[gmx-users] Andersen thermostat

[Sai Pooja]

Hi,

I want to use the Andersen Thermostat (not v-rescale). But I get an error
when I try to use it. My mdp file is as below:

title                    =NPT simulation for a 2D WCA system
cpp                      =/lib/cpp

; RUN CONTROL PARAMETERS
integrator               = md
dt                       = 0.0005
nsteps                   = 400

; OUTPUT CONTROL OPTIONS
nstxout                  = 50  ; No output, except for last frame
(coordinates)
nstvout                  = 0    ; No output, except for last frame
(velocities)
nstfout                  = 0    ; No output, except for last frame (forces)
nstlog                   = 100   ; Write every nth step to the log
nstenergy                = 100     ; Write energies at every n step
nstxtcout                = 0     ; Do not write a compressed tr

; NEIGHBORSEARCHING PARAMETERS
nstlist                  = 10
ns-type                  = Grid
pbc                      = xyz
rlist                    = 0.9

; OPTIONS FOR ELECTROSTATICS AND VDW
coulombtype              = Cut-off
rcoulomb                 = 1.1225
vdw-type                 = Cut-off
rvdw                     = 1.1225

; Temperature coupling
tcoupl                   = Andersen
tc-grps                  = ARAR
tau_t                    = 0.1
ref_t                    = 120.2717
andersen_seed            =-1

; Pressure coupling
pcoupl                   = Berendsen
pcoupltype               = semiisotropic
tau-p                    = 0.20 0.20
compressibility          = 1e-5  0   ;Dont know
ref-p                    = 50 0


;Generate velocities for startup run
gen_vel                  =yes
gen_temp                 =120.2717
gen_seed                 =-1

;Constraints
constraints             = all-bonds
constraint_algorithm    = LINCS
lincs_order             = 4
lincs_iter              = 1
lincs_warnangle         = 90
;unconstrained_start    = no
;shake_tol              = 0.0001



Any idea why this would not work?

Pooja

-- 
Quaerendo Invenietis-Seek and you shall discover.
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