[gmx-users] g_energy=> Different Average values?

[Mark Abraham]

Chih-Ying Lin wrote:
> 
> 
> Hi
> After the command,
> g_energy  -f abc.edr -o abc.xvg
> 
> the average values is printed out on the screen.
> Energy 	
> 	Average 	RMSD 	Fluct. 	Drift 	Tot-Drift
> Potential 	
> 	-267323 	375.096 	374.647 	-0.12711 	-63.5543
> Kinetic 	En. 	51901.5 	259.034 	259.015 	-0.02151 	-10.7574
> Total 	Energy 	-215421 	275.52 	274.683 	-0.14862 	-74.3106
> Temperature 	302.825 	1.51136 	1.51125 	-0.00013 	-0.06277
> Pressure 	(bar) 	0.963727 	133.498 	133.335 	0.045602 	22.8012
> Volume 	
> 	221.643 	0.362625 	0.362424 	8.36E-05 	0.041823
> Density 	(SI) 	990.272 	1.62111 	1.6202 	-0.00038 	-0.18852
> 
> 
> 
> 
> but the average values are different than calculation from the 
> instantaneous data in the  abc.xvg
> 
> I sum up all the instantaneous data in the abc.xvg and average them.
> I got different average data as those shown up on the screen after 
> g_energy command.

The average values reported in the .edr file are not necessarily the 
averages of the values in the .edr file. See manual appendix.

Mark