[gmx-users] print out the velocities and forces using template.c

[friendli]

Dear all users,

A silly question:

I want to print out the velocities and forces in the trajectories using 
template.c.

In template.c, the coordinates of atom n is in fr.x[n][XX].
Reading the trx.h, i see the x,v and f are defined in the same way. So I 
just change it to fr.v[n][XX] for velocities and fr.f[n][XX] for forces.

but it actually not work with "handle_exceptions: Error while dumping 
state" errors.

Would anybody tell me how to use the forces and velocities using 
template.c?

thank you

Qiang