Hi, There is this ancient gromacs page which I guess you already found: http://www.gromacs.org/Documentation/How-tos/Removing_fastest_degrees_of_freedom
Here are a couple of references, the second for using virtual sites for CHARMM lipids: Bjelkmar, P., Larsson, P., Cuendet, M. A., Hess, B. & Lindahl, E. Implementation of the CHARMM force field in GROMACS: Analysis of protein stability effects from correction maps, virtual interaction sites, and water models. Journal of Chemical Theory and Computation 6, 459–466 (2010). Loubet, B., Kopec, W. & Khandelia, H. Accelerating all-atom MD simulations of lipids using a modified virtual-sites technique. Journal of Chemical Theory and Computation 10, 5690–5695 (2014). -- Viveca On Fri, Apr 6, 2018 at 9:51 AM, ABEL Stephane <stephane.a...@cea.fr> wrote: > Hi gmx users, > > I know that it is possible to speed up the simulations by a factor 2 (by > using a larger timestep) in GROMACS with virtual interaction sites. By I do > not find a clear procedure on the web in particular if I use CHARMM. Do you > have any pointers or procedures and examples of mdp files to share with me > > Thanks > > Stéphane > > -- > Gromacs Users mailing list > > * Please search the archive at http://www.gromacs.org/ > Support/Mailing_Lists/GMX-Users_List before posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > send a mail to gmx-users-requ...@gromacs.org. > -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.