[QE-users] Phonon calculations with different parallelization

[Paolo Giannozzi]

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