Hi, read the wiki or search the mailing list archive http://wiki.gromacs.org/index.php/Errors#Stepsize_too_small.2C_or_no_change_in_energy._Converged_to_machine_precision.2C_but_not_to_the_requested_precision
On Tuesday, 14. August 2007 11:28, [EMAIL PROTECTED] wrote: > Dear staff: > When I do the energy minimization of my system contain a protein, an ATP > and water molecules using mdrun, it stopped at 15 steps, and return this > messege: Steepest Descents: > Tolerance (Fmax) = 1.00000e+00 > Number of steps = 2000 > Step= 0, Dmax= 1.0e-02 nm, Epot= -3.24259e+05 Fmax= 3.22275e+04, atom= > 1264 Step= 14, Dmax= 1.2e-06 nm, Epot= nan Fmax= 2.96890e +04, > atom= 1262 Stepsize too small, or no change in energy. > Converged to machine precision, > but not to the requested precision Fmax < 1 > > Double precision normally gives you higher accuracy. > You might need to increase your constraint accuracy, or turn > off constraints alltogether (set constraints = none in mdp file) > > writing lowest energy coordinates. > > Steepest Descents converged to machine precision in 15 steps, > but did not reach the requested Fmax < 1. > Potential Energy = -3.2425944e+05 > Maximum force = 3.2227543e+04 on atom 1264 > Norm of force = nan > > > what's wrong with it? My .mdp file is: > > integrator = steep ;minimization method > emtol = 1.0 ; stop minimization when max force < 1.0 KJ/mol > nsteps = 2000 ; max step number > nstenergy = 10 ;n step to write energy > nstxtcout = 10 ;n step to write coordinates file > > nstlist = 1 ;the step to update the neighbour step list > ns_type = simple; the method to determine neighbour list > rlist = 1.0 ;cutoff for mak e neighbour list > coulombtype = cutoff ;cutoff for electrostatic force distance > rcoulomb = 1.0 ;long range cutoff for elect. > rvdw = 1.0 ; long range cutoff for vdw > constraints = none ;no constraint > pbc = no ; no periode boundary conditions > > Best wishes! greetings, Florian -- ------------------------------------------------------------------------------- Florian Haberl Computer-Chemie-Centrum Universitaet Erlangen/ Nuernberg Naegelsbachstr 25 D-91052 Erlangen Telephone: +49(0) − 9131 − 85 26581 Mailto: florian.haberl AT chemie.uni-erlangen.de ------------------------------------------------------------------------------- _______________________________________________ gmx-users mailing list gmx-users@gromacs.org http://www.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to [EMAIL PROTECTED] Can't post? Read http://www.gromacs.org/mailing_lists/users.php
