[QE-users] Doubt regarding choice of conv_thr

[Nicola Marzari]

Yes, one should take into account the number of ions or electrons - a 
good starting point for a given system is given by the QE Input 
generator (soon to be updated with our latest refined protocols):

https://www.materialscloud.org/work/tools/qeinputgenerator

				nicola


On 19/09/2024 17:09, Vinay Maithani wrote:
> Dear Quantum Espresso community,
> 
> How to select an appropriate*etot_conv_thr* and *conv_thr* given that 
> these are extensive quantities?
> 
> Since etot_conv_thr represents the total energy convergence threshold 
> for ionic minimization and is extensive, does this value depend on the 
> system size? Should we scale it according to the system size, or can a 
> fixed threshold (e.g., 1.0D-4) be used consistently for both small and 
> large systems? *How does one decide on the appropriate convergence 
> criteria*, and will it differ based on system complexity?
> Can we use thresholds for these quantities arbitrarily very small or large?
> 
> Thank you for your time and guidance.
> -- 
> Regards,
> Vinay Maithani
> MME, IIT Kharagpur
> 
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, SNSF
Head, Laboratory for Materials Simulations, Paul Scherrer Institut
Contact info and websites at http://theossrv1.epfl.ch/Main/Contact