<div dir="ltr"><div><div><div><div><div>Dear Paolo, <br><br></div>Thank you for your reply.<br><br></div>The elphmat internal variable should not be a werewolf as it represent <u_k | dV_scf/dR | u_k+q >**2, a variable that directly enters physicals quantities like the zero-point renormalization.<br><br></div>Following your advice I could narrowed it down so far between revision 5000 and 5300 (see below).<br><br></div>Best, <br><br></div>Samuel<br><div><div><div><br><br>QE 4.0.3 q = ( 0.000000000 0.333333333 0.000000000<br>elphmat(:,:,:)**2 0.1192375<br>elphmat(:,:,:)**2 0.9861288<br>elphmat(:,:,:)**2 1.354492<br>elphmat(:,:,:)**2 0.3075966<br><br>espresso-r5000 q = ( 0.000000000 0.333333333 0.000000000<br>elphmat(:,:,:)**2 0.1192375<br>elphmat(:,:,:)**2 0.9861288<br>elphmat(:,:,:)**2 1.354492<br>elphmat(:,:,:)**2 0.3075966<br><br>espresso-r5300 q = ( 0.000000000 0.333333333 0.000000000<br>elphmat(:,:,:)**2 0.1192376<br>elphmat(:,:,:)**2 0.9861288<br>elphmat(:,:,:)**2 1.348592<br>elphmat(:,:,:)**2 0.3134981<br><br>espresso-r5667 q = ( 0.000000000 0.333333333 0.000000000<br>elphmat(:,:,:)**2 0.1192375 <br>elphmat(:,:,:)**2 0.9861288<br>elphmat(:,:,:)**2 1.348592<br>elphmat(:,:,:)**2 0.3134981<br><br>espresso-r7654 q = ( 0.000000000 0.333333333 0.000000000<br>elphmat(:,:,:)**2 0.1192375<br>elphmat(:,:,:)**2 0.9861287<br>elphmat(:,:,:)**2 1.348593<br>elphmat(:,:,:)**2 0.3134982<br><br>QE 5.1.2 q = ( 0.000000000 0.333333333 0.000000000 )<br>elphmat(:,:,:)**2 0.1192376<br>elphmat(:,:,:)**2 0.9861287<br>elphmat(:,:,:)**2 1.348592<br>elphmat(:,:,:)**2 0.3134981<br></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">2015-06-27 16:30 GMT+01:00 Paolo Giannozzi <span dir="ltr"><<a href="mailto:p.giannozzi@gmail.com" target="_blank">p.giannozzi@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>You should first of all verify whether the quantity you print depends upon the specific choice of irreps/degeneracies/phases of wavefunctions/phases of the moon. If you are really sure that the quantity you print should not vary across versions, a safe but slow way to figure out what happened when and maybe why is to start from a svn version close to 4.0.3 and go up until something happens.<br><br></div>Paolo<br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Fri, Jun 26, 2015 at 8:23 PM, Samuel Poncé <span dir="ltr"><<a href="mailto:samuel.pon@gmail.com" target="_blank">samuel.pon@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr"><div><div><div><div><div>Dear developers of QE, <br><br></div>I noticed a backward compatibility issue on the electron-phonon matrix element between QE 4.0.3 and 5.1.2. <br><br></div>I was wondering if it was a bug and if not, what was the reason.<br><br></div><div>I added the following line in the two versions of the code in PHonon/PH/elphon.f90<br><br>if (ik==215) then<br>write(*,*)'elphmat(:,:,:)**2',SUM((REAL(REAL(elphmat(:,:,:))))**2)+SUM((REAL(AIMAG(elphmat(:,:,:))))**2)<br></div><div><br></div><div>This should be a physically relevant quantity that should not change between version (the order of the mode changed but it is not an issue).<br></div><div><br></div>Test: <br></div>6x6x6 q-grid same pseudo, tol and inputs parameters <br><br></div>There is 16 irr q-points:<br><br><div> ( 16q-points):<br> N xq(1) xq(2) xq(3)<br> 1 0.000000000 0.000000000 0.000000000<br> 2 -0.166666667 0.166666667 -0.166666667<br> 3 -0.333333333 0.333333333 -0.333333333<br> 4 0.500000000 -0.500000000 0.500000000<br> 5 0.000000000 0.333333333 0.000000000<br> 6 -0.166666667 0.500000000 -0.166666667<br> 7 0.666666667 -0.333333333 0.666666667<br> 8 0.500000000 -0.166666667 0.500000000<br> 9 0.333333333 0.000000000 0.333333333<br> 10 0.000000000 0.666666667 0.000000000<br> 11 0.833333333 -0.166666667 0.833333333<br> 12 0.666666667 -0.000000000 0.666666667<br> 13 0.000000000 -1.000000000 0.000000000<br> 14 0.666666667 -0.333333333 1.000000000<br> 15 0.500000000 -0.166666667 0.833333333<br> 16 -0.333333333 -1.000000000 0.000000000<br><br></div><div>All the elphmat**2 are the same (up to 4 digits) for 13 of the 16 q-points. For example<br></div><div><br>QE 5.1.2 q = ( -0.166666667 0.166666667 -0.166666667 )</div><div>elphmat(:,:,:)**2 0.5446267<br>elphmat(:,:,:)**2 0.5446253<br>elphmat(:,:,:)**2 0.9506719<br>elphmat(:,:,:)**2 0.9506719<br><br> freq ( 1) = 9.137536 [THz] = 304.795384 [cm-1]<br> freq ( 2) = 9.137536 [THz] = 304.795384 [cm-1]<br> freq ( 3) = 15.052865 [THz] = 502.109513 [cm-1]<br> freq ( 4) = 39.653912 [THz] = 1322.712114 [cm-1]<br> freq ( 5) = 39.653912 [THz] = 1322.712114 [cm-1]<br> freq ( 6) = 40.741956 [THz] = 1359.005377 [cm-1]<br><br>QE 4.0.3 q = ( -0.166666667 0.166666667 -0.166666667 )<br>elphmat(:,:,:)**2 0.5446267<br>elphmat(:,:,:)**2 0.9506719<br>elphmat(:,:,:)**2 0.5446266<br>elphmat(:,:,:)**2 0.9506719<br><br> omega( 1) = 9.137611 [THz] = 304.799915 [cm-1]<br> omega( 2) = 9.137611 [THz] = 304.799915 [cm-1]<br> omega( 3) = 15.052641 [THz] = 502.105399 [cm-1]<br> omega( 4) = 39.653770 [THz] = 1322.716173 [cm-1]<br> omega( 5) = 39.653770 [THz] = 1322.716173 [cm-1]<br> omega( 6) = 40.741800 [THz] = 1359.009209 [cm-1]<br><br><br></div><div>But the three irr-q<b> 5, 10</b> and <b>16</b> are NOT the same:<br>QE 5.1.2 q = ( 0.000000000 0.333333333 0.000000000 )<br>elphmat(:,:,:)**2 0.1192376<br>elphmat(:,:,:)**2 0.9861287<br>elphmat(:,:,:)**2 1.348592<br>elphmat(:,:,:)**2 0.3134981<br><br></div><div> freq ( 1) = 11.633039 [THz] = 388.036416 [cm-1]<br> freq ( 2) = 11.633039 [THz] = 388.036416 [cm-1]<br> freq ( 3) = 16.188917 [THz] = 540.004156 [cm-1]<br> freq ( 4) = 39.110566 [THz] = 1304.588071 [cm-1]<br> freq ( 5) = 39.110566 [THz] = 1304.588071 [cm-1]<br> freq ( 6) = 40.947507 [THz] = 1365.861806 [cm-1]<br><br></div><div>QE 4.0.3 q = ( 0.000000000 0.333333333 0.000000000 <br></div><div>elphmat(:,:,:)**2 0.3075966<br>elphmat(:,:,:)**2 1.354492<br>elphmat(:,:,:)**2 0.1192375<br>elphmat(:,:,:)**2 0.9861288<br><br> omega( 1) = 11.633152 [THz] = 388.042751 [cm-1]<br> omega( 2) = 11.633152 [THz] = 388.042751 [cm-1]<br> omega( 3) = 16.188922 [THz] = 540.007888 [cm-1]<br> omega( 4) = 39.110425 [THz] = 1304.592025 [cm-1]<br> omega( 5) = 39.110425 [THz] = 1304.592025 [cm-1]<br> omega( 6) = 40.947359 [THz] = 1365.865939 [cm-1]<br><br></div><div>As you can see the difference for the 0,1/3,0 is not huge but significant. As a matter of fact when<br></div><div>I'm using the dvscf produced by QE 4 or 5 for that irr-q it can lead to physically very different results. Therefore I would like to know which dvscf file is correct (QE 4 or 5)?<br><br></div><div>Thank you, <br><br></div><div>Best Regards, <br><br></div><div>Samuel Ponce <br>Department of Materials, University of Oxford<br></div><div><br><br><br></div></div>
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Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
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