[gmx-users] PBC removing why?

JAVIER SACRISTAN jus29 at psu.edu
Mon Aug 15 23:29:01 CEST 2005


Hi Gromacs people,
 
I'm working to perform molecular dynamics simulations of 27 polymer chains in
PBC and I have 
found some problems.
 
After preliminary minimization and equilibration of one chain under PBC and NPT
by means of  trjconv I have extracted the coordinates for my polymer chain ( I
am interested in some specific conformation=specific frame on the trajectory
file).
 
Then with genconf -f  trajout.gro -nbox 3 3 3 -dist 1 -rot -o peo27.gro  I have
built a cell with 27  chains.

 

Finally with 

grompp -f peo25.mdp -p peo25.top -c tpeo25.gro -o peo25.tpr I have generated 
tpr file.

 

But unfortunately when I run the simulation I have got this message on the log
file:

 

Removing PBC first time.

 

I don t understand what is going on? I have already checked Gromacs Users
Mailing list archives, and I have found one mail about PBC errors, but the
answer ( setenv GMXFULLPBC 1) was recommended for  infinite systems /or rings.
In  my case it is a linear polymer.

 

 

I have included the log file.

Any help would be really appreciated.

 

Javier

 

 

Input Parameters:
   integrator           = md
   nsteps               = 500000
   init_step            = 0
   ns_type              = Grid
   nstlist              = 5
   ndelta               = 2
   bDomDecomp           = FALSE
   decomp_dir           = 0
   nstcomm              = 1
   nstcheckpoint        = 1000
   nstlog               = 500
   nstxout              = 1000
   nstvout              = 1000
   nstfout              = 1000
   nstenergy            = 500
   nstxtcout            = 50
   init_t               = 0
   delta_t              = 0.002
   xtcprec              = 1000
   nkx                  = 117
   nky                  = 117
   nkz                  = 117
   pme_order            = 4
   ewald_rtol           = 1e-05
   ewald_geometry       = 0
   epsilon_surface      = 0
   optimize_fft         = FALSE
   ePBC                 = xyz
   bUncStart            = FALSE
   bShakeSOR            = FALSE
   etc                  = Berendsen
   epc                  = Berendsen
   epctype              = Isotropic
   tau_p                = 0.5
   ref_p (3x3):
      ref_p[    0]={ 1.00000e+02,  0.00000e+00,  0.00000e+00}
      ref_p[    1]={ 0.00000e+00,  1.00000e+02,  0.00000e+00}
      ref_p[    2]={ 0.00000e+00,  0.00000e+00,  1.00000e+02}
   compress (3x3):
      compress[    0]={ 4.50000e-05,  0.00000e+00,  0.00000e+00}
      compress[    1]={ 0.00000e+00,  4.50000e-05,  0.00000e+00}
      compress[    2]={ 0.00000e+00,  0.00000e+00,  4.50000e-05}
   andersen_seed        = 815131
   rlist                = 0.9
   coulombtype          = Ewald
   rcoulomb_switch      = 0
   rcoulomb             = 0.9
   vdwtype              = Cut-off
   rvdw_switch          = 0
   rvdw                 = 0.9
   epsilon_r            = 1
   tabext               = 1
   gb_algorithm         = Still
   nstgbradii           = 1
   rgbradii             = 2
   gb_saltconc          = 0
   implicit_solvent     = No
   DispCorr             = EnerPres
   fudgeQQ              = 1
   free_energy          = no
   init_lambda          = 0
   sc_alpha             = 0
   sc_sigma             = 0.3
   delta_lambda         = 0
   disre_weighting      = Conservative
   disre_mixed          = FALSE
   dr_fc                = 1000
   dr_tau               = 0
   nstdisreout          = 100
   orires_fc            = 0
   orires_tau           = 0
   nstorireout          = 100
   dihre-fc             = 1000
   dihre-tau            = 0
   nstdihreout          = 100
   em_stepsize          = 0.01
   em_tol               = 10000
   niter                = 20
   fc_stepsize          = 0
   nstcgsteep           = 1000
   nbfgscorr            = 10
   ConstAlg             = Lincs
   shake_tol            = 1e-04
   lincs_order          = 4
   lincs_warnangle      = 30
   lincs_iter           = 1
   bd_temp              = 300
   bd_fric              = 0
   ld_seed              = 1993
   cos_accel            = 0
   userint1             = 0
   userint2             = 0
   userint3             = 0
   userint4             = 0
   userreal1            = 0
   userreal2            = 0
   userreal3            = 0
   userreal4            = 0
grpopts:
   nrdf:               7449
   ref_t:               450
   tau_t:               0.1
anneal:                  No
ann_npoints:              0
   acc:            0           0           0
   nfreeze:           N           N           N
   energygrp_excl[  0]: 0
   efield-x:
      n = 0
   efield-xt:
      n = 0
   efield-y:
      n = 0
   efield-yt:
      n = 0
   efield-z:
      n = 0
   efield-zt:
      n = 0
CPU=  0, lastcg=  404, targetcg=  202, myshift=    0
nsb->shift =   1, nsb->bshift=  0
Neighbor Search Blocks
nsb->nodeid:         0
nsb->nnodes:      1
nsb->cgtotal:   405
nsb->natoms:   2484
nsb->shift:       1
nsb->bshift:      0
Nodeid   index  homenr  cgload  workload
     0       0    2484     405       405
 
Max number of graph edges per atom is 4
Table routines are used for coulomb: TRUE
Table routines are used for vdw:     FALSE
Using a Gaussian width (1/beta) of 0.288146 nm for Ewald
Cut-off's:   NS: 0.9   Coulomb: 0.9   LJ: 0.9
Generated table with 500 data points for COUL.
Tabscale = 500 points/nm
Generated table with 500 data points for LJ6.
Tabscale = 500 points/nm
Generated table with 500 data points for LJ12.
Tabscale = 500 points/nm
Generated table with 950 data points for Ewald.
Tabscale = 500 points/nm
Generated table with 950 data points for LJ6.
Tabscale = 500 points/nm
Generated table with 950 data points for LJ12.
Tabscale = 500 points/nm
Going to determine what solvent types we have.
There are 27 molecules, 405 charge groups and 2484 atoms
There are 0 optimized solvent molecules on node 0
There are 0 optimized water molecules on node 0
Center of mass motion removal mode is Linear
We have the following groups for center of mass motion removal:
  0:  rest, initial mass: 36495.8
There are: 2484 Atom
Removing pbc first time
Done rmpbc
Started mdrun on node 0 Mon Aug 15 14:50:12 2005
Initial temperature: 449.96 K
           Step           Time         Lambda
              0        0.00000        0.00000
 
Grid: 30 x 30 x 30 cells
There are 2484 atoms in your xtc output selection
 
++++++++ PLEASE CITE THE FOLLOWING REFERENCE ++++++++
H. J. C. Berendsen, J. P. M. Postma, A. DiNola and J. R. Haak
Molecular dynamics with coupling to an external bath
J. Chem. Phys. 81 (1984) pp. 3684-3690
-------- -------- --- Thank You --- -------- --------
 
Large VCM(group rest):     -0.56846,    -13.47183,     -6.20070, ekin-cm: 
4.01932e+06
Long Range LJ corr. to Epot:   -37.0893, Pres:  -0.488348, Vir:    222.536
   Energies (kJ/mol)
        G96Bond       G96Angle    Proper Dih.          LJ-14     Coulomb-14
    3.58014e+03    5.23920e+03    4.07175e+03   -1.37463e+03    9.63356e+03
        LJ (SR)  Disper. corr.   Coulomb (SR)   Coulomb (LR)      Potential
    8.36634e+12   -3.70893e+01   -1.95173e+02   -3.89469e+03    8.36634e+12
    Kinetic En.   Total Energy    Temperature Pressure (bar)
    5.95690e+23    5.95690e+23    1.92360e+22    2.61444e+21
 
 
Step 1  Warning: pressure scaling more than 1%, mu: 1.56867e+14 1.56867e+14
1.56867e+14
Large VCM(group rest): -4140635995634663424.00000, 16562543982538653696.00000,
-8281271991269326848.00000, ekin-cm:          inf
Grid: -2147483648 x -2147483648 x -2147483648 cells
Fatal error: ci = -1 should be in 0 .. -1 [FILE nsgrid.c, LINE 218]
 
 
 
 



 

Javier Sacristan Bermejo
115 Fenske Lab.
Computer Polymer Simulations



More information about the gromacs.org_gmx-users mailing list