GROMACS version: 2020.1
GROMACS modification: No
Dear Gromacs Users,
I am just following up on my previous email which unfortunately didn’t get any response. Now everything is moved to forum. I would highly appreciate if any of you can comment on this if you have implemented long-range vdw interaction in any of the version of gromacs.
I am trying to implement PME for vdw interaction for an umbrella sampling simulation containing nanoparticles. There are two nano-particles; one is frozen in its place and the other is allowed to move along z-direction. Below is my pulling .mdp file (at the end of the message). When I run the same system with vdw=cut-off ; I see no issue running in any version of the gromacs.
grompp warning:
unlike previous versions(2019 and before), grompp doesn’t process the topology file unless i exclude the frozen(all-directions) nanoparticle from the comm-grps. Here is the warning after processing the topology.
WARNING 1 [file pull.mdp]:
There are 249 atoms that are frozen along less then 3 dimensions and part
of COMM removal group(s), due to limitations in the code these still
contribute to the mass of the COM along frozen dimensions and therefore
the COMM correction will be too small.
mdrun:
The energy minimization seems to run OK with LJPME which I had issues with previous version of gromacs
For the production run, after running few hundred steps the simulation crashes with following error: Decreasing the step size to 0.5femto second doesn’t lead to anything different.
500000 steps, 500.0 ps.
step 400, will finish Tue May 12 04:14:34 2020
step 482: One or more water molecules can not be settled.
Check for bad contacts and/or reduce the timestep if appropriate.
Wrote pdb files with previous and current coordinates
Primary job terminated normally, but 1 process returned
a non-zero exit code. Per user-direction, the job has been aborted.
mpirun noticed that process rank 0 with PID 0 on node scc-k04 exited on signal 11 (Segmentation fault).
pull.mdp file
integrator = md
tinit = 0
dt = 0.001
nsteps = 500000
comm-mode = Linear
nstcomm = 100
comm-grps = !NP1
emtol = 10
emstep = 0.01
nstlog = 10000
nstcalcenergy = 1000
nstenergy = 1000
nstxout-compressed = 50000
compressed-x-precision = 50000
; This selects the subset of atoms for the compressed
; trajectory file. You can select multiple groups. By
; default, all atoms will be written.
compressed-x-grps =
; Selection of energy groups
energygrps =
; NEIGHBORSEARCHING PARAMETERS
cutoff-scheme = Verlet
nstlist = 10
pbc = xyz
periodic-molecules = no
verlet-buffer-tolerance = 0.005
rlist = 1.2
coulombtype = PME
coulomb-modifier = Potential-shift-Verlet
rcoulomb-switch = 0
rcoulomb = 1.2
epsilon-r = 1
epsilon-rf = 0
vdw-type = PME
vdw-modifier = Potential-shift-Verlet
rvdw-switch = 1
rvdw = 1.2
DispCorr = No
table-extension = 1
energygrp-table =
fourierspacing = 0.12
pme-order = 4
ewald-rtol = 1e-05
ewald-rtol-lj = 0.001
lj-pme-comb-rule = Geometric
ewald-geometry = 3d
epsilon-surface = 0
tcoupl = Nose-hoover; Berendsen
tc-grps = SOL non-water
ref-t = 300 300
tau-t = 1 1
pcoupl = Parrinello-Rahman; Berendsen
pcoupltype = Isotropic
nstpcouple = -1
tau-p = 4
compressibility = 4.5e-05
ref-p = 1
refcoord-scaling = No
gen-vel = no;
gen-temp = 300
gen-seed = -1
constraints = none;
constraint-algorithm = Lincs
continuation = no
Shake-SOR = no
shake-tol = 0.0001
lincs-order = 4
lincs-iter = 1
lincs-warnangle = 30
morse = no
; ENERGY GROUP EXCLUSIONS
; Pairs of energy groups for which all non-bonded interactions are excluded
energygrp-excl =
; COM PULLING
pull = yes
; Cylinder radius for dynamic reaction force groups (nm)
pull-cylinder-r = 1.5
pull-constr-tol = 1e-06
pull-print-com = yes
pull-print-ref-value = yes
pull-print-components = yes
pull-nstxout = 50
pull-nstfout = 50
; Number of pull groups
pull_ngroups = 2
; Number of pull coordinates
pull_ncoords = 1
; Group and coordinate parameters
pull_group1_name = NP1
pull-group1-weights =
pull-group1-pbcatom = 0
pull_group2_name = NP2
pull-group2-weights =
pull-group2-pbcatom = 0
pull_coord1_type = umbrella
pull-coord1-potential-provider =
pull_coord1_geometry = distance
pull_coord1_groups = 1 2
pull_coord1_dim = N N Y
pull-coord1-origin = 0.0 0.0 0.0
pull-coord1-vec = 0.0 0.0 0.0
pull_coord1_start = yes
pull-coord1-init = 0
pull_coord1_rate = 0
pull_coord1_k = 1000
pull-coord1-kB = 1000
; Non-equilibrium MD stuff
acc-grps =
accelerate =
freezegrps = NP1 NP2
freezedim = Y Y Y Y Y N
cos-acceleration = 0
Thank you,
Udaya Dahal