[gmx-users] Warning in the em.

Seera Suryanarayana palusoori at gmail.com
Fri Dec 4 10:24:13 CET 2015

Dear Gromacs Users,

After my energy minimization I got the following info. I would like to know
does it mean. I came to know that my em process is not perfect. Kindly tell
me how resolve this problem.

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)

writing lowest energy coordinates.

Steepest Descents converged to machine precision in 2297 steps,
but did not reach the requested Fmax < 1000.
Potential Energy  = -1.8318672e+07
Maximum force     =  2.9344773e+03 on atom 213
Norm of force     =  8.8386917e+00

NOTE: The GPU has >20% more load than the CPU. This imbalance causes
      performance loss, consider using a shorter cut-off and a finer PME

NOTE: 15 % of the run time was spent in pair search,
      you might want to increase nstlist (this has no effect on accuracy)

gcq#384: "I do not believe continuum electrostatics" (Arieh Warshel, Nobel
lecture 2013)

Thanks in Advance

Graduate student

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