[gmx-users] EM comparison

Kushal Seth kushalseth at gmail.com
Tue Apr 25 23:47:00 CEST 2006

Hi all !
I was doing EM for a bilayer. While using the mdp file containing only
the energy minimization terms my energy is minimized  but i get the
following  :

Converged to machine precision,
but not to the requested precision Fmax < 100

Double precision normally gives you higher accuracy.
You might need to increase your constraint accuracy, or turn
off constraints alltogether (set constraints = none in mdp file)

writing lowest energy coordinates.

Steepest Descents converged to machine precision in 111 steps,
but did not reach the requested Fmax < 100.
Potential Energy  = -5.2422903e+05
Maximum force     =  3.8640459e+03 on atom 18141
Norm of force     =  7.6843672e+04

What are the implicationsof Fmax > 100 in my case. Also if i modify
the mdp file and increase the terms to contains the temp and pressure
coupling terms my energy comes out to be the same but at the same time
my Fmax also converges to < 100. WHY SO?
Please comment !
Thanks in ADVANCE.
Kushal Seth

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