<div dir="ltr">
<p dir="auto">For future reference, I report here the explanation and workaround by Lorenzo Paulatto that seems to work in this case:</p><p dir="auto">"The phonon code checks if modes are degenerate by symmetrizing a random matrix and checking if the eigenvalues are the same. For sufficiently large systems there are going to be accidental degeneracies. Try to uncomment the line</p><p dir="auto">!!#define __UNIFORM_DISTRIB</p><p dir="auto">
in PHonon/PH/random_matrix.f90 and recompile"</p>
</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, May 7, 2020 at 8:51 AM Paolo Giannozzi <<a href="mailto:p.giannozzi@gmail.com" target="_blank">p.giannozzi@gmail.com</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"><div dir="ltr"><div dir="ltr">On Thu, May 7, 2020 at 12:22 AM Merlin Meheut <<a href="mailto:merlin.meheut@gmail.com" target="_blank">merlin.meheut@gmail.com</a>> wrote:</div><div dir="ltr"><br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">I am not sure how to implement you solution</div></blockquote><div><br></div><div>it is not a "solution", unfortunately: just an empirical observation, based on many similar reports. Sometimes it is sufficient to make the system closer to the expected symmetry to see the problem disappear. It may not be the case here, though</div><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">(and also, why is that not happening with version 5.3?)</div></blockquote><div><br></div><div>changes in the symmetry algorithm?<br></div><div> <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">As a first guess, I would be tempted to give more accurate cell parameters, or more accurate positions, but this seems weird, because those come from a relaxation (calculation='vc-relax') with pw.x, and further, pw.x (whatever the version) finds all the symetries of the structure, before and after relaxation.</div></blockquote><div><br></div><div>this is the correct and expected behavior, but there are thresholds that decide whether a symmetry is there or not. In some unfortunate cases, these thresholds may give inconsistencies between the self-consistent and the phonon code.<br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">[...] I modified it to return the value of wrk that creates an error, and it gives me wrk=0.640333821809072, in the second case (jpert.eq.ipert). This large value seems contradictory with your suggestion, as this is quite far from 1. For a "not close enough" symmetry, I would have expected something smaller, dont you think? <br></div></blockquote><div><br></div><div>you are likely right</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div></div><div>Would you have some guidance on how to proceed further? <br></div></div></blockquote><div><br></div><div>unfortunately no: I have lost track of how symmetry works in the phonon code since a long time. I suspect that these lines appearing in the output:<br></div><div> Eigenvectors exchange needed 23 235</div><div>are in some way related to your problem, but it is impossible to say more without an extensive investigation. <br></div><div><br></div><div>Paolo<br></div><div><br>
</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div></div><div><br></div><div>Best regards, <br></div><div><br></div><div>Merlin Méheut <br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le mar. 5 mai 2020 à 21:54, Paolo Giannozzi <<a href="mailto:p.giannozzi@gmail.com" target="_blank">p.giannozzi@gmail.com</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Typically, this error happens with cells that are very close to a given symmetry, but not close enough.</div><div><br></div><div>Paolo<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, May 3, 2020 at 1:16 AM Merlin Meheut <<a href="mailto:merlin.meheut@gmail.com" target="_blank">merlin.meheut@gmail.com</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"><div dir="ltr"><div>Dear PWSCF users, <br></div><div><br></div><div>I am trying to compute phonon properties of a garnet (spacegroup Ia-3d) structure, and the computation is working perfectly well with version 5.3.0, but I have an error message for versions 6.2, 6.3MaX, 6.4 and 6.4.1 (I did not compile 6.5, yet):</div><div><br></div><div>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br> Error in routine set_irr_sym_new (1622):<br> wrong representation<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br><br> stopping ...<br></div><div><br></div><div> Would you have an idea on the origin of this error? <br></div><div><br></div><div>the scf input: <br></div><div> &control<br> calculation = 'scf',<br> restart_mode = 'from_scratch' ,<br> prefix = 'GROSS',<br> disk_io = 'default' ,<br> pseudo_dir = './',<br> outdir ='./',<br> tprnfor = .true.,<br> tstress = .true.,<br> disk_io = 'low',<br> dt = 30 ,<br> nstep = 1300 ,<br> etot_conv_thr = 5.d-5,<br> forc_conv_thr = 5.d-4,<br>/&end<br>&system<br> ibrav = 0 ,<br> celldm(1)=22.36869,<br> nat =80, ntyp = 4, ecutwfc = 80.0<br> ecutrho = 320.0,<br>/&end<br><br> &electrons<br> electron_maxstep = 80,<br> conv_thr = 1.d-11,<br> mixing_mode = 'plain',<br> startingwfc = 'atomic',<br> mixing_beta = 0.5,<br>/&end<br><br>&ions<br>/&end<br><br> &cell<br> wmass = 0.01,<br> cell_dynamics = 'damp-w',<br> press_conv_thr = 0.2<br>/&end<br><br>ATOMIC_SPECIES<br> Al 26.9815 Al.pbe2.UPF<br> Ca 39.9626 Ca.pbe-spn-rrkjus_psl.1.0.0.UPF<br> Si 27.9769 Si.pbe2.UPF<br> O 15.9949 O.pbe.UPF<br><br>CELL_PARAMETERS (alat= 22.36869000)<br> 0.509146517 0.509146517 0.509146517<br> -0.509146517 0.509146517 0.509146517<br> -0.509146517 -0.509146517 0.509146517<br>ATOMIC_POSITIONS (crystal)<br>Al -0.000000000 0.000000000 -0.000000000<br>Al 0.000000000 0.500000000 0.500000000<br>Al 0.500000000 0.500000000 0.000000000<br>Al 0.000000000 0.500000000 0.000000000<br>Al 0.500000000 0.000000000 0.500000000<br>Al 0.500000000 0.000000000 0.000000000<br>Al 0.000000000 0.000000000 0.500000000<br>Al 0.500000000 0.500000000 0.500000000<br>Ca 0.125000000 0.250000000 0.875000000<br>Ca 0.375000000 0.750000000 0.625000000<br>Ca 0.375000000 0.875000000 0.250000000<br>Ca 0.875000000 0.750000000 0.125000000<br>Ca 0.125000000 0.625000000 0.750000000<br>Ca 0.625000000 0.250000000 0.375000000<br>Ca 0.250000000 0.875000000 0.875000000<br>Ca 0.750000000 0.625000000 0.625000000<br>Ca 0.625000000 0.125000000 0.750000000<br>Ca 0.875000000 0.375000000 0.250000000<br>Ca 0.750000000 0.125000000 0.125000000<br>Ca 0.250000000 0.375000000 0.375000000<br>Si 0.625000000 0.625000000 0.250000000<br>Si 0.875000000 0.875000000 0.750000000<br>Si 0.250000000 0.125000000 0.625000000<br>Si 0.750000000 0.875000000 0.375000000<br>Si 0.375000000 0.375000000 0.750000000<br>Si 0.750000000 0.375000000 0.875000000<br>Si 0.250000000 0.625000000 0.125000000<br>Si 0.125000000 0.125000000 0.250000000<br>Si 0.375000000 0.250000000 0.125000000<br>Si 0.625000000 0.750000000 0.875000000<br>Si 0.125000000 0.750000000 0.375000000<br>Si 0.875000000 0.250000000 0.625000000<br>O 0.690298613 0.005517534 0.607713976<br>O 0.613231510 0.494482466 0.195816147<br>O 0.809701387 0.582584637 0.304183853<br>O 0.695816147 0.386768490 0.005517534<br>O 0.392286024 0.494482466 0.309701387<br>O 0.309701387 0.994482466 0.392286024<br>O 0.886768490 0.917415363 0.892286024<br>O 0.107713976 0.309701387 0.494482466<br>O 0.804183853 0.005517534 0.386768490<br>O 0.386768490 0.505517534 0.804183853<br>O 0.392286024 0.113231510 0.582584637<br>O 0.695816147 0.917415363 0.190298613<br>O 0.190298613 0.417415363 0.695816147<br>O 0.804183853 0.190298613 0.917415363<br>O 0.082584637 0.607713976 0.386768490<br>O 0.994482466 0.113231510 0.304183853<br>O 0.304183853 0.613231510 0.994482466<br>O 0.107713976 0.582584637 0.113231510<br>O 0.886768490 0.195816147 0.494482466<br>O 0.607713976 0.505517534 0.690298613<br>O 0.113231510 0.082584637 0.107713976<br>O 0.417415363 0.195816147 0.309701387<br>O 0.505517534 0.190298613 0.892286024<br>O 0.892286024 0.690298613 0.505517534<br>O 0.809701387 0.607713976 0.005517534<br>O 0.195816147 0.994482466 0.613231510<br>O 0.505517534 0.304183853 0.113231510<br>O 0.417415363 0.386768490 0.607713976<br>O 0.607713976 0.886768490 0.417415363<br>O 0.613231510 0.892286024 0.917415363<br>O 0.304183853 0.082584637 0.809701387<br>O 0.994482466 0.892286024 0.190298613<br>O 0.082584637 0.309701387 0.195816147<br>O 0.195816147 0.809701387 0.082584637<br>O 0.917415363 0.392286024 0.613231510<br>O 0.005517534 0.886768490 0.695816147<br>O 0.690298613 0.304183853 0.582584637<br>O 0.892286024 0.417415363 0.886768490<br>O 0.113231510 0.804183853 0.505517534<br>O 0.582584637 0.804183853 0.690298613<br>O 0.494482466 0.809701387 0.107713976<br>O 0.190298613 0.392286024 0.994482466<br>O 0.494482466 0.695816147 0.886768490<br>O 0.582584637 0.613231510 0.392286024<br>O 0.386768490 0.107713976 0.082584637<br>O 0.005517534 0.107713976 0.809701387<br>O 0.917415363 0.690298613 0.804183853<br>O 0.309701387 0.695816147 0.417415363<br><br>K_POINTS {crystal}<br>1<br> 0.25 0.25 0.25 1<br></div><div><br></div><div>the phonon input: <br></div><div>Liz m1<br> &inputph<br> amass(1)= 26.9815, <br> amass(2)= 39.96259,<br> amass(3)= 27.9769 ,<br> amass(4)= 15.9949 ,<br> tr2_ph = 1.0D-16,<br> prefix='GROSS',<br> fildyn='mat.Gross-rel-vdwdf2.80Ryx4-bald-qe613',<br> lraman=.false.,<br> epsil =.true.,<br> trans =.true.,<br> zue = .true.,<br> outdir='./'<br>/&end<br>0.0000000 0.000000 0.00000<br></div><div><br></div><div>And the ph.x output with the error: <br></div><div><br> Program PHONON v.6.2 starts on 3May2020 at 1: 5:55 <br><br> This program is part of the open-source Quantum ESPRESSO suite<br> for quantum simulation of materials; please cite<br> "P. Giannozzi et al., J. Phys.:Condens. Matter 21 395502 (2009);<br> "P. Giannozzi et al., J. Phys.:Condens. Matter 29 465901 (2017);<br> URL <a href="http://www.quantum-espresso.org" target="_blank">http://www.quantum-espresso.org</a>", <br> in publications or presentations arising from this work. More details at<br> <a href="http://www.quantum-espresso.org/quote" target="_blank">http://www.quantum-espresso.org/quote</a><br><br> Parallel version (MPI & OpenMP), running on 36 processor cores<br> Number of MPI processes: 36<br> Threads/MPI process: 1<br><br> MPI processes distributed on 1 nodes<br> R & G space division: proc/nbgrp/npool/nimage = 36<br><br> Reading data from directory:<br> ./GROSS.save/<br><br> IMPORTANT: XC functional enforced from input :<br> Exchange-correlation = PBE ( 1 4 3 4 0 0)<br> Any further DFT definition will be discarded<br> Please, verify this is what you really want<br><br> file Ca.pbe-spn-rrkjus_psl.1.0.0.UPF: wavefunction(s) 3S renormalized<br> <br> Parallelization info<br> --------------------<br> sticks: dense smooth PW G-vecs: dense smooth PW<br> Min 259 259 66 15862 15862 2076<br> Max 260 260 67 15866 15866 2081<br> Sum 9351 9351 2407 571093 571093 74869<br> <br>Eigenvectors exchange needed 23 235<br>Eigenvectors exchange needed 23 236<br>Eigenvectors exchange needed 23 237<br>Eigenvectors exchange needed 24 235<br>Eigenvectors exchange needed 25 236<br>Eigenvectors exchange needed 25 237<br><br> Calculation of q = 0.0000000 0.0000000 0.0000000<br><br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br> Error in routine set_irr_sym_new (1622):<br> wrong representation<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br><br> stopping ...<br></div><div><br></div><div>Thanks<br></div><div><br></div><div><br>-- <br><div dir="ltr"><div dir="ltr">Merlin Méheut<br>adresse labo:<br>GET - OMP - Université Paul Sabatier <br>14 avenue Edouard Belin<br>31400 Toulouse<br>FRANCE <br>tel: (+33) 5 61 33 26 17<br><br></div></div></div></div>
_______________________________________________<br>
Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">www.max-centre.eu/quantum-espresso</a>)<br>
users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="noreferrer" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></blockquote></div><br clear="all"><br>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div>Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>Phone +39-0432-558216, fax +39-0432-558222<br><br></div></div></div></div></div>
_______________________________________________<br>
Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">www.max-centre.eu/quantum-espresso</a>)<br>
users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="noreferrer" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></blockquote></div><br clear="all"><br>-- <br><div dir="ltr"><div dir="ltr">Merlin Méheut<br>adresse labo:<br>GET - OMP - Université Paul Sabatier <br>14 avenue Edouard Belin<br>31400 Toulouse<br>FRANCE <br>tel: (+33) 5 61 33 26 17<br><br></div></div></div>
_______________________________________________<br>
Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">www.max-centre.eu/quantum-espresso</a>)<br>
users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="noreferrer" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></blockquote></div><br clear="all"><br>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div>Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>Phone +39-0432-558216, fax +39-0432-558222<br><br></div></div></div></div></div></div>
</blockquote></div><br clear="all"><br>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div>Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>Phone +39-0432-558216, fax +39-0432-558222<br><br></div></div></div></div></div>