[Pw_forum] phonon parallel calculations
Andrea Dal Corso
dalcorso at sissa.it
Thu Feb 26 09:49:21 CET 2015
The problem is that 'image parallelization' and 'GRID approach' are two
complementary approaches. I think that the two together have not been
tested.
In any case your idea to use only_init and then images is interesting,
but probably will need some tuning.
Andrea
On Thu, 2015-02-26 at 00:44 +0100, Carlo Nervi wrote:
> I did some other test with the "GRID" approach above outlined, and I cannot
> understand where I'm wrong.
> I tried different libraries during the compilation process, but while the
> "normal" phonon calculations runs smoothly (but slower, about 1 hour), the
> "GRID" approach always gave me bad (negative) frequencies (but much faster,
> about 10 minutes). I'm using ecut=60 and erho=480
>
> The phonon results from without using the "-ni 8" approach is:
> freq ( 1) = -0.219517 [THz] = -7.322283 [cm-1]
> freq ( 2) = 0.237288 [THz] = 7.915064 [cm-1]
> freq ( 3) = 0.412515 [THz] = 13.760017 [cm-1]
> freq ( 4) = 0.888921 [THz] = 29.651216 [cm-1]
> freq ( 5) = 1.818322 [THz] = 60.652688 [cm-1]
> freq ( 6) = 3.267016 [THz] = 108.975924 [cm-1]
> freq ( 7) = 3.944444 [THz] = 131.572497 [cm-1]
> freq ( 8) = 13.702502 [THz] = 457.066270 [cm-1]
> freq ( 9) = 15.986666 [THz] = 533.257782 [cm-1]
> freq ( 10) = 21.306349 [THz] = 710.703307 [cm-1]
> freq ( 11) = 29.251729 [THz] = 975.732641 [cm-1]
> freq ( 12) = 31.330252 [THz] = 1045.064724 [cm-1]
> freq ( 13) = 40.094614 [THz] = 1337.412380 [cm-1]
> freq ( 14) = 91.247143 [THz] = 3043.677078 [cm-1]
> freq ( 15) = 94.196285 [THz] = 3142.049865 [cm-1]
>
> If I use the "-ni 8" (GRID) I got:
> freq ( 1) = -14.549865 [THz] = -485.331266 [cm-1]
> freq ( 2) = -10.853880 [THz] = -362.046453 [cm-1]
> freq ( 3) = -9.921965 [THz] = -330.961126 [cm-1]
> freq ( 4) = -9.680609 [THz] = -322.910351 [cm-1]
> freq ( 5) = -9.593462 [THz] = -320.003431 [cm-1]
> freq ( 6) = -9.461406 [THz] = -315.598531 [cm-1]
> freq ( 7) = -8.724432 [THz] = -291.015732 [cm-1]
> freq ( 8) = -4.051543 [THz] = -135.144927 [cm-1]
> freq ( 9) = 8.067478 [THz] = 269.102094 [cm-1]
> freq ( 10) = 19.972800 [THz] = 666.220885 [cm-1]
> freq ( 11) = 29.137064 [THz] = 971.907843 [cm-1]
> freq ( 12) = 30.784477 [THz] = 1026.859612 [cm-1]
> freq ( 13) = 39.868296 [THz] = 1329.863222 [cm-1]
> freq ( 14) = 91.702737 [THz] = 3058.874040 [cm-1]
> freq ( 15) = 94.287387 [THz] = 3145.088688 [cm-1]
>
> A lot of negative frequencies appear and sometimes (with a bigger system) I
> got a ************ in the matdyn file (in this case an error is printed).
> Any idea?
> Anybody else had this kind of problem?
> Thank you,
>
> Carlo
>
> >
> > --
>
> ------------------------------------------------------------
> Prof. Carlo Nervi carlo.nervi at unito.it Tel:+39 0116707507/8
> Fax: +39 0116707855 - Dipartimento di Chimica, via
> P. Giuria 7, 10125 Torino, Italy. http://lem.ch.unito.it/
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--
Andrea Dal Corso Tel. 0039-040-3787428
SISSA, Via Bonomea 265 Fax. 0039-040-3787249
I-34136 Trieste (Italy) e-mail: dalcorso at sissa.it
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