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Dear Holger,<br><br>Thank your for responding. <br><br>> next to the suggestion of Lorenzo to use the bfgs algorithm, the point in <br>> your input is the missing timestep for the cell dynamics with the <br>> Wentzcovitch algorithm. (see quantum-wiki) It looks like you got a <br>> non-evolving (or almost non-evolving) dynamics.<br><br>I have done the BFGS. And get the similar results. Both of Wentzcovitch and BFGS of QE<br>undervalue the cell parameters of anatase from my test. I'll show you my BFGS results soon.<br>Thank you for your point out that timestep is missing. But I don't know how to choose a proper<br>value for it. I'll google it later but not now. I think BFGS maybe handle the cell parametter calculation.<br><br>> A second, more general remark on you input: Set up only the variables you <br>> really need (as Axel pointet out in several mails before: every non-written <br>> line is per definition a correct one).<br>> It doesn't make any sense to set numbers with more than 14 digits (the code <br>> does not handle this) and in most cases 8 digits is more than enough, <br><br>I see. Thank you<br><br>> Think about, why you set etot_conv_thr so tight (don't mix it up with <br>> conv_thr, which seemed to be sloppy for this calculation ), while you set <br>> forc_conv_thr to be really sloppy? (Btw, is there any reason to set the <br>> cutoffs/thresholds to such precision?)<br><br>Many litterature doing so. The force threshold is usually set as 0.03eV and 0.05eV<br>for larger system. the cutoff in literature can be 380 or 400eV sometimes.<br>I'm only doing repeat work and learning how to do a perfect calculation.<br>Also the conv_thr and etot_conv_thr is taken from CASTEP calculation directly. Others<br>doing so of the same system is the only reason. I'm a beginner of PWscf and DFT<br>calculation. So I think doing repeat work of others and discuss with skilled people may be the <br>best way for me. What I'm doing now is something more like a homework rather than<br>the research work. I'm learning to using PWscf. Thank you for your help.<br><br><br><font size="4"><span style="font-family: Lucida Handwriting,Cursive;">Vega Lew</span></font><br>PH.D Candidate in Chemical Engineering<br>
State Key Laboratory of Materials-oriented Chemical Engineering<br>College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br><br><br><br /><hr />Connect to the next generation of MSN Messenger <a href='http://imagine-msn.com/messenger/launch80/default.aspx?locale=en-us&source=wlmailtagline' target='_new'>Get it now! </a></body>
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