[gmx-users] principal moments of ellipsoid

[lammps lammps]

Hi,

I want to study the shape change of a macromolecule which seems like a
ellipsoid.  So, I need obtain the three principal moments of the molecules.

Is the command of g_gyrate helpful for me? The sum of the three principal
moments should be equal to the <Rg^2>.  However, I used the command g_gyrate
-f traj.gro -s nvt.tpr -n anly.ndx -o shape.xvg -p obtain the Rg and other
three qualities.

It seems that the sum of the last three qualities is not equal to the Rg^2.
Is there something wrong?

-- 
wade
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