[gmx-users] position restraints
lindahl at stanford.edu
Thu Aug 15 21:53:56 CEST 2002
T. Zaraiskaya wrote:
> How to fix the positions of selected atoms during the simulation run
> in GROMACS?
Use freeze groups; it should be explained somewhere in the manual. It's
easy to create groups with the make_ndx program (or manually). Assuming
you want to freeze 'grp1' completely, and 'grp2' in the x and y
directions, you can use these options in the mdp file:
freezegrps = grp1 grp2
freezedim = y y y y y n
The freezedim option has three fields (y or n) for each group,
designating whether x,y & z degrees of freedom should be frozen.
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