[Wien] About the geometry optimization

[yhzhao]

Dear Prof. Blaha,

I want to optimize a slab structure. At the beginning, everything is ok. 
However, after two steps,

the optimization stopped. Using "grep :FOR case.scf", it can be seen 
much large force still, that is

several hundreds mRy/Bohr. The criterion of the force has been set as 2 
mRy/Bohr.

Can you tell me what's the problem? Thanks a lot.

Regards,

Yonghong Zhao