[gmx-users] The maxwarn fatal errors

[Mark Abraham]

Hi,

Warnings mean your physics is probably broken, unless you can explain why
it isn't. Suggestions for fixing them are in the warnings.

Mark

On Tue., 7 Jan. 2020, 03:39 변진영, <byunjy0614 at gmail.com> wrote:

> Dear everyone, Happy New year!
> I have gone through the Justin Lemku tutorial for Umbrella Sampling.
> During tutorial, When I treid to input the command line:
>   gmx grompp -f md_umbrella.mdp -c npt0.gro -t npt0.cpt -p topol.top -r
> npt0.gro -n index.ndx -o umbrella0.tpr
>
> I have met two warnings and they occured fatal error.:
>   Fatal error:
>   Too many warnings (2).
>    If you are sure all warnings are harmless, use the -maxwarn option.
>
> And the waring is:
>  WARNING 1 [file topol.top, line 56]:
>   The GROMOS force fields have been parametrized with a physically
>   incorrect multiple-time-stepping scheme for a twin-range cut-off. When
>   used with a single-range cut-off (or a correct Trotter
>   multiple-time-stepping scheme), physical properties, such as the density,
>   might differ from the intended values. Since there are researchers
>   actively working on validating GROMOS with modern integrators we have not
>   yet removed the GROMOS force fields, but you should be aware of these
>   issues and check if molecules in your system are affected before
>   proceeding. Further information is available at
>   https://redmine.gromacs.org/issues/2884 , and a longer explanation of
> our
>   decision to remove physically incorrect algorithms can be found at
>   https://doi.org/10.26434/chemrxiv.11474583.v1 .
>
>
> WARNING 2 [file md_umbrella.mdp]:
>   With Nose-Hoover T-coupling and Parrinello-Rahman p-coupling, tau-p (1)
>   should be at least twice as large as tau-t (1) to avoid resonances
>
> I solved this problem with using -maxwarn option but I am wondering
> whether thses warning is passed over.
> What do you think what I happend? dears. Any idea on what caused this
> problem?
> --
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