[gmx-users] Position Restrain Problem

Andrea C. Vaiana vaiana at lanl.gov
Mon Dec 19 22:01:09 CET 2005


I had a similar problem and it turned out that in my coordinate file  
atoms were ordered differently than in the topology file...
check if grompp gives a warning when reading in the topology and  
coordinates.
Andrea




On Dec 19, 2005, at 1:08 PM, Anthony Cruz wrote:

> Hi users:
> I am trying to run a simulation of the interaction between a  
> protein that have
> two units and a small peptide. First I have the pdb file of the  
> protein (2
> subunits) and the peptide. I use the -merge option of pdb2gmx to  
> merge the
> two protein subunits in one topology and the peptide in other  
> topology but
> all in the same .gro. I run the energy minimization without problem  
> but it
> end too rapidly:
>
>  Energies (kJ/mol)
>         G96Bond       G96Angle    Proper Dih.  Improper  
> Dih.          LJ-14
>     5.04580e+02    1.64344e+03    1.89068e+03    2.77582e+02     
> 2.00071e+03
>      Coulomb-14        LJ (SR)        LJ (LR)   Coulomb (SR)    
> Coulomb (LR)
>     4.12043e+04    7.06859e+05   -1.90071e+04   -4.29975e+06    
> -4.75686e+05
>       Potential    Kinetic En.   Total Energy    Temperature  
> Pressure (bar)
>    -4.04006e+06    0.00000e+00    0.00000e+00    0.00000e+00     
> 0.00000e+00
>
>            Step           Time         Lambda
>              27       27.00000        0.00000
>
>            Step           Time         Lambda
>              28       28.00000        0.00000
>
>            Step           Time         Lambda
>              29       29.00000        0.00000
>
>
> Stepsize too small, or no change in energy.
> Converged to machine precision,
> but not to the requested precision Fmax < 100
>
> Double precision normally gives you higher accuracy.
> You might need to increase your constraint accuracy, or turn
> off constraints alltogether (set constraints = none in mdp file)
>
> Steepest Descents converged to machine precision in 30 steps,
> but did not reach the requested Fmax < 100.
> Potential Energy  = -4.0400605e+06
> Maximum force     =  2.5371721e+03 on atom 195774
> Norm of force     =  5.4543950e+05
>
> When I try to run the position restrain dynamics the process end  
> abruptly.
> With this output from the log file :
>
> Initializing LINear Constraint Solver
>   number of constraints is 3992
>   average number of constraints coupled to one constraint is 2.9
>
>    Rel. Constraint Deviation:  Max    between atoms     RMS
>        Before LINCS         0.040178   2221   2222   0.006943
>         After LINCS         0.000491   1144   1146   0.000052
>
> Going to use C-settle (4728 waters)
> wo = 0.888096, wh =0.0559521, wohh = 18.0154, rc = 0.081665, ra =  
> 0.00645837
> rb = 0.051255, rc2 = 0.16333, rone = 1, dHH = 0.16333, dOH = 0.1
>
> Constraining the coordinates at t0-dt (step -1)
>    Rel. Constraint Deviation:  Max    between atoms     RMS
>        Before LINCS         0.093162   2933   2934   0.016557
>         After LINCS         0.000218   1271   1273   0.000034
>
> Started mdrun on node 0 Mon Dec 19 09:31:45 2005
> Initial temperature: 298.48 K
>            Step           Time         Lambda
>               0        0.00000        0.00000
>
> Grid: 20 x 20 x 20 cells
>    Rel. Constraint Deviation:  Max    between atoms     RMS
>        Before LINCS         0.066290   2460   2461   0.005114
>         After LINCS         0.000133   1144   1146   0.000015
>
>    Energies (kJ/mol)
>        G96Angle    Proper Dih.  Improper Dih.          LJ-14      
> Coulomb-14
>     2.01626e+03    1.90234e+03    3.07489e+02    2.05943e+03     
> 4.13328e+04
>         LJ (SR)        LJ (LR)   Coulomb (SR)   Coulomb (LR)  
> Position Rest.
>     7.08229e+05   -1.90024e+04   -4.30085e+06   -5.03389e+05     
> 1.49338e+06
>       Potential    Kinetic En.   Total Energy    Temperature  
> Pressure (bar)
>    -2.57402e+06    7.21568e+05   -1.85245e+06    2.99867e+02    
> -1.16469e+03
>
>
> t = 0.020 ps: Water molecule starting at atom 3923 can not be settled.
> Check for bad contacts and/or reduce the timestep.Wrote pdb files with
> previous and current coordinates
>
> t = 0.036 ps: Water molecule starting at atom 7658 can not be settled.
> Check for bad contacts and/or reduce the timestep.Wrote pdb files with
> previous and current coordinates
>
> t = 0.038 ps: Water molecule starting at atom 7703 can not be settled.
> Check for bad contacts and/or reduce the timestep.Wrote pdb files with
> previous and current coordinates
>
> t = 0.040 ps: Water molecule starting at atom 8420 can not be settled.
> Check for bad contacts and/or reduce the timestep.Wrote pdb files with
> previous and current coordinates
>
> t = 0.042 ps: Water molecule starting at atom 7724 can not be settled.
> Check for bad contacts and/or reduce the timestep.Wrote pdb files with
> previous and current coordinates
>
>
> And the following output from the pbs errors file:
>
> starting mdrun 'HLA CLASS II HISTOCOMPATIBILITY ANTIGEN, DR'
> 300000 steps,    600.0 ps.
>
> step 0
> Wrote pdb files with previous and current coordinates
> step 10, will finish at Wed May 31 14:12:32 2006
> Wrote pdb files with previous and current coordinates
>
> Back Off! I just backed up step17.pdb to ./#step17.pdb.1#
> Wrote pdb files with previous and current coordinates
>
> Back Off! I just backed up step18.pdb to ./#step18.pdb.1#
> Sorry couldn't backup step18.pdb to ./#step18.pdb.1#
>
> Back Off! I just backed up step19.pdb to ./#step19.pdb.1#
> Wrote pdb files with previous and current coordinates
> Wrote pdb files with previous and current coordinates
>
> Back Off! I just backed up step19.pdb to ./#step19.pdb.2#
> Wrote pdb files with previous and current coordinates
> step 20, will finish at Sat Apr  7 06:34:59 2007
>
> Back Off! I just backed up step20.pdb to ./#step20.pdb.1#
> Sorry couldn't backup step20.pdb to ./#step20.pdb.1#
>
> Back Off! I just backed up step21.pdb to ./#step21.pdb.1#
> Wrote pdb files with previous and current coordinates
> Wrote pdb files with previous and current coordinates
> MPI: On host caffenero.hpcf.upr.edu,
> Program /usr/local/gromacs/ia64-unknown-linux-gnu/bin/mdrun_mpi,  
> Rank 15,
> Process 31770 received signal SIGSEGV(11)
>
>
> MPI: --------stack traceback-------
> sh: line 1: idb: command not found
>
> MPI: -----stack traceback ends-----
> MPI: On host caffenero.hpcf.upr.edu,
> Program /usr/local/gromacs/ia64-unknown-linux-gnu/bin/mdrun_mpi,  
> Rank 15,
> Process 31770: Dumping core on signal SIGSEG
> V(11) into directory /home/acruz/asv.31738
> MPI: MPI_COMM_WORLD rank 15 has terminated without calling  
> MPI_Finalize()
> MPI: aborting job
> MPI: Received signal 11
>
> What could be the problem???
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