On Sun, 14 Jan 2007 stewart at cnf.cornell.edu wrote: DS> Hi everyone,
hi derek. happy new year. DS> I have been looking at a fairly large system (160 atoms) with a nanowire DS> between two (111) leads in PWscf. I have converged the system, but now I DS> would like to plot out the charge density. I have the xml files for charge DS> density and spin density. However, I am running into insufficient virtual DS> memory complaints when running pp.x, even when I run the parallel version. hmm, you are running binaries compiled with intel fortran, right? did you try increasing the stack size (using 'ulimit -s')? what is the exact error message? could you try generating a core dump (run 'ulimit -c unlimited', then pw.x as usual), then 'idb pw.x core.XXXX' and on the idb prompt type 'where' to generate a stack trace, so we can see where it crashes. DS> Does anyone know if it is possible to read the xml files directly with some DS> visualization packages (XCrysDens). The xml files are fairly large (58 MB), DS> so I may be running into file size limit problems. Is it always necessary DS> to run pp.x and then generate plot output? if the stack size 'trick' does not help, you can think about reducing the number of grid points used for plotting. in CPMD using half the grid in each direction (i.e. 1/8th of the data!) is the default and usually is quite sufficient to get very nice pictures. you should be able to set the output grid in pp.x, but if that still is not sufficient, you might want to try as a matter of last resort an NSCF calculation from a converged potential/wavefunction with a smaller real space density cutoff (and thus grid) and use that to get the output. cheers, axel. DS> DS> I have been using version 3.1.1 for these calculations. DS> DS> Thanks, DS> DS> Derek DS> DS> DS> ################################ DS> Derek Stewart, Ph. D. DS> Scientific Computation Associate DS> 250 Duffield Hall DS> Cornell Nanoscale Facility (CNF) DS> Ithaca, NY 14853 DS> stewart (at) cnf.cornell.edu DS> (607) 255-2856 DS> _______________________________________________ DS> Pw_forum mailing list DS> Pw_forum at pwscf.org DS> http://www.democritos.it/mailman/listinfo/pw_forum DS> -- ======================================================================= Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu http://www.cmm.upenn.edu Center for Molecular Modeling -- University of Pennsylvania Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323 tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425 ======================================================================= If you make something idiot-proof, the universe creates a better idiot.
