[gmx-users] Mdrun problems

[Farid Sa'Adedin]

Dear GROMACS users,

I have encountered a problem when I try to energy minimise a bilayer that I
created.  When I ran it on grompp no errors were detected.  But when I did
mdrun -v

The simulation starts to run but then after a few steps it brings this error
message:

Stepwise too small (6.10352e-07nm) Converged to the machine precision, but not
to the requested position (1000)

Steepest descent did not converge in 15 steps

Potential Energy = nan
Maximum Force 1.28603e+7

I have tried changing various options on the mdp file but to no avail.

If anyone knows what I can do to rectify the situation it would be most
appreciated.

Farid Sa'adedin