> I was not sure whether this problem caused by empty-band number, so I > increase nbnd. ? You should increase nbnd if you see "too few bands" message? in *.ph.out file.
Bests, Eyvaz. ? ? ________________________________ From: GAO Zhe <[email protected]> To: Eyvaz Isaev <eyvaz_isaev at yahoo.com>; PWSCF Forum <pw_forum at pwscf.org> Sent: Sunday, July 17, 2011 11:33 AM Subject: Re: [Pw_forum] ph.x cannot reach convergence within 100 steps Thank you very much, Prof. Isaev. I tried all of 'scf', 'relax' and 'vc-relax' before ph.x, but got the same problem in each case~ I was not sure whether this problem caused by empty-band number, so I increase nbnd. It may too large for my model~ Now, I am trying to change the values of alpha_mix(1) and nmix_ph for a better convergent. Thank you, again ^_^ -- GAO Zhe CMC Lab, MSE, SNU, Seoul, S.Korea At 2011-07-16 16:39:40?"Eyvaz?Isaev"?<eyvaz_isaev at yahoo.com> wrote: Hi, > > > >>Recently, I am trying to calculate phonon dispersion via ph.x. However, in some cases, ph.x cannot reach convergence within 100 steps and stop >automaticly. >? >1. You should? perform 'scf', not 'vc-relax' before phonon calculations. >2. You have a rather large system (nbnd=100), but used alpha_mix(1) by default >(0.7). Try it around 0.1. >3. Try changing nmix_ph (by default 4). >4. If this does not help change 'maxter=100' in phcom.f90 and recompile. > >Bests, >Eyvaz. > > >------------------------------------------------------------------- >Prof. Eyvaz Isaev, >Department of Physics, Chemistry, and Biology (IFM), Linkoping University, >Sweden >Theoretical Physics Department, Moscow State Institute of Steel & Alloys, >Russia, >isaev at ifm.liu.se, eyvaz_isaev at yahoo.com > > >________________________________ >From: GAO?Zhe <flux_ray12 at 163.com> >To: PWSCF Forum <pw_forum at pwscf.org> >Sent: Saturday, July 16, 2011 7:40 AM >Subject: [Pw_forum] ph.x cannot reach convergence within 100 steps > > >Dear QE developer and users: >Recently, I am trying to calculate phonon dispersion via ph.x. However, in >some cases, ph.x cannot reach convergence within 100 steps and stop >automaticly. >I have tested the convergent lattice parameter, cut-off energy and k-points >(M-P grid), and the thresholds of force and stress were also very low. Even if >I increase the tr2_ph from 1.0d-12 (default) to 1.0d-10, the |ddv_scf|^2? >values was around 10^(-6) or 10^(-7) magnitude. The problem usually occurred >at the second q-point, but sometimes, even if lucky enough, it would >definitely occur at the third q-point (4 q-points in 3x3x3 case). >Are there any methods to solve this problem? Any suggestion will be welcome. >Calculations were used GGA-PBE USPP. >This is my input file: >cat >W25.relax.in <<EOF >&control >???? calculation = 'vc-relax' , >???? disk_io = 'low' , >???? prefix = 'W' , >???? outdir = '$TempDIR/' , >???? pseudo_dir = '$PseudoDIR/' , >???? etot_conv_thr = 1.0d-12 , >???? forc_conv_thr = 1.0d-4 , >/ >&system >???? ibrav = 1 , >???? celldm(1) = ******* , >???? nat = ** , >???? ntyp = 3 , >???? nbnd = 100 , >???? ecutwfc = 47.5 , >???? ecutrho = 450 , >???? occupations = 'smearing' , >???? smearing = 'mp' , >???? degauss = 0.003 , >/ >&electrons >???? conv_thr = 1.0d-12 , >???? startingpot = 'atomic' , >???? startingwfc = 'atomic+random' , >???? diagonalization = 'cg' , >???? electron_maxstep = 150 , >/ >&ions >???? ion_dynamics = 'bfgs' , >/ >&cell >???? cell_dynamics = 'bfgs' , >???? press_conv_thr = 0.01 , >/ >ATOMIC_SPECIES >? V?? 50.9415?? V.pbe-n-van.UPF >? W?? 183.800?? W.pbe-nsp-van.UPF >? C?? 12.0110?? C.pbe-van_ak.UPF >ATOMIC_POSITIONS crystal >? V?? 0.50? 0.50? 0.00 >........... >? C?? 0.50? 0.50? 0.50 >K_POINTS automatic >13? 13? 13?? 0? 0? 0 >EOF >echo -e "? Relaxing Structure...\c" >$MPIBIN/mpirun -n 6 pw.x -npool 2 <W.relax.in >W.relax.out >echo -e " DONE" > >cat >W.ph.in <<EOF >Phonon Calculation >&inputph >???? outdir = '$TempDIR/' , >???? prefix = 'W' , >???? ldisp = .true. , >???? nq1 = 3 , >???? nq2 = 3 , >???? nq3 = 3 , >???? tr2_ph = 1.0d-10 , >???? fildyn = 'W.dyn' , >/ >EOF >echo -e "? Calculating Dynamic Matrix...\c" >$MPIBIN/mpirun -n 6 ph.x -npool 2 <W.ph.in >W.ph.out >echo -e " DONE" > > > >-- >GAO Zhe >CMC Lab, MSE, SNU, Seoul, S.Korea > > > >_______________________________________________ >Pw_forum mailing list >Pw_forum at pwscf.org >http://www.democritos.it/mailman/listinfo/pw_forum > > > _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110717/47d6cba3/attachment-0001.htm
