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Dear Eyvaz and Jeff,<BR>
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Thank you very much for your help. The reason I am doing this is that I am still trying to get the phonon dispersion but using other this new technique implemented in version 4.2 of QE. Everything is going well except that for q-0 (the Gamma point), I am getting an error<BR>
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<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN style="mso-spacerun: yes"> </SPAN>from davcio : error #<SPAN style="mso-spacerun: yes"> </SPAN>20<BR><SPAN style="mso-spacerun: yes"> </SPAN>error while reading from file</FONT><BR></SPAN></P>
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The strange thing is that only for this point, I obtain such an error...I guess another guy posted that error earlier with the title Phonon calculations on the Grid. His name is shining star. <BR>
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Jeff, thanks for your suggestion as well. Actually i am still looking at the phono dispersion as a whole but found this technqieu which merges all files at the end and takes less time (I hope!).<BR>
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Regards<BR>
<BR>
Elie Moujaes<BR>
University of Nottingham<BR>
NG7 2RD<BR>
UK<BR> <BR>> Date: Tue, 1 Jun 2010 15:39:07 -0700<BR>> From: eyvaz_isaev@yahoo.com<BR>> To: pw_forum@pwscf.org<BR>> Subject: Re: [Pw_forum] start_q, last_q, start_irr, last_irr<BR>> <BR>> Dear Elie,<BR>> <BR>> --- On Wed, 6/2/10, Elie Moujaes <elie.moujaes@hotmail.co.uk> wrote:<BR>> >I am trying to get the phonon dispersion of graphene by taking each q on >its own and performing the necessary operations (i.e using start_q, >last_q, start_irr, last_irr) then merging the points all together . Can >anyone please explain to me more about these parameters.<BR>> <BR>> I never used start_irr, last_irr, but I use actively start_q and last_q parameters. After you get all dynX (including dyn0) files, just collect them in a directory and run q2r.x.<BR>> <BR>> start_q - q-point from which ph.x starts, last_q - up to this q-point from the list of q-points written in dyn0-file. I.e. if you have 12 q-points according to dyn0-file, then you can choose any combination, start_q=1, last_q=1 (usually this one is the Gamma point), or start_q=9, last_q=12 (calculate phonons for q-points from 9th to 12th), or any other combination you like (sure, last_q >= start_q).<BR>> <BR>> The same meaning for start_irr and last_irr, but for irreducible representations.<BR>> <BR>> >I read the INPUT_PH and the examples in GRID but did not actually >understand what these mean..I got that irr is irreducible representation >but how can one set these each time one runs the calculation for a q.<BR>> <BR>> Specify in ph.in files the next lines:<BR>> <BR>> *****<BR>> start_q=M<BR>> last_q=N<BR>> start_irr=I1<BR>> last_irr=I2<BR>> <BR>> If M=N, only irreducible representations (IrRep) in the range I1 - I2 will be calculated for a given (defined by M) q-point. By default, all IrRep will be calculated. <BR>> <BR>> So easy!<BR>> <BR>> Bests,<BR>> Eyvaz.<BR>> <BR>> -------------------------------------------------------------------<BR>> Prof. Eyvaz Isaev, <BR>> Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden <BR>> Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <BR>> isaev@ifm.liu.se, eyvaz_isaev@yahoo.com<BR>> <BR>> <BR>> <BR>> <BR>> <BR>> <BR>> _______________________________________________<BR>> Pw_forum mailing list<BR>> Pw_forum@pwscf.org<BR>> http://www.democritos.it/mailman/listinfo/pw_forum<BR> <br /><hr />Get a free e-mail account with Hotmail. Sign-up now. <a href='' target='_new'></a></body>
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