[gmx-users] Segmentation fault while using external water model

Mark Abraham mark.j.abraham at gmail.com
Fri Feb 19 02:21:22 CET 2016


Hi,

Are these bonds being converted to constraints, like the original message
suggested?

Mark

On Fri, 19 Feb 2016 02:14 Irem Altan <irem.altan at duke.edu> wrote:

> Hi,
>
> I am still having trouble using TIP4P2005. When I start running my MD
> simulation, it “runs” for a minute or so (although it does not start the
> simulation itself), and then crashes with a segmentation fault.
>
> I have (modified) copy of the amber99sb forcefields in my working
> directory, and I have made the following changes:
>
> - added a tip4p2005.itp file with the correct parameters
>   — named OW as OW_tip4p2005 and HW as HW_tip4p2005
> - added the LJ parameters to ffnonbonded.itp:
> OW_tip4p2005 8      16.00    0.0000  A   3.15890e-01  7.74908e-01
>         HW_tip4p2005 1       1.008   0.0000  A   0.00000e+00  0.00000e+00
> - added the new atom types to atomtypes.atp:
>        HW_tip4p2005    1.00080 ; tip4p/2005 HW
>        OW_tip4p2005   16.00000 ; tip4p/2005 OW
> - added the following line to watermodels.dat
>        tip4p2005 TIP4P/2005 tip4p/2005
>
> My system consists of a protein in its unit cell, unstripped of its
> crystal waters. Below is how my topology file looks like (after solvation,
> adding ions, and energy minimization):
>
> ; Include forcefield parameters
> #include "./amber99sb.ff/forcefield.itp"
>
> ; Include chain topologies
> #include "topol_Protein_chain_A.itp"
> #include "topol_Protein_chain_B.itp"
> #include "topol_Other_chain_A2.itp"
> #include "topol_Other_chain_B2.itp"
>
> ; Include water topology
> #include "./amber99sb.ff/tip4p2005.itp"
>
> #ifdef POSRES_WATER
> ; Position restraint for each water oxygen
> [ position_restraints ]
> ;  i funct  fcx        fcy        fcz
>    1    1 1000    1000       1000
> #endif
>
> ; Include topology for ions
> #include "./amber99sb.ff/ions.itp"
> #include "./tip4p2005cw.itp"
>
> [ system ]
> ; Name
> Protein in water
>
> [ molecules ]
> ; Compound        #mols
> Protein_chain_A     1
> Protein_chain_B     1
> Other_chain_A2      1
> Other_chain_B2      1
> HO4                96
> HO4                62
> SOL         5763
> NA               6
> CL               10
>
> where tip4p2005cw.itp is the same file, only with [settles] removed, and
> molname changed to HO4 for labeling purposes.
>
> What could be the problem? (PS, see below for the contents of
> tip4p2005.itp and tip4p2005cw.itp)
>
> Best,
> Irem
>
>
> =======================================================================================================
> tip4p2005.itp (taken from here and slightly modified:
> https://github.com/wesbarnett/trappeua/blob/master/trappeua.ff/tip4p2005.itp
> )
> ————————
>
>  TIP4P/2005 Water Model
>
> ; J. L. F. Abascal and C. Vega, J. Chem. Phys 123 234505 (2005)
> ; http://dx.doi.org/10.1063/1.2121687
>
>
> [ moleculetype ]
> ; molname    nrexcl
>   SOL        2
>
> [ atoms ]
> ; nr type resnr residu atom cgnr charge    mass
>   1  OW_tip4p2005   1     SOL    OW   1     0.0000   15.994
>   2  HW_tip4p2005   1     SOL    HW1  1     0.5564    1.008
>   3  HW_tip4p2005   1     SOL    HW2  1     0.5564    1.008
>   4  MW             1     SOL    MW   1    -1.1128    0.0
>
> #ifndef FLEXIBLE
> [ settles ]
> ; i  funct   doh       dhh
>   1  1       0.09572   0.15139
> #else
> [ bonds ]
> ; i     j     funct   length  force.c.
>   1     2     1       0.09572 502416.0
>   1     3     1       0.09572 502416.0
>
> [ angles ]
> ; i   j   k   funct   angle   force.c.
>   2   1   3   1       104.52  628.02
> #endif
>
> [ exclusions ]
> 1     2     3     4
> 2     1     3     4
> 3     1     2     4
> 4     1     2     3
>
> ; The position of the dummy is computed as follows:
> ;
> ;         O
> ;
> ;         D
> ;
> ;   H           H
> ;
> ; a = b = (1/2) * (distance(OD)  / [ cos (angle(DOH)) * distance(OH) ] )
> ; = (1/2) * (0.01546 nm    / [ cos (52.26 deg)  * 0.09572 nm   ] )
> ; = 0.13193828
> ; Dummy pos x4 = x1 + a*(x2-x1) + b*(x3-x1)
>
> [ virtual_sites3 ]
> ; Vsite from                    funct   a               b
>   4     1 2 3 1 0.13193828 0.13193828
>
>
> ==============
> tip4p2005cw.itp
> ————————
>
> ; TIP4P/2005 Water Model
>
> ; J. L. F. Abascal and C. Vega, J. Chem. Phys 123 234505 (2005)
> ; http://dx.doi.org/10.1063/1.2121687
>
>
> [ moleculetype ]
> ; molname    nrexcl
>   HO4        2
>
> [ atoms ]
> ; nr type resnr residu atom cgnr charge    mass
>   1  OW_tip4p2005   1     SOL    OW   1     0.0000   15.994
>   2  HW_tip4p2005   1     SOL    HW1  1     0.5564    1.008
>   3  HW_tip4p2005   1     SOL    HW2  1     0.5564    1.008
>   4  MW             1     SOL    MW   1    -1.1128    0.0
>
> ;#ifndef FLEXIBLE
> ;[ settles ]
> ; i  funct   doh       dhh
> ;  1  1       0.09572   0.15139
> ;#else
> [ bonds ]
> ; i     j     funct   length  force.c.
>   1     2     1       0.09572 502416.0
>   1     3     1       0.09572 502416.0
>
> [ angles ]
> ; i   j   k   funct   angle   force.c.
>   2   1   3   1       104.52  628.02
> ;#endif
>
> [ exclusions ]
> 1     2     3     4
> 2     1     3     4
> 3     1     2     4
> 4     1     2     3
>
> ; The position of the dummy is computed as follows:
> ;
> ;         O
> ;
> ;         D
> ;
> ;   H           H
> ;
> ; a = b = (1/2) * (distance(OD)  / [ cos (angle(DOH)) * distance(OH) ] )
> ; = (1/2) * (0.01546 nm    / [ cos (52.26 deg)  * 0.09572 nm   ] )
> ; = 0.13193828
> ; Dummy pos x4 = x1 + a*(x2-x1) + b*(x3-x1)
>
> [ virtual_sites3 ]
> ; Vsite from                    funct   a               b
>   4     1 2 3 1 0.13193828 0.13193828
>
> --
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