On 3/21/24 11:03, Chirantan Pramanik wrote:
The phonon frequencies are not the same
basically, they are. The differences are small (a few cm-1 at most) and
mostly affect low-lying frequencies. Self-consistency is not very tight
(1E-14) and may already explain the observed differences.
Paolo
Regards,
Chirantan
------------------------------------------------------------------------
*From:* Paolo Giannozzi <paolo.gianno...@uniud.it>
*Sent:* Thursday, March 21, 2024 11:34 AM
*To:* Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org>;
Chirantan Pramanik <chirantan.prama...@weizmann.ac.il>
*Subject:* Re: [QE-users] Phonon calculations with different
parallelization
On 3/21/24 03:45, Chirantan Pramanik wrote:
My Phonon calculations provide different frequency values for different
parallelization on the cluster especially for the total number of
processors used. Is itpossible or I am doing something very wrong? As
vibrational frequency is gauge invariat how it can be possible?
Thanks,
Chirantan
It is not possible, with one exception: zero-frequency acoustic modes
that have non-zero frequencies; these can vary a lot, but they are
anyway set to zero by imposing the acoustic sum rule.
It might be a bug, but it is hard to say more without knowing what you
exactly computed on which code version
Paolo
--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
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