0.000183 16.62547<br>
> >10000 540 -77040.48747210 -.000817 0.000499 16.67544<br>
> >15000 840 -77040.46976815 -.000216 0.001362 16.64536<br>
> ><br>
> ><br>
> ><br>
> <br>
> <br>
> <br>
> -- <br>
> Professor Laurence Marks<br>
> "Research is to see what everybody else has seen, and to think what <br>
> nobody else has thought", Albert Szent-Gyorgi<br>
> <a href="http://www.numis.northwestern.edu" rel="noreferrer" target="_blank">www.numis.northwestern.edu</a> <<a href="http://www.numis.northwestern.edu" rel="noreferrer" target="_blank">http://www.numis.northwestern.edu</a>> ; <br>
> Corrosion in 4D: <a href="http://MURI4D.numis.northwestern.edu" rel="noreferrer" target="_blank">MURI4D.numis.northwestern.edu</a> <br>
> <<a href="http://MURI4D.numis.northwestern.edu" rel="noreferrer" target="_blank">http://MURI4D.numis.northwestern.edu</a>><br>
> Partner of the CFW 100% program for gender equity, <br>
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> Co-Editor, Acta Cryst A<br>
> <br>
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> <br>
<br>
-- <br>
--------------------------------------------------------------------------<br>
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna<br>
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982<br>
Email: <a href="mailto:blaha@theochem.tuwien.ac.at" target="_blank">blaha@theochem.tuwien.ac.at</a> WIEN2k: <a href="http://www.wien2k.at" rel="noreferrer" target="_blank">http://www.wien2k.at</a><br>
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