[gmx-users] Understanding g_energy output in GROMACS 4.5.7

[Justin Lemkul]

On 10/22/14 12:46 PM, Agnivo Gosai wrote:
> Dear Users
>
> This is the output of g_energy command on the em.edr file for my system. I
> ran a preliminary energy minimization following the solvation and ions
> addition of my system.
>
> Last energy frame read 855 time 1080.000
>
> Statistics over 1081 steps [ 0.0000 through 1080.0000 ps ], 1 data sets
> All statistics are over 856 points (frames)
>
> Energy                      Average   Err.Est.       RMSD  Tot-Drift
> -------------------------------------------------------------------------------
> Potential                   -685672      22000    69839.9    -138494
> (kJ/mol)
>
> I am unable to understand the meaning of the term "Err. Est" and
> "Tot-drift". I have consulted the GROMACS manual but I am not satisfied and
> failed to understand the physical significance.
>

The error estimate and drift in potential during energy minimization is 
meaningless.  By definition, the energy changes, often drastically.

-Justin

-- 
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Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441
http://mackerell.umaryland.edu/~jalemkul

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