[gmx-users] Solventbox equilibration

David van der Spoel spoel at xray.bmc.uu.se
Mon May 22 19:00:59 CEST 2006


Anthony Cruz wrote:
> Hi:
> I have been trying to made a solvent box of methacrylic acid using parameters 
> from PRODRG. I change it to GROMOS96 parameters and use charges from DFT 
> calculation. I do the energy minimization with out any problem.  I run a 2ns 
> MD (NVT) with out any problem too.  But when I try to run an MD (NPT) the 
> process end with errors:
> 
> 
>                          :-)  G  R  O  M  A  C  S  (-:
> 
>                               S  C  A  M  O  R  G
> 
>                             :-)  VERSION 3.3.1  (-:
> 
> 
>       Written by David van der Spoel, Erik Lindahl, Berk Hess, and others.
>        Copyright (c) 1991-2000, University of Groningen, The Netherlands.
>              Copyright (c) 2001-2006, The GROMACS development team,
>             check out http://www.gromacs.org for more information.
> 
>          This program is free software; you can redistribute it and/or
>           modify it under the terms of the GNU General Public License
>          as published by the Free Software Foundation; either version 2
>              of the License, or (at your option) any later version.
> 
>                                 :-)  mdrun  (-:
> 
> Option     Filename  Type         Description
> ------------------------------------------------------------
>   -s MAA_BOX_MD2_PCOUPL_TPR.tpr  Input        Generic run input: tpr tpb tpa
>                                    xml
>   -o MAA_BOX_MD2_PCOUPL_MV.trr  Output       Full precision trajectory: trr
>                                    trj
>   -x       traj.xtc  Output, Opt. Compressed trajectory (portable xdr format)
>   -c MAA_BOX_MD2_PCOUPL_CONF.gro  Output       Generic structure: gro g96 pdb
>                                    xml
>   -e MAA_BOX_MD2_PCOUPL_ENE.edr  Output       Generic energy: edr ene
>   -g MAA_BOX_MD2_PCOUPL_LOG.log  Output       Log file
> -dgdl      dgdl.xvg  Output, Opt. xvgr/xmgr file
> -field    field.xvg  Output, Opt. xvgr/xmgr file
> -table    table.xvg  Input, Opt.  xvgr/xmgr file
> -tablep  tablep.xvg  Input, Opt.  xvgr/xmgr file
> -rerun    rerun.xtc  Input, Opt.  Generic trajectory: xtc trr trj gro g96 pdb
> -tpi        tpi.xvg  Output, Opt. xvgr/xmgr file
>  -ei        sam.edi  Input, Opt.  ED sampling input
>  -eo        sam.edo  Output, Opt. ED sampling output
>   -j       wham.gct  Input, Opt.  General coupling stuff
>  -jo        bam.gct  Output, Opt. General coupling stuff
> -ffout      gct.xvg  Output, Opt. xvgr/xmgr file
> -devout   deviatie.xvg  Output, Opt. xvgr/xmgr file
> -runav  runaver.xvg  Output, Opt. xvgr/xmgr file
>  -pi       pull.ppa  Input, Opt.  Pull parameters
>  -po    pullout.ppa  Output, Opt. Pull parameters
>  -pd       pull.pdo  Output, Opt. Pull data output
>  -pn       pull.ndx  Input, Opt.  Index file
> -mtx         nm.mtx  Output, Opt. Hessian matrix
>  -dn     dipole.ndx  Output, Opt. Index file
> 
>       Option   Type  Value  Description
> ------------------------------------------------------
>       -[no]h   bool     no  Print help info and quit
>        -nice    int     19  Set the nicelevel
>      -deffnm string         Set the default filename for all file options
>    -[no]xvgr   bool    yes  Add specific codes (legends etc.) in the output
>                             xvg files for the xmgrace program
>          -np    int      1  Number of nodes, must be the same as used for
>                             grompp
>          -nt    int      1  Number of threads to start on each node
>       -[no]v   bool    yes  Be loud and noisy
> -[no]compact   bool    yes  Write a compact log file
> -[no]sepdvdl   bool     no  Write separate V and dVdl terms for each
>                             interaction type and node to the log file(s)
>   -[no]multi   bool     no  Do multiple simulations in parallel (only with
>                             -np > 1)
>      -replex    int      0  Attempt replica exchange every # steps
>      -reseed    int     -1  Seed for replica exchange, -1 is generate a seed
>    -[no]glas   bool     no  Do glass simulation with special long range
>                             corrections
>  -[no]ionize   bool     no  Do a simulation including the effect of an X-Ray
>                             bombardment on your system
> 
> 
> Back Off! I just backed up MAA_BOX_MD2_PCOUPL_LOG.log 
> to ./#MAA_BOX_MD2_PCOUPL_LOG.log.3#
> Getting Loaded...
> Reading file MAA_BOX_MD2_PCOUPL_TPR.tpr, VERSION 3.3.1 (single precision)
> Loaded with Money
> 
> 
> Back Off! I just backed up MAA_BOX_MD2_PCOUPL_ENE.edr 
> to ./#MAA_BOX_MD2_PCOUPL_ENE.edr.3#
> starting mdrun 'METHACRYLIC ACID BOX 200 MOLECULES'
> 3000000 steps,   3000.0 ps.
> 
> 
> Back Off! I just backed up MAA_BOX_MD2_PCOUPL_MV.trr 
> to ./#MAA_BOX_MD2_PCOUPL_MV.trr.3#
> step 0
> Step 10  Warning: pressure scaling more than 1%, mu: 1.01929 1.01929 1.01929
> step 10, will finish at Thu May 25 15:12:22 2006
> Step 12  Warning: pressure scaling more than 1%, mu: 0.950214 0.950214 
> 0.950214
> 
> Step 13  Warning: pressure scaling more than 1%, mu: 1.06328 1.06328 1.06328
> 
> Step 14  Warning: pressure scaling more than 1%, mu: 1.12283 1.12283 1.12283
> 
> Step 15  Warning: pressure scaling more than 1%, mu: 0.75477 0.75477 0.75477
> 
> Step 16  Warning: pressure scaling more than 1%, mu: 0.904104 0.904104 
> 0.904104
> 
> Step 17  Warning: pressure scaling more than 1%, mu: 2.56873 2.56873 2.56873
> Warning: 1-4 interaction between 99 and 104 at distance 1.007 which is larger 
> than the 1-4 table size 1.000 nm
> These are ignored for the rest of the simulation
> This usually means your system is exploding,
> if not, you should increase table-extension in your mdp file
> 
> Step 18  Warning: pressure scaling more than 1%, mu: 0.623727 0.623727 
> 0.623727
> 
> Step 18, time 0.018 (ps)  LINCS WARNING
> relative constraint deviation after LINCS:
> max 2.910071 (between atoms 356 and 357) rms 1.093812
> bonds that rotated more than 30 degrees:
>  atom 1 atom 2  angle  previous, current, constraint length
>       1      2   53.1    0.3937   0.1793      0.1530
>       2      3   50.9    0.3578   0.1601      0.1390
>       4      5   58.1    0.3168   0.0910      0.1230
> ...................
> 
> 
> What could be the problem? How I could resolve it????
check your topology.
use larger tau_p
> 
> 
> Anthony
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-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se
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