[ase-users] How to constrain "c" vector in slab optimization

[Bernstein, Noam CIV USN NRL (6393) Washington DC (USA)]

> On Mar 19, 2021, at 11:34 AM, Reza Behjatmanesh-Ardakani <reza.b.m.a at gmail.com> wrote:
> 
> Thank you Noam for your valuable information. How about fixing some/all angles for simulation of  phase transitions in bulk systems. It seems that it is difficult to constrain some angles and relax other lattice parameters in ASE.  

Yes - those sorts of constraints cannot be easily implemented at the level of the CellFilter, because it only has access to direct stress/strain tensor elements.  If you need such more general constraints, check out the ASE constraints functionality 
	https://wiki.fysik.dtu.dk/ase/ase/constraints.html
I don't know if it has anything, but that's where it would probably be.