[Pw_forum] Example07
On Feb 14, 2007, at 7:28 , Paul M. Grant wrote: > The README file for example07 contains the rather cryptic remark > that, ??the k-point grids used here are NOT dense enough for a > serious calculation!?. Yet the lambda that results ranges from > 0.34 ? 0.34 depending on broadening (the experimental value for > lambda for Al is approximately 0.44). Not too bad. Increasing 16 > 16 16 and 8 8 8 to a 32 32 32 and a 16 16 16 MP grid, respectively, > yields lambdas in the range 0.34 ? 0.39. How big do I have to go? > -Paul it depends on what you want to calculate and how accurately. If you want just a rough estimate of the electron-phonon interaction coefficient lanbda, you may not need a dense grid, but in order to get an accurate number for superconducting T_c, you need it. Al is not especially nasty from this point of view, there are worse cases Paolo --- Paolo Giannozzi, Democritos and University of Udine, Italy
[Pw_forum] ambiguity in the pw2wannier.f90
On Feb 14, 2007, at 15:48 , Javad hashemifar wrote: > we found that it is necessary to add (USE basic_algebra_routines) > command to this subroutine. it looks like a compiler bug. Module bfgs_module contains (in the fortran-90 sense) subroutine bfgs that contains (as above) subroutine gdiis_step. The basic_algebra_routines module is used (in fortran-90 sense) in bfgs_module so it should propagate to gdiis_step. Other compilers do not complain. > [...] subroutine "find_mp_grid" is defined without any argument > and parenthesis but it is called with two argument : >CALL find_mp_grid(kpt_latt,mp_grid(3)) > [...] > Could this problem lead to any wrong result during the use of this > code (pw2wannier.f90). No: it would, if one called with no arguments a subroutine with two arguments (maybe only if you actually use the arguments) but the opposite shouldn't make any harm. It was anyway incorrect, so so thank you for reporting this Paolo --- Paolo Giannozzi, Democritos and University of Udine, Italy
[Pw_forum] PWscf and highly parallel machines
On Feb 14, 2007, at 10:39 , Alain Allouche wrote: > I wonder if somebody have the experience of PW codes > running on highly parallel machines like in those of the DEISA > supercomputing grid, are the codes like pw.x supporting > such an environment ? they have to, since I am involved in a DEISA project that will use pw.x :-) .Support for very large calculations with pw.x is less mature than for the Car-Parrinello code, which on test run has reached 4000 processors or so. With PW codes some work will be needed in order to perform really large calculations (notably, reduction of nonscalable memory usage and of nonparallel parts of the code) but it will be done. Paolo --- Paolo Giannozzi, Democritos and University of Udine, Italy
[Pw_forum] ambiguity in the pw2wannier.f90
Dear developers of Espresso When we compile the pwscf using pathf95 compiler and acml lapack and blas libraries one error and one warning occurs. The error is that the program doe not understand the some of the .dot. and .times. operators in the bfgs_module.f90 these operators are defined in the basic_algebra_routines.f90 and are used in the main routine of the bfgs_module.f90 (USE basic_algebra_routines) but they are not used in the SUBROUTINE gdiis_step() we found that it is necessary to add (USE basic_algebra_routines) command to this subroutine. The warning is related to the pw2wannier.f90 code in which the subroutine "find_mp_grid" is defined without any argument and parenthesis but it is called with two argument : CALL find_mp_grid(kpt_latt,mp_grid(3)) During compilation a warning message appears due this inconsistency. Could this problem lead to any wrong result during the use of this code (pw2wannier.f90). Javad Hashemifar == Seyed Javad Hashemifar,Ph.D. [current:] Tel:+49-203-3794743Fax:+49-203-3794742 Fachbereich Physik (AG Kratzer), Universitat Duisburg-Essen 47048 Dusiburg, Germany [permanent:] Tel: +98-311-3912375 Fax: +98-311-3912376 Physics Department, Isfahan University of Technology 84156 Isfahan, Iran ---
[Pw_forum] Bulk chemical potential
Dear PWScf users, Could you please suggest me as to how I can calculate the bulk chemical potential of a solid (say, for example, to get bulk chemical potential for gold as -4.401 eV), using the PWScf code? What changes I need to make in the input file? Best regards, Sen
[Pw_forum] PWscf and highly parallel machines
If one were to use CP across such a large number of processors, what algorithm is your best bet for minimizing your electronic d.o.f., sd or cg On 2/14/07, Paolo Giannozzi wrote: > > On Feb 14, 2007, at 10:39 , Alain Allouche wrote: > > > I wonder if somebody have the experience of PW codes > > running on highly parallel machines like in those of the DEISA > > supercomputing grid, are the codes like pw.x supporting > > such an environment ? > > they have to, since I am involved in a DEISA project that > will use pw.x :-) .Support for very large calculations with > pw.x is less mature than for the Car-Parrinello code, which > on test run has reached 4000 processors or so. With PW > codes some work will be needed in order to perform really > large calculations (notably, reduction of nonscalable memory > usage and of nonparallel parts of the code) but it will be > done. > > Paolo > --- > Paolo Giannozzi, Democritos and University of Udine, Italy > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Nichols A. Romero, Ph.D. 1613 Denise Dr. Apt. D Forest Hill, MD 21050 443-567-8328 (C) 410-306-0709 (O) -- next part -- An HTML attachment was scrubbed... URL: /pipermail/attachments/20070214/23ae49ff/attachment.htm
[Pw_forum] Bulk chemical potential
It depends what is your reference gold reservoir. If it is the gold atoms in the gas phase the bulk chemical potential of a metal is its coheive energy: the energy needed to extract an atom from the bulk and bring it to infinite distance. Therefore in practice it is the energy difference between the energy per atom in bulk gold and the energy of an isolated gold atom in a large enough cell. If your reference system is the most stable form of gold (i.e. the bulk) its chemical potential is zero by definition. stefano A SEN wrote: >Dear PWScf users, > Could you please suggest me as to how I can calculate >the bulk chemical potential of a solid (say, for >example, to get bulk chemical potential for gold as >-4.401 eV), using the PWScf code? What changes I need to >make in the input file? > >Best regards, >Sen > >___ >Pw_forum mailing list >Pw_forum at pwscf.org >http://www.democritos.it/mailman/listinfo/pw_forum > >
[Pw_forum] PWscf and highly parallel machines
I wonder if somebody have the experience of PW codes running on highly parallel machines like in those of the DEISA supercomputing grid, are the codes like pw.x supporting such an environment ? Thanks a lot
