[gmx-users] Computing energies using g_energy (is -nmol mandatory?)

[André Ferreira]

Hello all,

I am trying to compute total energies of several systems, but I am not 
sure if I am doing it the right way. Until now I simply used the command:

g_energy -f file.edr -s file.tpr -o ener.xvg

But after reading the manual, I found the -nmol (number of molecules in 
your sample) flag. If you are comparing systems formed by the same 
amount of molecules the relative energy is not affected. Still, if I am 
comparing energies of systems with different compositions this flag will 
affect them drastically...

Is this option mandatory?

Thank you very much for your time,
Andre