For future reference, I report here the explanation and workaround by Lorenzo Paulatto that seems to work in this case:
"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 !!#define __UNIFORM_DISTRIB in PHonon/PH/random_matrix.f90 and recompile" On Thu, May 7, 2020 at 8:51 AM Paolo Giannozzi <[email protected]> wrote: > On Thu, May 7, 2020 at 12:22 AM Merlin Meheut <[email protected]> > wrote: > > I am not sure how to implement you solution >> > > 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 > > (and also, why is that not happening with version 5.3?) >> > > changes in the symmetry algorithm? > > 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. >> > > 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. > > [...] 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? >> > > you are likely right > > Would you have some guidance on how to proceed further? >> > > 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: > Eigenvectors exchange needed 23 235 > are in some way related to your problem, but it is impossible to say more > without an extensive investigation. > > Paolo > > >> Best regards, >> >> Merlin Méheut >> >> Le mar. 5 mai 2020 à 21:54, Paolo Giannozzi <[email protected]> a >> écrit : >> >>> Typically, this error happens with cells that are very close to a given >>> symmetry, but not close enough. >>> >>> Paolo >>> >>> On Sun, May 3, 2020 at 1:16 AM Merlin Meheut <[email protected]> >>> wrote: >>> >>>> Dear PWSCF users, >>>> >>>> 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): >>>> >>>> >>>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >>>> Error in routine set_irr_sym_new (1622): >>>> wrong representation >>>> >>>> >>>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >>>> >>>> stopping ... >>>> >>>> Would you have an idea on the origin of this error? >>>> >>>> the scf input: >>>> &control >>>> calculation = 'scf', >>>> restart_mode = 'from_scratch' , >>>> prefix = 'GROSS', >>>> disk_io = 'default' , >>>> pseudo_dir = './', >>>> outdir ='./', >>>> tprnfor = .true., >>>> tstress = .true., >>>> disk_io = 'low', >>>> dt = 30 , >>>> nstep = 1300 , >>>> etot_conv_thr = 5.d-5, >>>> forc_conv_thr = 5.d-4, >>>> /&end >>>> &system >>>> ibrav = 0 , >>>> celldm(1)=22.36869, >>>> nat =80, ntyp = 4, ecutwfc = 80.0 >>>> ecutrho = 320.0, >>>> /&end >>>> >>>> &electrons >>>> electron_maxstep = 80, >>>> conv_thr = 1.d-11, >>>> mixing_mode = 'plain', >>>> startingwfc = 'atomic', >>>> mixing_beta = 0.5, >>>> /&end >>>> >>>> &ions >>>> /&end >>>> >>>> &cell >>>> wmass = 0.01, >>>> cell_dynamics = 'damp-w', >>>> press_conv_thr = 0.2 >>>> /&end >>>> >>>> ATOMIC_SPECIES >>>> Al 26.9815 Al.pbe2.UPF >>>> Ca 39.9626 Ca.pbe-spn-rrkjus_psl.1.0.0.UPF >>>> Si 27.9769 Si.pbe2.UPF >>>> O 15.9949 O.pbe.UPF >>>> >>>> CELL_PARAMETERS (alat= 22.36869000) >>>> 0.509146517 0.509146517 0.509146517 >>>> -0.509146517 0.509146517 0.509146517 >>>> -0.509146517 -0.509146517 0.509146517 >>>> ATOMIC_POSITIONS (crystal) >>>> Al -0.000000000 0.000000000 -0.000000000 >>>> Al 0.000000000 0.500000000 0.500000000 >>>> Al 0.500000000 0.500000000 0.000000000 >>>> Al 0.000000000 0.500000000 0.000000000 >>>> Al 0.500000000 0.000000000 0.500000000 >>>> Al 0.500000000 0.000000000 0.000000000 >>>> Al 0.000000000 0.000000000 0.500000000 >>>> Al 0.500000000 0.500000000 0.500000000 >>>> Ca 0.125000000 0.250000000 0.875000000 >>>> Ca 0.375000000 0.750000000 0.625000000 >>>> Ca 0.375000000 0.875000000 0.250000000 >>>> Ca 0.875000000 0.750000000 0.125000000 >>>> Ca 0.125000000 0.625000000 0.750000000 >>>> Ca 0.625000000 0.250000000 0.375000000 >>>> Ca 0.250000000 0.875000000 0.875000000 >>>> Ca 0.750000000 0.625000000 0.625000000 >>>> Ca 0.625000000 0.125000000 0.750000000 >>>> Ca 0.875000000 0.375000000 0.250000000 >>>> Ca 0.750000000 0.125000000 0.125000000 >>>> Ca 0.250000000 0.375000000 0.375000000 >>>> Si 0.625000000 0.625000000 0.250000000 >>>> Si 0.875000000 0.875000000 0.750000000 >>>> Si 0.250000000 0.125000000 0.625000000 >>>> Si 0.750000000 0.875000000 0.375000000 >>>> Si 0.375000000 0.375000000 0.750000000 >>>> Si 0.750000000 0.375000000 0.875000000 >>>> Si 0.250000000 0.625000000 0.125000000 >>>> Si 0.125000000 0.125000000 0.250000000 >>>> Si 0.375000000 0.250000000 0.125000000 >>>> Si 0.625000000 0.750000000 0.875000000 >>>> Si 0.125000000 0.750000000 0.375000000 >>>> Si 0.875000000 0.250000000 0.625000000 >>>> O 0.690298613 0.005517534 0.607713976 >>>> O 0.613231510 0.494482466 0.195816147 >>>> O 0.809701387 0.582584637 0.304183853 >>>> O 0.695816147 0.386768490 0.005517534 >>>> O 0.392286024 0.494482466 0.309701387 >>>> O 0.309701387 0.994482466 0.392286024 >>>> O 0.886768490 0.917415363 0.892286024 >>>> O 0.107713976 0.309701387 0.494482466 >>>> O 0.804183853 0.005517534 0.386768490 >>>> O 0.386768490 0.505517534 0.804183853 >>>> O 0.392286024 0.113231510 0.582584637 >>>> O 0.695816147 0.917415363 0.190298613 >>>> O 0.190298613 0.417415363 0.695816147 >>>> O 0.804183853 0.190298613 0.917415363 >>>> O 0.082584637 0.607713976 0.386768490 >>>> O 0.994482466 0.113231510 0.304183853 >>>> O 0.304183853 0.613231510 0.994482466 >>>> O 0.107713976 0.582584637 0.113231510 >>>> O 0.886768490 0.195816147 0.494482466 >>>> O 0.607713976 0.505517534 0.690298613 >>>> O 0.113231510 0.082584637 0.107713976 >>>> O 0.417415363 0.195816147 0.309701387 >>>> O 0.505517534 0.190298613 0.892286024 >>>> O 0.892286024 0.690298613 0.505517534 >>>> O 0.809701387 0.607713976 0.005517534 >>>> O 0.195816147 0.994482466 0.613231510 >>>> O 0.505517534 0.304183853 0.113231510 >>>> O 0.417415363 0.386768490 0.607713976 >>>> O 0.607713976 0.886768490 0.417415363 >>>> O 0.613231510 0.892286024 0.917415363 >>>> O 0.304183853 0.082584637 0.809701387 >>>> O 0.994482466 0.892286024 0.190298613 >>>> O 0.082584637 0.309701387 0.195816147 >>>> O 0.195816147 0.809701387 0.082584637 >>>> O 0.917415363 0.392286024 0.613231510 >>>> O 0.005517534 0.886768490 0.695816147 >>>> O 0.690298613 0.304183853 0.582584637 >>>> O 0.892286024 0.417415363 0.886768490 >>>> O 0.113231510 0.804183853 0.505517534 >>>> O 0.582584637 0.804183853 0.690298613 >>>> O 0.494482466 0.809701387 0.107713976 >>>> O 0.190298613 0.392286024 0.994482466 >>>> O 0.494482466 0.695816147 0.886768490 >>>> O 0.582584637 0.613231510 0.392286024 >>>> O 0.386768490 0.107713976 0.082584637 >>>> O 0.005517534 0.107713976 0.809701387 >>>> O 0.917415363 0.690298613 0.804183853 >>>> O 0.309701387 0.695816147 0.417415363 >>>> >>>> K_POINTS {crystal} >>>> 1 >>>> 0.25 0.25 0.25 1 >>>> >>>> the phonon input: >>>> Liz m1 >>>> &inputph >>>> amass(1)= 26.9815, >>>> amass(2)= 39.96259, >>>> amass(3)= 27.9769 , >>>> amass(4)= 15.9949 , >>>> tr2_ph = 1.0D-16, >>>> prefix='GROSS', >>>> fildyn='mat.Gross-rel-vdwdf2.80Ryx4-bald-qe613', >>>> lraman=.false., >>>> epsil =.true., >>>> trans =.true., >>>> zue = .true., >>>> outdir='./' >>>> /&end >>>> 0.0000000 0.000000 0.00000 >>>> >>>> And the ph.x output with the error: >>>> >>>> Program PHONON v.6.2 starts on 3May2020 at 1: 5:55 >>>> >>>> This program is part of the open-source Quantum ESPRESSO suite >>>> for quantum simulation of materials; please cite >>>> "P. Giannozzi et al., J. Phys.:Condens. Matter 21 395502 >>>> (2009); >>>> "P. Giannozzi et al., J. Phys.:Condens. Matter 29 465901 >>>> (2017); >>>> URL http://www.quantum-espresso.org";, >>>> in publications or presentations arising from this work. More >>>> details at >>>> http://www.quantum-espresso.org/quote >>>> >>>> Parallel version (MPI & OpenMP), running on 36 processor cores >>>> Number of MPI processes: 36 >>>> Threads/MPI process: 1 >>>> >>>> MPI processes distributed on 1 nodes >>>> R & G space division: proc/nbgrp/npool/nimage = 36 >>>> >>>> Reading data from directory: >>>> ./GROSS.save/ >>>> >>>> IMPORTANT: XC functional enforced from input : >>>> Exchange-correlation = PBE ( 1 4 3 4 0 0) >>>> Any further DFT definition will be discarded >>>> Please, verify this is what you really want >>>> >>>> file Ca.pbe-spn-rrkjus_psl.1.0.0.UPF: wavefunction(s) >>>> 3S renormalized >>>> >>>> Parallelization info >>>> -------------------- >>>> sticks: dense smooth PW G-vecs: dense smooth >>>> PW >>>> Min 259 259 66 15862 15862 >>>> 2076 >>>> Max 260 260 67 15866 15866 >>>> 2081 >>>> Sum 9351 9351 2407 571093 571093 >>>> 74869 >>>> >>>> Eigenvectors exchange needed 23 235 >>>> Eigenvectors exchange needed 23 236 >>>> Eigenvectors exchange needed 23 237 >>>> Eigenvectors exchange needed 24 235 >>>> Eigenvectors exchange needed 25 236 >>>> Eigenvectors exchange needed 25 237 >>>> >>>> Calculation of q = 0.0000000 0.0000000 0.0000000 >>>> >>>> >>>> >>>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >>>> Error in routine set_irr_sym_new (1622): >>>> wrong representation >>>> >>>> >>>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >>>> >>>> stopping ... >>>> >>>> Thanks >>>> >>>> >>>> -- >>>> Merlin Méheut >>>> adresse labo: >>>> GET - OMP - Université Paul Sabatier >>>> 14 avenue Edouard Belin >>>> 31400 Toulouse >>>> FRANCE >>>> tel: (+33) 5 61 33 26 17 >>>> >>>> _______________________________________________ >>>> Quantum ESPRESSO is supported by MaX ( >>>> www.max-centre.eu/quantum-espresso) >>>> users mailing list [email protected] >>>> https://lists.quantum-espresso.org/mailman/listinfo/users >>> >>> >>> >>> -- >>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, >>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy >>> Phone +39-0432-558216, fax +39-0432-558222 >>> >>> _______________________________________________ >>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso >>> ) >>> users mailing list [email protected] >>> https://lists.quantum-espresso.org/mailman/listinfo/users >> >> >> >> -- >> Merlin Méheut >> adresse labo: >> GET - OMP - Université Paul Sabatier >> 14 avenue Edouard Belin >> 31400 Toulouse >> FRANCE >> tel: (+33) 5 61 33 26 17 >> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) >> users mailing list [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > > -- > Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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