[Pw_forum] plot with gnuplot
Dear Mansoureh, A better way to put the graphs into WORD is to first convert the eps file into png (or other format like jpg. Personally I prefer png for its small file size and lossless compression). To do this, if you are Windows user, Photoshop will work fine. If you use Linux, GIMP can also perform this conversion easily. If you would like to use commands, you may install Imagemagick. Then type, for example, convert -density 300 input.eps output.png 300 is the width resolution in dpi. If you omit this, you turn out to have a low resolution png like what you saw before. On Wed, 2008-08-13 at 07:50 +0330, Mansoureh Pashangpour wrote: > Dear all > I am using gnuplot to plot DOS plots,but when I make its output as a > postscript file and then use it to make its pdf and send it to > word.doc ,its resolution decreases.Does anyone a good sugesstion to > solve this problem? > good luck > Mansoureh > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum -- S.H. Lee M.Phil Physics Division The CUHK Graduate School ___ ?x?? - Yahoo! Messenger ???]?W?o???W?r???f http://messenger.yahoo.com.hk
[Pw_forum] Stress tensor from pw.x and cp.x
Dear Nicola, Thank you very much for giving me some ideas about the issue! Indeed, I am using ultrasoft pseudopotentials. And therefore, I've set the nrb's carefully using the formula, "nr1b=2*rcut*nr1/Lx", and make it a bit larger than values calculated with this equation. However, you remind me that I may not have a high enough ecutrho. My ecutwfc is 35 Ryd and 150 for ecutrho. This might not be enough... I will try a higher value on ecutrho to see if there are any difference. If there is still the problem, I will then have to try the QE-4 package. Thank you very much! -- S.H. Lee M.Phil Physics Division The CUHK Graduate School On Thu, 2008-05-22 at 02:36 -0400, Nicola Marzari wrote: > > Dear Lawrence, > > > the only suggestions that comes to mind is this - the stress tensors > converges to its "true" values more slowly with energy cutoff then > other quantities. Usually the error at standard cutoffs is > fairly "rigid", i.e. due to contributions that are not sensitive to > the chemical environment, and so you can even correct for that > empirically. > > CP and PWscf have a different way of treating augmentation charges, > so that's the only major difference that comes to mind - but it would > apply to ultrasoft pseudo (that's why posting your input would have helped). > > Bottom line - let's use QE-4.0 (i.e. download it now) and retest > with increasing cutoff, and if you are using ultrasoft pseudopotentials, > throw in for good measure a high charge density cutoff (10-12 times the > wavefunctions). In CP, test also for the box grid size (nr1b...), > increasing values. And then maybe post again, at least the results > and an input file. Of course, if it is ultrasoft, and your nr1b is not > really that good, that could explain it right away. > > > nicola > > > > Lawrence Lee wrote: > > Dear all, > > > > Since my calculation is really simple, I am not going to attach my input > > file here. I use the QE-3.1.1 code, and perform scf calculation using > > pw.x on a 64-atom cell, which has a perfect fcc structure, using only > > the gamma point. I obtain a stress tensor then. > > > > Later on I use exactly the same structure and cell and cut-off's, but > > using cp.x to perform a damped dynamics on the electrons, keeping the > > atoms fixed. I also obtain a stress tensor. > > > > However, the results between pw.x and cp.x is different, apart from the > > difference in units. The cp.x results are generally about 5~10 GPa above > > that of pw.x. > > > > I find this quite confusing. Is the method of calculation of stress > > tensor by these two programmes different? > > > > Thank you very much for solving my doubt. ___ ?x?? - Yahoo! Messenger ???]?W?o???W?r???f http://messenger.yahoo.com.hk
[Pw_forum] Stress tensor from pw.x and cp.x
Dear all, Since my calculation is really simple, I am not going to attach my input file here. I use the QE-3.1.1 code, and perform scf calculation using pw.x on a 64-atom cell, which has a perfect fcc structure, using only the gamma point. I obtain a stress tensor then. Later on I use exactly the same structure and cell and cut-off's, but using cp.x to perform a damped dynamics on the electrons, keeping the atoms fixed. I also obtain a stress tensor. However, the results between pw.x and cp.x is different, apart from the difference in units. The cp.x results are generally about 5~10 GPa above that of pw.x. I find this quite confusing. Is the method of calculation of stress tensor by these two programmes different? Thank you very much for solving my doubt. -- S.H. Lee M.Phil Physics Division The CUHK Graduate School ___ ?x?? - Yahoo! Messenger ???]?W?o???W?r???f http://messenger.yahoo.com.hk
[Pw_forum] Output and parallelization problem in pw.x
Dear all, I have serveral problems about pw.x. The performance of pw.x running in parallel under inter-node, is unreasonbly poor (about 25%). Later, I type sar to check, and find that something called "contextswitch" appears very frequently. But when pw.x is run under intra-node process, the problem did not occur and the performance become very good (>90%). I think that "contextswitch" cause the problem. But why did it occur and how to fix the problem? The second problem is about output file of pw.x. I want to get the stress tensor of each step of a pw.x (not cp.x) molecular dynamic run. I know that they exist in the standard output file. But the format is very inconvenient for further proccessing. Do anyone know is there any flag which can be specified to output a file of stress? Thanks a lot! Lawrence ___ YM - ??? http://messenger.yahoo.com.hk -- next part -- An HTML attachment was scrubbed... URL: /pipermail/attachments/20070212/49d2989e/attachment.htm
[Pw_forum] About Pseudo-Potential generation
Dear Paolo, Thanks very much for your answering. But I still do not fully understand your answers about fractional occupation. In my example, some may use [Ne]3s1.5 for Mg. And you said that this is for computational convenience. Can you elaborate more on this point? By the way, if this config is used, should I correspondingly set zval=1.5 , instead of let it default? Thanks a lot! Lawrence ___ YM - ??? http://messenger.yahoo.com.hk -- next part -- An HTML attachment was scrubbed... URL: /pipermail/attachments/20070125/87cda318/attachment.htm
[Pw_forum] About Pseudo-Potential generation
Dear all, I have serveral questions about PP generation. Please forgive me if there are any stupid question as I am a new in this field. (1) Comparing Rabe-Rappe-Kaxiras-Joannopoulos and Troullier-Martin pseudization, it seems that the former is simpler. But actually which one is better? Do each of them have their particular advantages. (2) What's the difference between using one channel as the local PP and pseudizing the all electron potential. (3) Sometimes, one will use fractional occupation such as [Ne]3s1.5 for Mg. Why's that? (4) If I want to do high pressure calculation later, does it mean that I must use a small core radius. Thanks for helping me! Lawrence ___ YM - ??? http://messenger.yahoo.com.hk -- next part -- An HTML attachment was scrubbed... URL: /pipermail/attachments/20070123/7243f1bc/attachment.htm
[Pw_forum] difference between molecular dynamics of PW and that of CPMD
Dear sir / madam, I am a new user of pwscf. I know that pw can do molecular dynamics. What is the difference between that and CPMD? Besides, do you know how to restart the run in pw.x? For example, if I have made a run of 400 steps with dt = 20 atomic time unit, but now I find it insufficient. I need the run to have 2000 steps, say. Do I have any method to proceed the run without doing it from the first step again? Lawrence. ___ YM - ??? http://messenger.yahoo.com.hk -- next part -- An HTML attachment was scrubbed... URL: /pipermail/attachments/20070104/f365bc2a/attachment.htm
