<div dir="ltr"><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;color:rgb(0,0,0)">Sorry Peter, this is not working on the DFT eigenvectors and convergence is not relevant. It is doing a SVD of {YY+lamdba*SY}} to generate a Penrose-Moore pseudoinverse. The vectors of an SVD are not unique within a phase term.</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, Dec 19, 2025 at 12:41 PM Peter Blaha <<a href="mailto:peter.blaha@tuwien.ac.at">peter.blaha@tuwien.ac.at</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">"different results":<br>
I'd expect it is either not fully self-consistent for the <br>
quantity/accuracy of interest (do on both computers 100 more <br>
iterations), or different hardware (AVXxx, different cpu, cache, ...), <br>
software like mkl-, ifort- versions or compiler options or ...<br>
<br>
<br>
<br>
Am 19.12.2025 um 17:35 schrieb Guoping Zhang:<br>
> Dear Profs. Blaha and Marks and wien users,<br>
> <br>
> I have a question on how the new Mixer is implemented as it gives me<br>
> different results on different computers. Different results mean that<br>
> the eigenvalues differ by 10^-6 ry, so the wavefunctions are even<br>
> worse. I am using wien2k_13 version, but there is no difference for<br>
> newer versions.<br>
> <br>
> <br>
> In FprojmemR1m.F, call DGESVD gets SVD of Vect, but SVD normally<br>
> produces an arbitrary sign for U and VT for the same Vect like<br>
> vect 1 1 1.7542057564<br>
> vect 1 2 1.7522638412<br>
> vect 2 1 1.7441856025<br>
> vect 2 2 1.7425017533<br>
> <br>
> In one case, my U is<br>
> <br>
> <br>
> debug3c.outputm:MMT91 U VT 1 1 -0.7091042206 -0.7074733729<br>
> debug3c.outputm:MMT91 U VT 1 2 -0.7051036834 -0.7067399994<br>
> debug3c.outputm:MMT91 U VT 2 1 -0.7051036834 -0.7067399994<br>
> debug3c.outputm:MMT91 U VT 2 2 0.7091042206 0.7074733729<br>
> <br>
> Another case has<br>
> <br>
> debug11.outputm:MMT91 U VT 1 1 0.7091042206 0.7074733728<br>
> debug11.outputm:MMT91 U VT 1 2 -0.7051036834 0.7067399994<br>
> debug11.outputm:MMT91 U VT 2 1 0.7051036834 -0.7067399994<br>
> debug11.outputm:MMT91 U VT 2 2 0.7091042206 0.7074733728<br>
> <br>
> I run 4 iterations to activate the mixer. When I diff case.scf, these two<br>
> cases have no difference to the last digit,<br>
> <br>
> But after the mixing, it differs a lot though the total energy is the<br>
> same (which is not my interest).<br>
> <br>
> My questions are (1) whether the new mixer finally uses some products<br>
> like (U x VT) to generate the new charge density, and (2) whether you<br>
> have examples that I use to verify this arbitrary sign does not matter.<br>
> <br>
> Thank you so much in advance!<br>
> <br>
> Best wishes,<br>
> <br>
> Guoping<br>
> <br>
> <br>
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<br>
-- <br>
-----------------------------------------------------------------------<br>
Peter Blaha, Inst. f. Materials Chemistry, TU Vienna, A-1060 Vienna<br>
Email: <a href="mailto:peter.blaha@tuwien.ac.at" target="_blank">peter.blaha@tuwien.ac.at</a><br>
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</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr">Emeritus Professor Laurence Marks (Laurie)<div>Northwestern University<br><div><a href="http://www.numis.northwestern.edu" target="_blank">Webpage</a> and <a href="http://scholar.google.com/citations?user=zmHhI9gAAAAJ&hl=en" target="_blank">Google Scholar link</a></div><div>"Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Györgyi</div></div></div></div>