PS, We increased speed with install some external libraries (BLAS, LAPACK, and MPI Lib.), I hope it help to other users. Mohsen
On 5/20/10, mohsen modaresi <modaresi.mohsen at gmail.com> wrote: > Dear Baris > Thanks a lot for your answer. > how many scf steps > "do you perform in these 3 hours? Does your system have some > convergence problems?", It take 12 iteration to perform, And there is > no convergence problem > "This is especially important if you are using a low memory > bandwidth architecture.", I can not understand your hint, We use a P4 > machine with 8 core, I think you say we must use Half of them, Is it > true? > And finally thanks for your answer > Moshen Modaresi > > > On 5/20/10, O. Baris Malcioglu <baris.malcioglu at gmail.com> wrote: >> Dear Mohsen, >> Please notice that you have asked a rather vague question regarding >> performance, >> >> First of all, please notice that since PW is a plane wave code, it is >> not just the number of atoms that determine the "size" of the system. >> You have to take into account the number of plane waves you are using. >> This depends on your cutoffs and simulation supercell. Exaggerating >> the situation unnecessarily, for example putting only an ethane >> molecule in a 500x500x500 Bohr box (even with modest cutoff) will >> result in a system size that will certainly give a hard time to the >> computer you are describing. In the same sense, using very high >> cutoffs will lead to same problem. >> >> Secondly, "3 hours" is not a good enough criteria, how many scf steps >> do you perform in these 3 hours? Does your system have some >> convergence problems? >> >> Finally, 8 cpu is not a good enough identification nowadays, if the >> "cpu" you are mentioning is due to hyper-threading, it is usually >> better if you use only 4, since you waste your precious memory >> bandwidth. This is especially important if you are using a low memory >> bandwidth architecture. >> >> Some general guidelines : >> >> -Make sure that your computer is not using swap, >> -Use architecture dependent acceleration libraries such as MKL. For >> example you can setup fftw 3.x to utilize instruction sets such as >> sse2. >> -If this is a parallel compiler check wall times, how much do you >> loose communicating? >> >> Best, >> Baris >> >> 2010/5/20 Phillip Nyawere <pnyawere at gmail.com>: >>> You need high speed computer. I tried with 96 atoms and it was taking >>> even >>> longer. >>> Success. >>> >>> On Wed, May 12, 2010 at 10:07 PM, mohsen modaresi >>> <modaresi.mohsen at gmail.com> wrote: >>>> >>>> Dear Developers and users, >>>> I run a SCF calculation with 71 atoms on a camputer with 8 cpu and 8GB >>>> RAM, i expect it run in some minutes, But it take 3 hours to run. >>>> Is it regular? >>>> >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> Pw_forum at pwscf.org >>>> http://www.democritos.it/mailman/listinfo/pw_forum >>>> >>> >>> >>> >>> -- >>> Phillip W. Otieno Nyawere, >>> Kabarak University, >>> Dept of Physics & Mathematics, >>> P.O Box Private Bag - 20157, >>> Kabarak, Kenya. >>> Tel +254728342054 >>> pnyawere at gmail.com, potieno at kabarak.ac.ke >>> >>> The battle belongs to the Lord. >>> >>> _______________________________________________ >>> Pw_forum mailing list >>> Pw_forum at pwscf.org >>> http://www.democritos.it/mailman/listinfo/pw_forum >>> >>> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> >
