Hi Paolo, Lorenzo, Thanks so much for your attention to this matter. I believe this is likely a bug in QE, and have made an issue post in gitlab. https://gitlab.com/QEF/q-e/issues/108
On Tue, Apr 30, 2019 at 3:03 PM Paolo Giannozzi <[email protected]> wrote: > On Tue, Apr 30, 2019 at 2:50 PM Daniel Marchand <[email protected]> > wrote: > >> Thanks again. So for the BFGS output, for whatever reason there is a >> final SCF step, I"m not sure why. >> > > it's explained in the message preceding the final step > > And yes, correct, the damped_dyanmics(n=50) ~= "BFGS"(n=14). >> >> However my concern is that for the "BFGS" the z component of all axis >> changes, which for my use-case is very bad. However, for damp only the z >> component of axis 3 (v3_z) is allowed to relax. Unfortunately, in my use >> case (the one in the attached example) the damp method seems to converge >> much much slower than BFGS. E.g. for the metrics that would affect my needs: >> >> grep -A3 CELL_PARAMETERS pw.out.bfgs <fast convergence in cell shape, but >> we see shifts in the z-component of axis 1 & axis 2, which for my needs is >> very bad> >> grep -A3 CELL_PARAMETERS pw.out.damp_pr <slow convergence in cell shape, >> but we see that the z-component of axis 1 & axis 2 are held fixed, which >> for my needs is very good> >> >> Is there any way to make bfgs hold the z-component of axis 1 & 2 fixed, >> like how we see for the damp_pr example? >> >> Best, >> >> Daniel >> >> On Tue, Apr 30, 2019 at 2:16 PM Lorenzo Paulatto <[email protected]> >> wrote: >> >>> there are several quircks: >>> >>> I see you did not specify ion_dynamics="damp" when doing damped >>> dynamics, I'm not sure what happens of the ions in this case. >>> >>> The "BFGS" output you sent me is contains 14 steps of BFGS optimization, >>> followed by one step of (damped?) molecular dynamics >>> >>> The damped dynamics run stops because it reaches the maximum of 50 >>> iterations (nstep=50) not because it has converged, but the cell it >>> obtains is pretty much identical to the BFGS one >>> >>> hth >>> >>> On 30/04/2019 13:55, Daniel Marchand wrote: >>> > Thanks, Lorenzo, for the rapid response. I have a bit of a concern >>> w.r.t >>> > the z-only relaxation. When I use BFGS the z component of all the axis >>> > are allowed to relax. However, I do not want this, I want only the z >>> > component of axis 3 (v3_z) to be moved, as per the description in the >>> > documentation. This only seems possible with the damp algorithm. Here >>> I >>> > have attached sample input for both the bfgs and damp_pr algorithms >>> > >>> https://drive.google.com/file/d/17Bt8HHL55yG75cba6awvl8E_wo20KDYI/view?usp=sharing. >>> >>> > Perhaps I have one of the settings wrong? >>> > >>> > Best, >>> > >>> > Daniel >>> > >>> > >>> > On Tue, Apr 30, 2019 at 1:07 PM Lorenzo Paulatto <[email protected] >>> > <mailto:[email protected]>> wrote: >>> > >>> > > 1) Is this still the case? When I enable this setting in my own >>> > > calculations (QE v6.3) I see the cell does indeed allow only >>> > > z-relaxation in the cell, but it does so for all the lattice >>> > directions >>> > > rather than just the a_3 lattice direction. >>> > >>> > In general cell_dofree works with BFGS, but it is true that some >>> times >>> > damped dynamics is more reliable. >>> > >>> > I.e. I recently did some relaxations with cell_dofree="shape", as >>> BFGS >>> > was not findign the minimum for some volumes, I just put >>> > cell_dynamics="damp-pr" >>> > ion_dynamics = 'damp' >>> > with everything default. >>> > >>> > cheers >>> > >>> > -- >>> > Lorenzo Paulatto - Paris >>> > _______________________________________________ >>> > Quantum Espresso is supported by MaX >>> > (www.max-centre.eu/quantum-espresso >>> > <http://www.max-centre.eu/quantum-espresso>) >>> > users mailing list [email protected] >>> > <mailto:[email protected]> >>> > https://lists.quantum-espresso.org/mailman/listinfo/users >>> > >>> > >>> > _______________________________________________ >>> > Quantum Espresso is supported by MaX ( >>> www.max-centre.eu/quantum-espresso) >>> > users mailing list [email protected] >>> > https://lists.quantum-espresso.org/mailman/listinfo/users >>> > >>> >>> -- >>> Lorenzo Paulatto - Paris >>> _______________________________________________ >>> Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso >>> ) >>> users mailing list [email protected] >>> https://lists.quantum-espresso.org/mailman/listinfo/users >> >> _______________________________________________ >> Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso) >> users mailing list [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > > -- > Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > _______________________________________________ > Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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