[gmx-users] NVE mdp

[Ramachandran G]

Dear gromacs users:
         I am using following mdp file as input for simulating the system
with NVE ensemble. But when i check the 'Total energy',
it doesn't seems to remain constant and keep decreasing. I am also giving
some part of my output. Thanks for your help
Rama

title                = Water box
DEFINE               = -DFLEXIBLE
constraints          = hbonds
constraint_algorithm = shake
integrator         = md
dt                 = 0.001   ;
nsteps             = 1500000  ;
nstcomm            = 100
nstlist            = 10
ns_type            = grid
nstenergy          = 5
nstlog             = 0
nstvout            = 5
nstxout            = 5
nstxtcout         = 0
xtc-precision      = 100
nstfout            = 0
coulombtype        = shift
fourierspacing     = 0.135
pme_order          = 4
vdwtype            = switch
rvdw               = 1.0
rlist              = 1.2
rcoulomb           = 1.0
pbc                = xyz
fourier_nx      = 0.0
fourier_ny      = 0.0
fourier_nz      = 0.0
;Berendsen temperature coupling is on

Tcoupl          = no   ; temperature bath (yes, no)
tau_t           = 0.1
tc-grps         = system
ref_t           = 200

;Berendsen Pressure coupling is on
pcoupl          = no         ; pressure bath (yes, no)
pcoupltype      = isotropic
tau_p           = 0.5
compressibility = 4.5e-05
ref_p           = 1.0

;Generate velocities is on at 300K
gen_vel         = yes       ; generate initial velocities
gen_temp        = 300.0     ; initial temperature
gen_seed        = 173529    ; random seed
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Output:
"Total Energy"
    0.000000  -59821.300781
    0.005000  -59806.011719
    0.010000  -59790.937500
    0.015000  -59799.031250
    0.020000  -59803.445312
    0.025000  -59799.058594
    0.030000  -59803.445312
    0.035000  -59804.835938
    0.040000  -59801.652344
    0.045000  -59803.144531
    0.050000  -59804.605469
    0.055000  -59803.421875
    0.060000  -59806.074219
    0.065000  -59805.125000
    0.070000  -59803.632812
    0.075000  -59805.742188
    0.080000  -59807.140625
    0.085000  -59806.539062
    0.090000  -59806.328125
    0.095000  -59806.949219
    0.100000  -59807.351562
    0.105000  -59806.531250
    0.110000  -59806.894531
    0.115000  -59808.933594
    0.120000  -59808.585938
    0.125000  -59807.019531
    0.130000  -59808.171875
    0.135000  -59809.117188
    0.140000  -59808.242188
    0.145000  -59808.820312
    0.150000  -59808.750000
    0.155000  -59806.507812
    0.160000  -59808.839844
    0.165000  -59810.800781
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20100330/4b49cbb2/attachment.html>