[gmx-users] FEP dEkin/dlambda dG/dl constr. values continuously coming out 0.00000e+00

[sunita gupta]

Hello All,

My earlier error ie. dVpot/dlambda values  coming zero is solved now....
But still two values dEkin/dlambda  dG/dl constr as continously coming zero.
I understand that for free energy calculation only dVpot/dlambda are
required. So, should I ignore these two values and proceed with the
work......or due to any mistake with the parameters these values are coming
zero and are going to hamper the values of dVpot/dlambda?

Any suggestion will be appreciated...

Below is the .mdp file and a short portion of .log file

integrator               = sd
tinit                    = 0
dt                       = 0.002
nsteps                   = 100
nstcomm                  = 1
nstxout                  = 100
nstvout                  = 100
nstfout                  = 100
nstlog                   = 500
nstenergy                = 100
nstxtcout                = 5000
xtc-precision            = 1000
nstlist                  = 10
ns_type                  = grid
energygrps               = protein sol <1>
Tcoupl = v-rescale
tau_t = 0.1 0.1
tc_grps = protein non-protein
ref_t = 300 300
gen_vel = yes
gen_temp  = 300
gen_seed = 173529
pbc                      = xyz
rlist                    = 1.0
;domain-decomposition     = no
coulombtype              = pme
;rcoulomb-switch          = 0
rcoulomb                 = 1.0
epsilon-r                = 1
vdw-type                 = cut-off
; cut-off lengths        =
;rvdw-switch              = 0.8
rvdw                     = 1.4
DispCorr                  = EnerPres
; Spacing for the PME/PPPM FFT grid =
fourierspacing           = 0.1
fourier_nx               = 0
fourier_ny               = 0
fourier_nz               = 0
pme_order                = 6
ewald_rtol               = 1e-06
optimize_fft             = yes
free_energy              = yes
init_lambda              = 0.1
delta_lambda             = 0
sc_alpha                 =0.5
sc-power                 =1.0
sc-sigma                 = 0.3
couple-moltype           = <1>
couple-lambda0           = vdw-q
couple-lambda1           = none
couple-intramol          = no
constraints              = hbonds
constraint-algorithm     = Lincs
unconstrained-start      = no
shake-tol                = 0.0001
lincs-order              = 12
lincs-warnangle          = 30

*log file*

Long Range LJ corr.: <C6> 3.4799e-04
Long Range LJ corr.: Epot   -1326.36, Pres:   -82.3094, Vir:    1326.36
   Energies (kJ/mol)
        G96Bond       G96Angle    Proper Dih.  Improper Dih.          LJ-14
    6.99048e+02    1.65819e+03    1.37665e+03    9.23811e+01    8.08449e+02
     Coulomb-14        LJ (SR)        LJ (LR)  Disper. corr.   Coulomb (SR)
    2.87425e+04    2.11542e+05   -2.40740e+03   -1.32636e+03   -7.62482e+05
   Coul. recip.      Potential    Kinetic En.   Total Energy    Temperature
   -1.12221e+05   -6.33518e+05    1.40404e+05   -4.93114e+05    3.20262e+02
 Pressure (bar)  dVpot/dlambda  dEkin/dlambda  dG/dl constr.  Cons. rmsd ()
    1.22146e+04   -1.29163e+03    0.00000e+00    0.00000e+00    6.13343e-03
 Cons.2 rmsd ()
    6.06182e-03

DD  step 9 load imb.: force 18.9%  pme mesh/force 4.177

DD  step 99 load imb.: force 21.3%  pme mesh/force 2.621

           Step           Time         Lambda
            100        0.20000        0.10000

Writing checkpoint, step 100 at Tue Mar 16 18:43:50 2010

   Energies (kJ/mol)
        G96Bond       G96Angle    Proper Dih.  Improper Dih.          LJ-14
    2.87931e+03    4.71650e+03    2.07540e+03    1.47419e+03    8.73118e+02
     Coulomb-14        LJ (SR)        LJ (LR)  Disper. corr.   Coulomb (SR)
    2.81990e+04    1.19859e+05   -2.41710e+03   -1.32636e+03   -7.79296e+05
   Coul. recip.      Potential    Kinetic En.   Total Energy    Temperature
   -1.25837e+05   -7.48800e+05    1.41221e+05   -6.07580e+05    3.22125e+02
 Pressure (bar)  dVpot/dlambda  dEkin/dlambda  dG/dl constr.  Cons. rmsd ()
   -3.80744e+02    2.05188e+02    0.00000e+00    0.00000e+00    2.31636e-06
 Cons.2 rmsd ()
    2.29249e-06

Regards
Sunita Gupta
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20100316/0e42cddc/attachment.html>