[Pw_forum] Difference in Total energies!

[Stefano Baroni]

Dear Bala,

the small energy difference is compatible with the different symmetry that you report. The latter may be due (others may confirm or deny) to a greater tolerance of recent versions of qe to a too small number of decimal digits with which atomic positions are given in input. You may want to increase this number and see if the discrepancies persist. If they do, form yourself an idea of which symmetry is correct and revert to us with an input for your calculation, without which it is very difficult to assist you.

Hope this helps.

SB

On Dec 6, 2012, at 3:55 AM, Balaji Ramanujam wrote:

> Dear QE users:
> 
> I am finding a difference in the Final energy of the same atomic configuration run for a relax calculation on two difference version of QE (5.0.2 and 4.2.1).
> 
> The values are 
> a) in case of QE 5.0.2  --> Final energy   =    -671.7960117280 Ry
> b) in case of QE 4.2.1  --> Final energy   =    -671.7960095330 Ry
> 
> To my surprise, there is a change in the symmetry guess and which is reflected in the # of K-points (19 for 5.0.2 and 10 for 4.2.1) predicted.
> 
> I would like your suggestion in taking the reliable results from these two.
> 
> Thanks 
> Bala
> 
> -- 
> Balaji Ramanujam
> Postdoctoral Research Fellow
> Physics Department
> Boise State University
> Boise, Idaho
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---
Stefano Baroni -  http://stefano.baroni.me, stefanobaroni (skype)
on leave of absence from SISSA, Trieste, presently at the Department of Materials, EPF Lausanne (untill March 2013)

I believe in the despotism of human life and happiness against the liberty of money and possessions - John Steinbeck





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