Pulling only one group with respect to absolute reference point

User discussions
1

GROMACS version: 2019.6
GROMACS modification: No

Dear all,

in one of my simulations I need to pull only a slab of water with respect to an absolute reference point using pull code. but it keeps raising errors.
here is my pull options.
integrator = md-vv
dt = 0.002
nsteps = 7500000

nstxout = 500
nstvout = 500
nstxout-compressed = 500
nstenergy = 500
nstlog = 500

cutoff-scheme = Verlet
nstlist = 10
ns-type = grid
pbc = xyz

coulombtype = P3M-AD
rcoulomb = 1.0

vdwtype = Cut-off
rvdw = 1.0
DispCorr = EnerPres

tcoupl = nose-hoover
tc-grps = Rock_CW Oil Surf_Water
tau-t = 5.0 5.0 5.0
ref-t = 293.15 293.15 293.15
continuation = yes
constraints = h-bonds

pull = yes
pull-ncoords = 1
pull-group1-name = Water_Pull
pull-coord1-type = constant-force
pull-group1-pbcatom = -1
pull-coord1-geometry = direction
pull-coord1-dim = Y N N
pull-coord1-vec = 1.0 0.0 0.0
pull-coord1-origin = 3.3255 2.8805 6.032
pull-coord1-start = yes
pull-coord1-rate = 0.01
pull-coord1-k = -0.1
pull-coord1-groups = 0 0

But I don’t know what to do.

2

Here is the error.
Identical pull group indices in pull-coord1-groups
when I only set one value for pull-coord1-groups it raises an error to set 2 values for this option.

3

In your : pull_coord1_groups = 0 0 should be something like 0 1