[gmx-users] What should be standard emtol for mixed lipid system?

[chandra kumar]

Dear All,
I have taken up a system for mixed lipid POPE+POPG+POPC. The bilipid
membrane was created using membuilder tool
http://bioinf.modares.ac.ir/software/mb2/. I tried to run the energy
minimization step with the emtol value < 1000.

I received the following message:
...............................................................................................................
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)

Steepest Descents converged to machine precision in 175 steps,
but did not reach the requested Fmax < 1000.
Potential Energy  = -1.3346176e+06
Maximum force     =  1.2168722e+08 on atom 15675
Norm of force     =  6.3160419e+05
.................................................................................................................
 Is there some specific parameters that could be standard for mixed lipid
system. If yes please suggest.

-- 
Chandra Shekhar Kumar || M.Tech
Research Scholar
Kusuma School of Biological Sciences
Indian Institute of Technology Delhi
Delhi, Pincode:110016
Tel: +911126597517
Mob: +918700377994