<div dir="ltr"><div><div><div><div><div><div><div>Dear Prof. Marks,<br><br></div> Thank you very much for your answers ! I am pretty sure that your "intuition" will save a lot of computation time !<br></div> Just one last question: I have another system , a supercell formed by 15 InP zinc blend cells along [111] (hexagonal representation of the cubic lattice) and 3 InP wurtzite cells. They are aligned along the hexagonal "c" axis.<br></div> <wbr> Comparing the gaps of the respective bulks and this supercell (same calculation parameters) , I believe that the SCF cycle (here, it is not a lattice optimization) stopped at a local minimum.<br></div> My question is : in this case (regular SCF cycle and InP cells), would you change any of your previous answers ?<br></div> Thank you again !!<br></div> All the best,<br></div> Luis<br><br></div><div class="gmail_extra"><br><div class="gmail_quote">2017-01-25 17:56 GMT-02:00 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"><div dir="ltr">Inlined is my intuition, which does not have to be completely right.<div class="gmail_extra"><br><div class="gmail_quote"><span class="">On Wed, Jan 25, 2017 at 11:32 AM, Luis Ogando <span dir="ltr"><<a href="mailto:lcodacal@gmail.com" target="_blank">lcodacal@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>Dear Prof. Marks (and Wien2k community),<br>
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After a recent discussion about "difficult" optimizations in this mailing list (subject: "Mixer surprise when using PBE0 hybrid on-site functional"), I would like ask you for an advice.<br>
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I have a system with:<br>
* 5 rings with C, H and N atoms<br>
* 100 atoms with P1 symmetry <br>
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* the rings are out of a plane<br>
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* vacuum along y and z<br>
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I know that this is a very hard optimization problem, so I would like to kindly ask:<br>
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1) Do you believe that MSEC3a will work better than MSR1a in such a case ?<br></div></div></div></div></div></div></div></div></blockquote><div><br></div></span><div>I would switch to MSEC3a, use SLOW or reduce the GREED to 0.1 only if you see indications of problems. If the system is a decent insulator and the experimental positions are quite good you may have no problems. At the end I would switch back to MSR1a certainly for a system with OH as the positions of the hydrogens can be quite soft. It can take quite some time to get the rotations of the OH bond distance right as Wien2k uses cartesian coordinates not polars. Which of the 3 is best -- I am not sure.</div><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div dir="ltr"><div><div><div><div><div><div>
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2) Do you recommend using -it, -vec2pratt and -noHinv options with run_lapw ?<br></div></div></div></div></div></div></div></blockquote><div><br></div></span><div>I use -it -noHinv -vec2pratt. Sometimes you need to do an occasional full diagonalization (touch .fulldiag) as the iterative method is less stable (it adds a little noise). In my personal version I have added back the old -itn option so this is done automatically every few steps. </div><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div dir="ltr"><div><div><div><div><div>
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3) Should I reduce TRUST to 0.5 (I am using LDA and experimental values for the initial atomic positions) ?<br></div></div></div></div></div></div></blockquote><div><br></div></span><div>Probably not. TRUST 0.5 would be if it is taking much too large steps which tends (in my experience) to occur more with soft electronic modes such as one has with d and f electrons. </div><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div dir="ltr"><div><div><div><div>
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4) Should I use SLOW in case.inm ? <br></div></div></div></div></div></blockquote><div><br></div></span><div>See my answer to 1) </div><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div dir="ltr"><div><div><div>
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Many thanks in advance.<br>
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All the best,<br>
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Luis<br>
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</blockquote></span></div><span class="HOEnZb"><font color="#888888"><br><br clear="all"><div><br></div>-- <br><div class="m_2547980773262265899gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><span style="font-size:12.8px">Professor Laurence Marks</span><br></div><div dir="ltr"><span style="font-size:12.8px">"Research is to see what everybody else has seen, and to think what nobody else has thought", </span><span style="font-size:12.8px">Albert Szent-Gyorgi</span><br><a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a> ; <span style="font-size:12.8px">C<wbr>orrosion in 4D: </span><a href="http://MURI4D.numis.northwestern.edu" style="font-size:12.8px" target="_blank">MURI4D.numis.northwestern.edu</a><div><span style="font-size:12.8px">Partner of the CFW 100% program for gender equity, </span><a href="http://www.cfw.org/100-percent" style="font-size:12.8px" target="_blank">www.cfw.org/100-<wbr>percent</a></div><div>Co-Editor, Acta Cryst A</div></div></div></div></div></div></div></div></div></div></div>
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