[gmx-users] Re: gmx-users Digest, Vol 58, Issue 59

Justin A. Lemkul jalemkul at vt.edu
Wed Feb 11 14:08:44 CET 2009



Robert Fenwick wrote:

> 
> pdb2gmx -f prot1LYD.pdb -ter -ignh -vsite hydrogens -water tip3p
> select OPLS, 0, 0

The benchmarks were done with SPC/E; don't know if that will make a difference 
or not (probably not, but just FYI).

> 
> editconf -f conf.gro -bt dodecahedron -d 0.7 -o box.gro
> 

This box will be smaller than what was described in the paper.  Try -box 7 7 7 
for a more reasonable size (and total number of water molecules).

> genbox -cp box.gro -cs spc216.gro -p topol.top -o solvated.gro
> 
> grompp -f em.mdp -p topol.top -c solvated.gro -o sol.tpr
> 
> genion -s sol.tpr -nn 8 -nname CL- -nq -1 -np 0 -pname NA+ -pq 1 -p
> topol.top -o solvatedIon.gro
> select 12 (SOL)
> 
> grompp -f em.mdp -p topol.top -c solvatedIon.gro -o em.tpr
> 
> mdrun -v -deffnm em
> 
> grompp -f pr.mdp -p topol.top -c em.gro -o pr.tpr
> 
> mpirun -np 16 mdrun_mpi -v -deffnm pr -npme 8
> 

You're bound to get bad performance doing this.  You've got a 1:1 PP:PME ratio. 
  If you've done everything correctly, grompp should estimate that the PME load 
be about 33%, thus 2:1 PP:PME.  I ran this particular benchmark on our cluster 
using 12 nodes, with 4 for PME.

> grompp -f run.mdp -p topol.top -c pr.gro -o run.tpr
> 
> mpirun -np 16 mdrun_mpi -v -deffnm run -npme 8
> 
> The inputs are, and come directly from the article Hess et al., 2008
> JCTC GROMACS 4 :
> 
> ::::::::::::::
> em.mdp
> ::::::::::::::
> integrator      = steep
> nsteps          = 200
> nstlist         = 10
> rlist           = 1.0
> coulombtype     = pme
> fourierspacing  = 0.125
> rcoulomb        = 1.0
> vdw-type        = cut-off
> rvdw            = 1.0
> lincs-order     = 6
> nstenergy       = 10
> ::::::::::::::
> pr.mdp
> ::::::::::::::
> integrator      = md
> nsteps          = 50000
> dt              = 0.002
> nstlist         = 10
> rlist           = 1.0
> coulombtype     = pme
> fourierspacing  = 0.125
> rcoulomb        = 1.0
> vdw-type        = cut-off
> rvdw            = 1.0
> lincs-order     = 6
> tcoupl          = Berendsen
> tc-grps         = protein non-protein
> tau-t           = 0.1 0.1
> ref-t           = 298 298
> Pcoupl          = Berendsen
> tau-p           = 1.0
> compressibility = 1e-5 1e-5 1e-5 0 0 0
> ref-p           = 1.0
> nstenergy       = 100
> define          = -DPOSRES
> 
> ::::::::::::::
> run.mdp
> ::::::::::::::
> integrator      = md
> nsteps          = 50000
> dt              = 0.004
> nstlist         = 5
> rlist           = 1.0
> coulombtype     = pme
> fourierspacing  = 0.125
> rcoulomb        = 1.0
> vdw-type        = cut-off
> rvdw            = 1.0
> lincs-order     = 6
> tcoupl          = Berendsen
> tc-grps         = protein non-protein
> tau-t           = 0.1 0.1
> ref-t           = 298 298
> nstxout         = 1000
> nstvout         = 1000
> nstxtcout       = 100
> nstenergy       = 100
> 

Try applying "constraints = all-bonds" (based on Table 3 of Berk's JCTC paper 
about P-LINCS).

-Justin

> The simulation dies with:
> 
> Step 6, time 0.024 (ps)  LINCS WARNING
> relative constraint deviation after LINCS:
> rms 0.222533, max 1.229818 (between atoms 328 and 329)
> bonds that rotated more than 30 degrees:
>  atom 1 atom 2  angle  previous, current, constraint length
>    1970   1973   90.0    0.2413   0.3543      0.1930
>    1888   1891   65.8    0.4413   0.1879      0.1930
>     447    449   59.2    0.2406   0.1939      0.1939
>     656    660   90.0    0.1930   0.4267      0.1930
>     616    619   90.0    0.1924   0.2612      0.1930
>     477    480   89.9    0.2945   0.3802      0.1930
>     319    329   65.3    0.1670   0.1816      0.1670
>     328    329   90.0    0.0915   0.2039      0.0915
>     762    765   42.4    0.1584   0.1554      0.1583
>     762    766   44.0    0.1581   0.1616      0.1583
> 
> t = 0.024 ps: Water molecule starting at atom 16419 can not be settled.
> Check for bad contacts and/or reduce the timestep.
> Wrote pdb files with previous and current coordinates
> Warning: 1-4 interaction between 949 and 963 at distance 6.212 which
> is larger than the 1-4 table size 2.000 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
> or with user tables increase the table size
> Warning: 1-4 interaction between 747 and 753 at distance 14.118 which
> is larger than the 1-4 table size 2.000 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
> or with user tables increase the table size
> 
> -------------------------------------------------------
> Program mdrun_mpi, VERSION 4.0.3
> Source code file: pme.c, line: 518
> 
> Fatal error:
> 11 particles communicated to PME node 3 are more than a cell length
> out of the domain decomposition cell of their charge group
> -------------------------------------------------------
> 
> 
>> The methodology for the lysozyme benchmark is pretty explicit in the Gromacs 4
>> paper; is there some aspect that is not clear?
> 
> I agree that the paper is clear, I ask because it is obvious that I am
> doing something wrong the system should be stable!
> 
>> -Justin
>>
>>> Bryn
>>> _______________________________________________
>>> gmx-users mailing list    gmx-users at gromacs.org
>>> http://www.gromacs.org/mailman/listinfo/gmx-users
>>> Please search the archive at http://www.gromacs.org/search before posting!
>>> Please don't post (un)subscribe requests to the list. Use the
>>> www interface or send it to gmx-users-request at gromacs.org.
>>> Can't post? Read http://www.gromacs.org/mailing_lists/users.php
>>>
>> --
>> ========================================
>>
>> Justin A. Lemkul
>> Graduate Research Assistant
>> Department of Biochemistry
>> Virginia Tech
>> Blacksburg, VA
>> jalemkul[at]vt.edu | (540) 231-9080
>> http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>>
>> ========================================
> _______________________________________________
> gmx-users mailing list    gmx-users at gromacs.org
> http://www.gromacs.org/mailman/listinfo/gmx-users
> Please search the archive at http://www.gromacs.org/search before posting!
> Please don't post (un)subscribe requests to the list. Use the 
> www interface or send it to gmx-users-request at gromacs.org.
> Can't post? Read http://www.gromacs.org/mailing_lists/users.php
> 

-- 
========================================

Justin A. Lemkul
Graduate Research Assistant
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================



More information about the gromacs.org_gmx-users mailing list