[gmx-users] mdrun running without simulating new steps

st y1gao at ucsd.edu
Wed Sep 9 20:05:33 CEST 2009


Hi,

I now minimized the energy before the mdrun, and still got the same problem. 
I also tried several other things:
1. I mdrun the system without water, it runs fine. But once I added water, 
it stops propagating steps/files while still seems running.
2. The system has nonzero charge of 0.9, and the Coulomb energy seems (very 
high) the major contribution to the total energy.
Any suggestion will be appreciated!

below is the output of a recent try:
____________________________________________________________________________________________________________________________________________________________________
Input Parameters:
   integrator           = md
   nsteps               = 40000
   init_step            = 0
   ns_type              = Grid
   nstlist              = 1
   ndelta               = 2
   nstcomm              = 1
   comm_mode            = Linear
   nstlog               = 100
   nstxout              = 100
   nstvout              = 100
   nstfout              = 100
   nstenergy            = 100
   nstxtcout            = 100
   init_t               = 0
   delta_t              = 0.0005
   xtcprec              = 1e+06
   nkx                  = 50
   nky                  = 50
   nkz                  = 80
   pme_order            = 4
   ewald_rtol           = 1e-05
   ewald_geometry       = 0
   epsilon_surface      = 0
   optimize_fft         = TRUE
   ePBC                 = xyz
   bPeriodicMols        = FALSE
   bContinuation        = FALSE
   bShakeSOR            = FALSE
   etc                  = Nose-Hoover
   epc                  = No
   epctype              = Isotropic
   tau_p                = 1
   ref_p (3x3):
      ref_p[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
      ref_p[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
      ref_p[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
   compress (3x3):
      compress[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
      compress[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
      compress[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
   refcoord_scaling     = No
   posres_com (3):
      posres_com[0]= 0.00000e+00
      posres_com[1]= 0.00000e+00
      posres_com[2]= 0.00000e+00
   posres_comB (3):
      posres_comB[0]= 0.00000e+00
      posres_comB[1]= 0.00000e+00
      posres_comB[2]= 0.00000e+00
   andersen_seed        = 815131
   rlist                = 1
   rtpi                 = 0.05
   coulombtype          = PME
   rcoulomb_switch      = 0
   rcoulomb             = 1
   vdwtype              = Cut-off
   rvdw_switch          = 0
   rvdw                 = 1
   epsilon_r            = 1
   epsilon_rf           = 1
   tabext               = 1
   implicit_solvent     = No
   gb_algorithm         = Still
   gb_epsilon_solvent   = 80
   nstgbradii           = 1
   rgbradii             = 2
   gb_saltconc          = 0
   gb_obc_alpha         = 1
   gb_obc_beta          = 0.8
   gb_obc_gamma         = 4.85
   sa_surface_tension   = 2.092
   DispCorr             = No
   free_energy          = no
   init_lambda          = 0
   sc_alpha             = 0
   sc_power             = 0
   sc_sigma             = 0.3
   delta_lambda         = 0
   nwall                = 0
   wall_type            = 9-3
   wall_atomtype[0]     = -1
   wall_atomtype[1]     = -1
   wall_density[0]      = 0
   wall_density[1]      = 0
   wall_ewald_zfac      = 3
   pull                 = no
   disre                = No
   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
   em_stepsize          = 0.01
   em_tol               = 10
   niter                = 20
   fc_stepsize          = 0
   nstcgsteep           = 1000
   nbfgscorr            = 10
   ConstAlg             = Lincs
   shake_tol            = 0.0001
   lincs_order          = 4
   lincs_warnangle      = 30
   lincs_iter           = 1
   bd_fric              = 0
   ld_seed              = 1993
   cos_accel            = 0
   deform (3x3):
      deform[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
      deform[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
      deform[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
   userint1             = 0
   userint2             = 0
   userint3             = 0
   userint4             = 0
   userreal1            = 0
   userreal2            = 0
   userreal3            = 0
   userreal4            = 0
grpopts:
   nrdf:       59322
   ref_t:         300
   tau_t:         0.5
anneal:          No
ann_npoints:           0
   acc:	           0           0           0
   nfreeze:           N           N           N
   energygrp_flags[  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
   bQMMM                = FALSE
   QMconstraints        = 0
   QMMMscheme           = 0
   scalefactor          = 1
qm_opts:
   ngQM                 = 0
Table routines are used for coulomb: TRUE
Table routines are used for vdw:     FALSE
Will do PME sum in reciprocal space.

++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
U. Essman, L. Perela, M. L. Berkowitz, T. Darden, H. Lee and L. G. Pedersen
A smooth particle mesh Ewald method
J. Chem. Phys. 103 (1995) pp. 8577-8592
-------- -------- --- Thank You --- -------- --------

Using a Gaussian width (1/beta) of 0.320163 nm for Ewald
Cut-off's:   NS: 1   Coulomb: 1   LJ: 1
System total charge: -0.900
Generated table with 4000 data points for Ewald.
Tabscale = 2000 points/nm
Generated table with 4000 data points for LJ6.
Tabscale = 2000 points/nm
Generated table with 4000 data points for LJ12.
Tabscale = 2000 points/nm

Enabling SPC water optimization for 6481 molecules.

Configuring nonbonded kernels...
Testing ia32 SSE2 support... present.


Removing pbc first time
Center of mass motion removal mode is Linear
We have the following groups for center of mass motion removal:
  0:  rest
There are: 19775 Atoms
Max number of connections per atom is 37
Total number of connections is 53706
Max number of graph edges per atom is 4
Total number of graph edges is 26788
Initial temperature: 0 K

Started mdrun on node 0 Wed Sep  9 10:52:42 2009

           Step           Time         Lambda
              0        0.00000        0.00000

Grid: 8 x 8 x 12 cells
   Energies (kJ/mol)
           Bond          Morse          Angle       G96Angle    Proper Dih.
    3.89303e+02    1.05091e+01    6.55879e+01    7.38907e+00    1.17177e+03
 Ryckaert-Bell.        LJ (SR)   Coulomb (SR)   Coul. recip.      Potential
   -3.77214e+00    2.37518e+01   -2.87848e+05   -2.00200e+04   -3.06203e+05
    Kinetic En.   Total Energy  Conserved En.    Temperature Pressure (bar)
    6.24804e+02   -3.05578e+05   -3.05578e+05    2.53350e+00   -8.53815e+03
________________________________________________________________________________________________________________________________________________________


--------------------------------------------------
From: "Justin A. Lemkul" <jalemkul at vt.edu>
Sent: Tuesday, September 01, 2009 4:35 PM
To: "Discussion list for GROMACS users" <gmx-users at gromacs.org>
Subject: Re: [gmx-users] mdrun running without simulating new steps

>
>
> st wrote:
>> Hi,
>>  I run a two-molecule system with mdrun_d in a water box (~10000 water 
>> molecules.)
>> The program looks running properly (no errors nor warnnings)
>> However the program seems stop outputting files (because the output file 
>> size stop increases) after about 5min.
>> The mdrun_d interface looks normal without any errors, the md.log 
>> contains only two saves:
>
> <snip>
>
>> Grid: 9 x 9 x 14 cells
>>    Energies (kJ/mol)
>>            Bond          Morse          Angle       G96Angle    Proper 
>> Dih.
>>     3.35232e+05    3.27635e+01    7.09937e+02    1.73811e+01 
>> 2.47097e+03
>>         LJ (SR)   Coulomb (SR)   Coul. recip.      Potential    Kinetic 
>> En.
>>     1.48669e+05   -4.50390e+05   -1.89304e+04    1.78117e+04 
>> 4.38796e+05
>>    Total Energy  Conserved En.    Temperature Pressure (bar)
>>     4.56608e+05    4.56608e+05    1.09892e+03   -5.74950e+04
>>  Step           Time         Lambda
>>             100        0.05000        0.00000
>>  Energies (kJ/mol)
>>            Bond          Morse          Angle       G96Angle    Proper 
>> Dih.
>>     3.38536e+05    1.06967e+03    2.21584e+04    4.26526e+01 
>> 3.13457e+03
>>         LJ (SR)   Coulomb (SR)   Coul. recip.      Potential    Kinetic 
>> En.
>>     8.73487e+04   -5.64854e+05   -4.48577e+04   -1.57422e+05 
>> 3.56524e+05
>>    Total Energy  Conserved En.    Temperature Pressure (bar)
>>     1.99102e+05    7.60608e+05    8.92881e+02    7.56563e+04
>>
>
> I'd say the system is exploding.  Your temperature is oscillating between 
> 1000 K and 893 K using a Nose-Hoover thermostat, and your potential starts 
> off in excess of 10^4 kJ mol^-1.  Did you run any sort of energy 
> minimization or weak-coupling equilibration before this run?
>
> It's odd that mdrun wouldn't give some sort of LINCS warning or write out 
> step*.pdb files right beforehand, though.
>
> -Justin
>
>>  **********************
>>  ------------------------------------------------------------------------
>>
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>
> -- 
> ========================================
>
> Justin A. Lemkul
> Ph.D. Candidate
> ICTAS Doctoral Scholar
> Department of Biochemistry
> Virginia Tech
> Blacksburg, VA
> jalemkul[at]vt.edu | (540) 231-9080
> http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>
> ========================================
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