<div dir="ltr"><div><div><div><div><div><div><div>Hi Yuan,<br></div>Your structure seems big, many nbnd.<br></div>For such structure, smaller value of alpha_mix(1) in phonon input is helpful for convergence.<br></div>Non inclusion of alpha_mix(1) in your input file implies that the default value of 0.7 would be used.<br></div>Include alpha_mix(1) and use smaller value such as 0.2.<br></div><div><br>If that doesn't solve the problem, you may need to increase the convergence threshold tr2_ph.<br><br></div>It is also helpful to split your job along the q-points. This will enable you monitor the convergence of different q-point and adjust parameters such as alpha_mix(1) and tr2_ph accordingly.<br><br></div>Best,<br></div>Isaiah<br> </div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 2, 2017 at 12:51 PM, yuan liang <span dir="ltr"><<a href="mailto:yl4ps@virginia.edu" target="_blank">yl4ps@virginia.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear QE developers and users,<div><br></div><div>Recently I'm trying to calculate phonon dos via ph.x, however, although I can get fine convergence result at gamma point, <span style="color:rgb(0,0,0)">ph.x cannot reach convergence within 100 steps and stop automaticly at the 1st non gamma point on my mesh.</span></div><div><div><br></div><div>The material is YVO3, orthorhombic, with 4 Y atom, 4 V atom and 12 O atom per unit cell.</div></div><div><br></div><div>The QE version is 5.4.0</div><div><br></div><div>I tried both GGA PBEsol USPP and LDA USPP(from THEOS SSSP)</div><div><br></div><div><pre style="color:rgb(0,0,0)"><font face="arial, helvetica, sans-serif">Are there any methods to solve this problem? Any suggestion will be welcome.</font></pre></div><div>Here are my input files:</div><div><b>scf calculation</b></div><div><div>&control</div><div> calculation= 'scf',</div><div> restart_mode= 'from_scratch',</div><div> prefix='YVO3_exc',</div><div> pseudo_dir = '...',</div><div> outdir= '...',</div><div> wf_collect=.true.,</div><div> tprnfor=.true., tstress=.true.</div><div>/</div><div>&system</div><div> ibrav = 8,</div><div> celldm(1) = 9.9893, </div><div> celldm(2) = 1.0581, </div><div> celldm(3) = 1.4296,</div><div> nat = 20,</div><div> ntyp = 3,</div><div> ecutwfc = 60,</div><div> ecutrho = 480,</div><div> ecfixed = 60,</div><div> qcutz = 20,</div><div> q2sigma = 5,</div><div> occupations= 'smearing', smearing='gauss', degauss=0.01,</div><div>/</div><div>&electrons</div><div> mixing_beta = 0.4,</div><div> mixing_mode = 'plain',</div><div> conv_thr = 1.0d-10,</div><div>/ </div><div>ATOMIC_SPECIES</div><div> Y 88.906 y_lda_v1.4.uspp.F.UPF</div><div> V 50.942 v_lda_v1.4.uspp.F.UPF</div><div> O 15.999 o_lda_v1.2.uspp.F.UPF</div><div>ATOMIC_POSITIONS crystal</div><div> Y 0.97830 0.07150 0.25000</div><div> ...</div><div> O 0.18720 0.20040 0.55663</div><div>K_POINTS automatic</div><div> 6 6 4 0 0 0</div></div><div><b>phonon calculation on grid</b></div><div><div>&inputph</div><div> prefix='YVO3_exc',</div><div> outdir='...',</div><div> recover=.true.,</div><div> <font color="#ff0000"><b>ldisp=.true</b></font>.,</div><div> nq1=6,</div><div> nq2=6,</div><div> nq3=4,</div><div> tr2_ph=1.0d-14,</div><div> fildyn='YVO3_dyn.G',</div><div> amass(1)=80.906,</div><div> amass(2)=50.942,</div><div> amass(3)=15.999,</div><div>/</div><div>0.000000 0.000000 0.000000</div></div><div><br></div><div>Best regards,</div><div><br></div><div>Yuan Liang</div><div>Physics Department, </div><div>University of Virginia</div></div>
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