Dear All, While running minimization I imposed the the condition for the minimization as to be converged only at Fmax < 10 . But I got the following
Stepsize too small, or no change in energy. Converged to machine precision, but not to the requested precision Fmax < 10 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) Steepest Descents converged to machine precision in 15318 steps, but did not reach the requested Fmax < 10. Potential Energy = -3.3397742e+06 Maximum force = 9.8232233e+02 on atom 6057 Norm of force = 3.6321018e+00 Then according to the above instruction I increased the stepsize up to 0.5 [ I didn't use any constraint during minimization] but got the same. So do I need to increase the stepsize more or is there other procedure to get to the desired convergence criteria ? The minimization .mdp file is as follows ; 7.3.2 Preprocessing ;define = -DFLEXIBLE ; defines to pass to the preprocessor ; 7.3.3 Run Control integrator = steep ; steepest descents energy minimization nsteps = 100000 ; maximum number of steps to integrate ; 7.3.5 Energy Minimization emtol = 10 ; [kJ/mol/nm] minimization is converged when max force is < emtol emstep = 0.01 ; [nm] initial step-size nstcgsteep = 10 ; freq of performing one steepest descent step ; 7.3.8 Output Control nstxout = 500 ; [steps] freq to write coordinates to trajectory nstvout = 500 ; [steps] freq to write velocities to trajectory nstfout = 500 ; [steps] freq to write forces to trajectory nstlog = 100 ; [steps] freq to write energies to log file nstenergy = 100 ; [steps] freq to write energies to energy file energygrps = System ; group(s) to write to energy file ; 7.3.9 Neighbor Searching nstlist = 1 ; [steps] freq to update neighbor list ns_type = grid ; method of updating neighbor list pbc = xyz ; periodic boundary conditions in all directions rlist = 0.8 ; [nm] cut-off distance for the short-range neighbor list ; 7.3.10 Electrostatics coulombtype = PME ; Particle-Mesh Ewald electrostatics rcoulomb = 0.8 ; [nm] distance for Coulomb cut-off ; 7.3.11 VdW vdwtype = cut-off ; twin-range cut-off with rlist where rvdw >= rlist rvdw = 0.8 ; [nm] distance for LJ cut-off DispCorr = Ener ; apply long range dispersion corrections for energy ; 7.3.13 Ewald fourierspacing = 0.12 ; [nm] grid spacing for FFT grid when using PME pme_order = 4 ; interpolation order for PME, 4 = cubic ewald_rtol = 1e-5 ; relative strength of Ewald-shifted potential at rcoulomb Thanks, Tarak -- gmx-users mailing list [email protected] http://lists.gromacs.org/mailman/listinfo/gmx-users * Only plain text messages are allowed! * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/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/Support/Mailing_Lists
