[gmx-users] Domain decomposition configuration

Justin A. Lemkul jalemkul at vt.edu
Wed Feb 9 22:10:02 CET 2011



Denny Frost wrote:
> Is tpbconv with the "pbc" option the best way to make the molecules 
> whole again?
> 

The only way, as far as I'm aware (aside from editconf's crude approach).  Do 
this before you concatenate your systems.

-Justin

> On Wed, Feb 9, 2011 at 2:06 PM, Justin A. Lemkul <jalemkul at vt.edu 
> <mailto:jalemkul at vt.edu>> wrote:
> 
> 
> 
>     Denny Frost wrote:
> 
>         This run is actually a combination of two 5x5x5 nm boxes, one if
>         which was previously run in DD, and the other is water.  Since
>         the length of that bond is almost 5 nm, is it possible that the
>         pbc's are not being recognized?  There is no way I have a bond
>         that long from my previous run.
> 
> 
>     I'll venture a guess that there were broken molecules in the system
>     you concatenated?  That would gel with a bond that stretches across
>     a 5-nm box.  You have to deal with whole molecules in the input
>     configuration.
> 
>     -Justin
> 
>         On Wed, Feb 9, 2011 at 1:56 PM, Justin A. Lemkul
>         <jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>         <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>> wrote:
> 
> 
> 
>            Denny Frost wrote:
> 
>                I'm using version 4.5.3
> 
>                Here's the output from the log file from DD initiation to
>         the error:
> 
>                Initializing Domain Decomposition on 8 nodes
>                Dynamic load balancing: auto
>                Will sort the charge groups at every domain (re)decomposition
>                Initial maximum inter charge-group distances:
>                   two-body bonded interactions: 4.893 nm, Bond, atoms
>         8994 8996
>                 multi-body bonded interactions: 4.893 nm, Angle, atoms
>         8994 8997
>                Minimum cell size due to bonded interactions: 5.382 nm
> 
> 
>            Bonded interactions should normally not occur over such a length.
>             The information printed here points to the culprits.  What are
>            these atoms, and why are they bonded if they are so far away?
> 
>            -Justin
> 
>                Using 0 separate PME nodes
>                Scaling the initial minimum size with 1/0.8 (option -dds)
>         = 1.25
>                Optimizing the DD grid for 8 cells with a minimum initial
>         size
>                of 6.728 nm
>                The maximum allowed number of cells is: X 0 Y 0 Z 1
> 
>                -------------------------------------------------------
>                Program mdrun_mpi, VERSION 4.5.3
>                Source code file: domdec.c, line: 6428
> 
>                Fatal error:
>                There is no domain decomposition for 8 nodes that is
>         compatible
>                with the given box and a minimum cell size of 6.72787 nm
>                Change the number of nodes or mdrun option -rdd or -dds
>                Look in the log file for details on the domain decomposition
>                For more information and tips for troubleshooting, please
>         check
>                the GROMACS
>                website at http://www.gromacs.org/Documentation/Errors
> 
>                And here is my mdp file
> 
>                title               =  BMIM+PF6
>                cpp                 =  /lib/cpp
>                constraints         =  hbonds
>                integrator          =  md
>                dt                  =  0.002   ; ps !
>                nsteps              =  75000   ; total 150 ps
>                nstcomm             =  10
>                nstxout             =  50000
>                nstvout             =  50000
>                nstfout             =  0
>                nstlog              =  5000
>                nstenergy           =  5000
>                nstxtcout           =  25000
>                nstlist             =  10
>                ns_type             =  grid
>                pbc                 =  xyz
>                coulombtype         =  PME
>                vdwtype             =  Cut-off
>                rlist               =  1.2
>                rcoulomb            =  1.2
>                rvdw                =  1.2
>                fourierspacing      =  0.12
>                pme_order           =  4
>                ewald_rtol          =  1e-5
>                ; Berendsen temperature coupling is on in two groups
>                Tcoupl              =  berendsen
>                tc_grps             =  BMI      PF6     SOL tau_t        
>                      =  0.2  0.2  0.2
>                ref_t               =  300  300  300
>                nsttcouple          =  1
>                ; Energy monitoring
>                energygrps          =  BMI      PF6     SOL
>                ; Isotropic pressure coupling is now on
>                Pcoupl              =  berendsen
>                pcoupltype          =  isotropic
>                ;pc-grps             =  BMI      PFF
>                tau_p               =  2.0
>                ref_p               =  1.0
>                compressibility     =  4.5e-5
> 
>                ; Generate velocites is off at 300 K.
>                gen_vel             =  yes
>                gen_temp            =  300.0
>                gen_seed            =  100000
> 
> 
>                On Wed, Feb 9, 2011 at 1:39 PM, Justin A. Lemkul
>                <jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>         <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>
>                <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>         <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>>> wrote:
> 
> 
> 
>                   Denny Frost wrote:
> 
>                       I am trying to start a run using domain
>         decomposition on a
>                       5x5x10 nm box with about 26,000 atoms in it.  I've
>         tried
>                running
>                       8-16 pp nodes, but gromacs always throws an error
>         saying that
>                       there is no domain decomposition compatible with
>         this box
>                and a
>                       minimum cell size of 6.728 nm.  I've tried many values
>                for -dds
>                       and a few dd vectors, but with no luck.  Does
>         anyone know
>                to get
>                       domain decomposition working on a rectangular
>         system like
>                this?
> 
> 
>                   Not without significantly more information.  Please post:
> 
>                   1. Your Gromacs version
>                   2. Any DD-related information that is printed to
>         either the
>                log file
>                   or stdout
>                   3. Your .mdp file
> 
>                   -Justin
> 
>                   --     ========================================
> 
>                   Justin A. Lemkul
>                   Ph.D. Candidate
>                   ICTAS Doctoral Scholar
>                   MILES-IGERT Trainee
>                   Department of Biochemistry
>                   Virginia Tech
>                   Blacksburg, VA
>                   jalemkul[at]vt.edu <http://vt.edu> <http://vt.edu>
>         <http://vt.edu> | (540)
> 
>                231-9080
> 
>                   http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
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>            --     ========================================
> 
>            Justin A. Lemkul
>            Ph.D. Candidate
>            ICTAS Doctoral Scholar
>            MILES-IGERT Trainee
>            Department of Biochemistry
>            Virginia Tech
>            Blacksburg, VA
>            jalemkul[at]vt.edu <http://vt.edu> <http://vt.edu> | (540)
>         231-9080
>            http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
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> 
>     -- 
>     ========================================
> 
>     Justin A. Lemkul
>     Ph.D. Candidate
>     ICTAS Doctoral Scholar
>     MILES-IGERT Trainee
>     Department of Biochemistry
>     Virginia Tech
>     Blacksburg, VA
>     jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
>     http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
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-- 
========================================

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
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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