[gmx-users] pulldim option in umbrella sampling

[Hwankyu Lee]

Dear gmx-users,

I'm trying to do umbrella sampling with the distance restraint between 
COMs of two helix peptides, and I'm wondering about pulldim and pos1 
options. My ppa file is below.  Do I need to put "pulldim = Y Y Y"?    
My reference_group moves, so the pulled group also moves. In this case, 
how can I make "pos1" option? -------------
verbose = no
runtype = umbrella
group_1 = KID6
pulldim = ??
reference_group = KID5
reftype = com
k1 = 1000
pos1 = ??
-------------

best,
Hwankyu.