[gmx-users] Variable force constant in umbrella sampling

Kortzak, Daniel d.kortzak at fz-juelich.de
Fri Feb 13 07:07:30 CET 2015

Dear Chris,

thanks for this information. What you describe is exactly the situation I ran into. I have a very sharp maximum close to the binding site which is not sampled well with a weak force while in bulk the weak force looks fine.


Dear Daniel:

It is perfectly fine to use different force constants for different umbrellas. This is commonly done, for example, when you have a very sharp maximum in your PMF and you need to place a few umbrellas at and near this maximum with very strong force constants in order to get good sampling.


From: gromacs.org_gmx-users-bounces at maillist.sys.kth.se <gromacs.org_gmx-users-bounces at maillist.sys.kth.se> on behalf of Kortzak, Daniel <d.kortzak at fz-juelich.de>
Sent: 12 February 2015 22:58
To: gromacs.org_gmx-users at maillist.sys.kth.se
Subject: [gmx-users] Variable force constant in umbrella sampling

Dear gromacs users,

I have again some question regarding umbrella sampling. Is it ok to use different force constants in the different umbrella runs? So far I only read papers where they keep it constant but for me it could be useful to vary this along the reactioncoordinate.


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