[ase-users] Constraint dynamics and Lagrange multipliers

[Ask Hjorth Larsen]

Hi,

2017-10-12 16:36 GMT+02:00 Weckman Timo via ase-users
<ase-users at listserv.fysik.dtu.dk>:
> Hi all,
>
> I would like to calculate the average force acting on a constraint in a MD simulation. Is there a simple way to get the Lagrange multipliers for, say, a fixed bond length in each time step of the simulation?

You can do atoms.get_forces(apply_constraint=False)  to get the 'raw'
forces and then compare to the regular ones.  Not sure if that is
quite sufficient for what you want to do.

Best regards
Ask

>
>
> ---------------------
> Timo Weckman
> M. Sc. (Tech.), Doctoral Candidate
> Computational Chemistry, Department of Chemistry
> Aalto University School of Chemical Technology
> P.O. Box 16100, FI-00076 AALTO, Finland
>
> Office Room: C242b
> Tel: +358 50 490 8517
> E-Mail: timo.weckman at aalto.fi
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