[gmx-users] How the "Fmax" is determined without "emtol" in the mdp file?

[Mark Abraham]

Hi,

There are defaults, and documented online: e.g.
http://manual.gromacs.org/documentation/current/user-guide/mdp-options.html#energy-minimization

Mark

On Fri, Jan 18, 2019 at 2:56 PM ZHANG Cheng <272699575 at qq.com> wrote:

> I am doing an energy minimization in a vacuum condition. There is no
> "emtol" in the mdp file. The energy converges in the end, and tell me "Fmax
> < 10" as shown below. So how this "< 10" is determined?
>
>
> Steepest Descents converged to Fmax < 10 in 4063 steps
> Potential Energy  = -2.3973977e+04
> Maximum force     =  9.8130465e+00 on atom 405
> Norm of force     =  1.5696382e+00
>
>
>
>
>
>
>
> My mdp file is:
>
>
> integrator               = steep
> nsteps                   = 10000
> nstxout                  = 0
> nstfout                  = 0
> nstlog                   = 100
>
>
> cutoff-scheme            = Verlet
> nstlist                  = 20
> ns_type                  = grid
> pbc                      = xyz
> verlet-buffer-tolerance  = 0.005
>
>
> coulombtype              = reaction-field
> rcoulomb                 = 1.1
> epsilon_r                = 15    ; 2.5 (with polarizable water)
> epsilon_rf               = 0
> vdw_type                 = cutoff
> vdw-modifier             = Potential-shift-verlet
> rvdw                     = 1.1
> --
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