[gmx-users] Problems with tabulated potentials

[Harry Saavedra]

Dear all;

I ran a simulation using two tabulated potentials for two energy groups but it seems that 
Gromacs is not generating any potential because LJ energies = 0.0000  in every step.

The groups are TET and HS and they are represented in index.ndx. Their tabulated potentials
are table_TET_TET.xvg and table_HS_HS.xvg respectively. The charge of every atom is zero and
the Gromacs version is 3.3.3.

My parameter and md.log files are:

#################### Parameter file ###########################                 
integrator               = sd
dt                       = 0.001
nsteps                   = 100000
nstxout                  = 100
nstvout                  = 100
nstfout                  = 100
nstlog                   = 1000
nstenergy                = 1000
nstxtcout                = 100
xtc_grps                 = System
energygrps               = TET HS
energygrp_table             = TET TET HS HS
energygrp_excl           = TET HS
nstlist                  = 10
ns_type                  = grid
rlist                    = 1.0

coulombtype              = User
rcoulomb                 = 1.0
epsilon_rf               = 80

vdwtype                  = User
rvdw                     = 1.0

tcoupl                   = Berendsen
tc-grps                  = System
tau_t                    = 0.2
ref_t                    = 300

Pcoupl                   = no
tau_p                    = 1.0
compressibility          = 4.46e-5
ref_p                    = 1.0
gen_vel                  = yes
gen_temp                 = 300
gen_seed                 =-1
 ###############################################################

 tables:  table_TET_TET.xvg  &  table_HS_HS.xvg


>mdrun_mpi  -s topol.tpr  -table table.xvg   -x traj -o traj   -g md


########################## md.log file ##########################
.
.
.
Table routines are used for coulomb: TRUE
Table routines are used for vdw:     TRUE
Cut-off's:   NS: 1   Coulomb: 1   LJ: 1
System total charge: 0.000
Read user tables from table_TET_TET.xvg with 12582 data points.
Tabscale = 4838.85 points/nm
Read user tables from table_HS_HS.xvg with 12402 data points.
Tabscale = 4769.62 points/nm
.
.
.

 Step           Time         Lambda
          23000       23.00000        0.00000
   Energies (kJ/mol)
           Bond          Angle        LJ (SR)   Coulomb (SR)      Potential
    4.79413e+03    2.18701e+03    0.00000e+00    0.00000e+00    6.98115e+03
    Kinetic En.   Total Energy    Temperature Pressure (bar)
    1.36561e+04    2.06372e+04    3.04239e+02    7.13050e+01
.
.
.	<====  A V E R A G E S  ====>
	<==  ###############  ======>
.......

    Epot (kJ/mol)        Coul-SR          LJ-SR   
        TET-TET    0.00000e+00    0.00000e+00
         TET-HS    0.00000e+00    0.00000e+00
          HS-HS    0.00000e+00    0.00000e+00
.
.
.
##############################################################


Could you please tell me what is wrong ?


P.S.

even I have tried:

mdrun_mpi  -s topol.tpr  -table table.xvg -tablep table_TET_TET.xvg table_HS_HS.xvg   
-x traj -o traj   -g md

But I got the same result.


Thanks in advance,

Harry G.

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