[gmx-users] Energy minimization issue

[Khadija Amine]

Dear Gromacs users,

I'm simulation a double chain protein-ligand complex using Amber force
field. I have written parameters and generated the topology.

The energy minimization of the complex gives me the following error:

*Energy minimization has stopped, but the forces have not converged to the*

*requested precision Fmax < 1000 (which may not be possible for your
system).*

*It stopped because the algorithm tried to make a new step whose size was
too*

*small, or there was no change in the energy since last step. Either way,
we*

*regard the minimization as converged to within the available machine*

*precision, given your starting configuration and EM parameters*

*Double precision normally gives you higher accuracy, but this is often not*

*needed for preparing to run molecular dynamics.*

*You might need to increase your constraint accuracy, or turn*

*off constraints altogether (set constraints = none in mdp file)*
Could you please tell me what is the issue and provide some suggestions

Thank you
*Best regards*
*Khadija Amine*
Ph.D. Biology and Health
Biochemistry & Bioinformatics