[gmx-users] grompp error

[Amali Guruge]

Dear Gromacs users,

I got the following error when I tried to run grompp.
ERROR 1 [file system.top, line 18]:
  ERROR: One of the box lengths is smaller than twice the cut-off length.
  Increase the box size or decrease rlist

I increased the box size and re-tried to run grompp,but it didn't work. The
box size is 20*20*20 nm3. mdp file options are shown in below. Could you
please anyone help me to solve this problem.

Thank you.

; Define can be used to control processes
define          = -DFLEXIBLE

; Parameters describing what to do, when to stop and what to save
integrator    = steep        ; Algorithm (steep = steepest descent
minimization)
emtol        = 1.0        ; Stop minimization when the maximum force < 1.0
kJ/mol
nsteps        = 200        ; Maximum number of (minimization) steps to
perform
nstenergy    = 10        ; Write energies to disk every nstenergy steps
nstcalcenergy    = 10        ; Calculate energy every step
energygrps    = System    ; Which energy group(s) to write to disk
nstxout               = 100  ; Frequency of writing to .trr file


; Parameters describing how to find the neighbors of each atom and how to
calculate the interactions
cutoff-scheme   = Verlet
ns_type        = simple    ; Method to determine neighbor list (simple,
grid)
coulombtype    = cut-off    ; Treatment of long range electrostatic
interactions
rcoulomb    = 1.0        ; long range electrostatic cut-off
rvdw        = 1.0        ; long range Van der Waals cut-off
constraints    = none        ; Bond types to replace by constraints
pbc        = xyz            ; Periodic Boundary Conditions (yes/no)