[gmx-users] Stepsize too small.

[Joel DeWitt]

gmx-users:

I've decided to backtrack and test-run EM on a system utilizing the original
PDB file used to construct the monolayer mentioned in my last post.  The
system is a DPPC bilayer composed of 64 lipid molecules and 3846 waters.
Now, when I try to run EM, no matter what parameters I choose in "em.mdp," I
keep getting the following error message (i.e. the simulation bombs):

Stepsize too small (... nm)Converged to machine precision,
but not to the requested precision (...)



Any suggestions on choosing values for "emtol," "emstep" and the number of
steps?



Joel DeWitt
Department of Physics
Oklahoma State University