[gmx-users] Saving velocities

[pojeda at icp.uni-stuttgart.de]

Hi,

Does anybody knows how to save the velocities of a group of particles
every N time steps without having to write the .trr file for the whole
system? I mean my system has two kinds of molecules say A and water what
I want is to save the velocities for the atoms in the molecule A
every certain number of steps. The .trr file seems to be very big.
Therefore I just want to write the velocities of the molecule A which
is small.

thanks in advance.