[gmx-users] calculating single atom changes along the trajectory as a measure of distance

[PAVAN PAYGHAN]

Dear Groamcs Users,

I am in need to calculate distance changes for a single atom (same atom)
along the simulation time.
I tried to do so using g_dist by giving input of same atom index group
twice for the calculation, output was in null values, which can not be true.
To my surprise g_dist needs two different groups in order to calculate
distance vs Time changes.
Is there any tool or method available in gromacs for doing such
calculation??

Thanks in advance,