[gmx-users] on direction of pull.ppa

[Justin MacCallum]

Hi Xu,

You need to set the pulled group and the reference group, although the
reference group isn't used for anything in the case of AFM pulling. If
you have runtype set to AFM, then the only other parameters that matter
are direction - which specifies which axis to pull along (ie. 0 0 1 is
the z axis), pull rate, which is in nm/timestep, and forceconstant.  The
r0_group* entries are for making starting structures for other types of
pulling.

Cheers,
Justin