[Wien] Different convergences in Non-SP and SP methods

[pieper]

I would argue that you did NOT find a difference between two 
calculations of the same thing. You only told the program to stop early.

If you want to distiguish between states with a difference in energy 
smaller than the default 0.001 Ry, then you have to converge (with 
regard to ALL numeric parameters like RKmax, Emax, k-mesh ...) to a 
smaller energy. The same holds if you want to see if two solutions are 
the same: you can only tell if and that they are the same up to the 
precision you set as convergence criteria. Smaller energy differences 
are not significant - YOU told the program that they are not!


---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 03.01.2017 11:26, schrieb Abderrahmane Reggad:
> Thank you Mr delamora for your reply
> 
> You have got
> 
> a 0.003Ry/Cr difference between Cr ferromagnetic and antiferromagnetic
> structures
> 
> But my problem is that I have found a difference between 2 equivalent
> calculations
> for the same structure: non magnetic
> 
> Best regards
> 
> --
> 
> Mr:
> A.Reggad                                          
> 
> Laboratoire de Génie Physique
> Université Ibn Khaldoun - Tiaret
> 
> Adresse: BP 144 AL ATTAF AIN DEFLA
> Tel: +213(0)561861963
> Algerie
> 
> 
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