[Wien] Req. info. about case.inso for BiFeO3

[Gavin Abo]

"ERROR: negative position in rstruc" is typically because there is 
something wrong with case.struct file [1].

It commonly happens with hexagonal lattices [2,3].  The cause is 
typically a precision or rounding issue [4,5].

"x patchsymm" can sometimes be used to fix the problem [6].

In WIEN2k 18.2, low tolerance values (tol=1.e-4) are used for 
symmetry/symmetso.  It may be that you have a unique structure that 
leads to problems (it may be that it can be resolved with a higher 
tol=1.e-3) [7].

It is likely that nobody can help further unless you provide the 
case.struct file.

[1] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09907.html
[2] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg06519.html
[3] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg07362.html
[4] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16621.html
[5] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg07074.html
[6] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg07063.html
[7] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg17446.html


On 9/28/2018 12:33 AM, Dr. K. Balamurugan wrote:
> Thanks to Prof. Peter Blaha and Prof. Gavin Abo.
>
> I have tried both your suggestions; besides expecting them to work for 
> me, I faced another problem. After setting up the case.inso file, a 
> run of "xsymmetso" showed the following:
> ================================================================
>  gamma not equal 90
>  gamma not equal 90
> ERROR: negative position in rstruc. Please report
> ================================================================
>
> I tried to understand what it is and how to get out of these by 
> exploring old email conversations; but, I found nearly no perfect 
> help. Please, someone clarify me about this warning/error message.
>
> Thanks
>
> With regards
> K. Balamurugan
> NIT Trichirappalli.