<div dir="ltr"><div dir="ltr">On Fri, May 24, 2019 at 3:36 PM Lorenzo Paulatto <<a href="mailto:paulatz@gmail.com">paulatz@gmail.com</a>> wrote:<br></div><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">We recently noticed that the BFGS default algorithm does not always <br>
respect the cell_dofree constraint, a fix is in the development verison <br>
of the code but not in the released version.<br></blockquote><div><br></div><div>Should be present in the available patches for v.6.4.1: file <a href="https://github.com/QEF/q-e/releases/download/qe-6.4.1/backports-6.4.1.diff">backports-6.4.1.diff</a> in <a href="https://github.com/QEF/q-e/releases">https://github.com/QEF/q-e/releases</a></div><div><br></div><div>Paolo</div><div><br></div><div> > thank you very much for your answer, i try it.but i set <br>
> cell_dofree='2Dxy' , because i need to fix cell parameter. in z direct.<br>
> <br>
</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
As a workaround you can take the bfgs_module.f90 file from the <br>
development version<br>
<a href="https://gitlab.com/QEF/q-e/raw/develop/Modules/bfgs_module.f90" rel="noreferrer" target="_blank">https://gitlab.com/QEF/q-e/raw/develop/Modules/bfgs_module.f90</a><br>
and overwrite the one you find in Modules// and recompile the code.<br>
<br>
Or you can set<br>
ion_dynamics = 'damp'<br>
and<br>
cell_dynamics = "damp-pr"<br>
which should respect the constraint.<br>
<br>
That said, there is no specific problem to use cell_dofree='ibrav' in <br>
conjunction with another cell_dofree, I just implemented this feature as <br>
a cell_dofree value because of lazyness.<br>
<br>
You can open Modules/cell_base.f90 and at line 84 change<br>
LOGICAL :: enforce_ibrav = .FALSE.! True if ibrav ...<br>
to<br>
LOGICAL :: enforce_ibrav = .TRUE.! True if ibrav ...<br>
(do not forget to recompile pw.x) to use cell_dofree="ibrav" together <br>
with any other cell_dofree<br>
<br>
hth<br>
<br>
-- <br>
Lorenzo Paulatto - Paris<br>
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