[Pw_forum] constraints

[Guido Roma]

Dear All,

I have been using contrained relaxations with older version of PWSCF,
I've seen that in version 3.1 many things are changed in that respect.
The module coping with constraints seems to allow only certain types of
constraints (distances, angles), not center of mass type constraints for
examples, and is not any more so easy to write one's own constrain.f90
subroutine. But, further more, I don't understand if the allowed
constraints as specified in the CONSTRAINTS input card are working or
not. Looking at the code I have the impression that they should work if
relaxing by damped dynamics (ion_dynamics='damp'), but not with bfgs.
Can someone confirm this or tell me if and where I'm wrong? 
Any don't see any hint in the user-guide.

Guido
-- 
Guido Roma <roma${at}cea.fr> -- CEA-Saclay - DEN/DMN/SRMP Bat.520/130
Phone: [+33]-1-69085738 -- Fax: ...6867 -- Mobile: [+33]-6-20069085