http://www.gromacs.org/Documentation/Errors#Stepsize_too_small.2c_or_no_change_in_energy._Converged_to_machine_precision.2c_but_not_to_the_requested_precision
On Tue, 17 Jul. 2018, 11:12 pm neelam wafa, <neelam.w...@gmail.com> wrote: > Hi, > > Dear gromacs users, I am running md simmulation of a protein with a ligand. > i have already done it with the same protein and a different ligand. Now > when i run em md run i get following result. > > Energy minimization has stopped, but the forces have not converged to the > requested precision Fmax < 1000 (which may not be possible for your > system). > It stopped because the algorithm tried to make a new step whose size was > too > small, or there was no change in the energy since last step. Either way, we > regard the minimization as converged to within the available machine > precision, given your starting configuration and EM parameters. > > Double precision normally gives you higher accuracy, but this is often not > needed for preparing to run molecular dynamics. > You might need to increase your constraint accuracy, or turn > off constraints altogether (set constraints = none in mdp file) > > writing lowest energy coordinates. > > Steepest Descents converged to machine precision in 150 steps, > but did not reach the requested Fmax < 1000. > Potential Energy = -9.3659806e+05 > Maximum force = 1.0269271e+04 on atom 4399 > Norm of force = 9.8929054e+01 > > NOTE: 10 % of the run time was spent in pair search, > you might want to increase nstlist (this has no effect on accuracy) > please guide me is it reliable to proceede for simmulation. or there is > something wrong. Is it a sign of system instability? > > looking forward for your cooperation. > > Regards > -- > 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.