Hello Ricardo,

I tried to decrease the integration time but I got the same error.
The system is running fine in my local core.

I have two questions:

1) What do you mean by "I balance the domain decomposition for the larger number of core"?
2) Are you running simulations at Bluegene P at Rice University?

Thank you,
Cíntia


On 30/01/2013 20:48, Ricardo Soares wrote:
Hello,

before submitting to Bluegene, I always test the system in my local 8 core
cpu, and if it works, it will also work in Bluegene, as long as I balance the
domain decomposition for the larger number of cores. If your system insists in
exploding, even after energy minimization, you could try to decrease the
integration timestep (dt) to something lower than 2 fs, maybe to 1fs or, in
some cases even 0.5 fs. Did you tried that?

Cheers,

Ricardo.



On Wed, 30 Jan 2013 15:44:53 -0200, Cintia C. Vequi-Suplicy wrote
Mark,

Thank you for your answer.

I did an energy minimization with the file em.mdp (below) and then I
did a  40 ns simulation with the same md.mdp I send before. These
two steps were done in my local cluster. After that I took the
configuration for the simulation in the bluegene and I got these
error. I notice that the step that the error occurs depends on the
number of nodes I use. I am also including the end of the min.out file.

I also tried others integrators for the energy minimization but I
always get the same error.

Thank you again,
Cíntia

-------------------------------------------------------
em.mdp

integrator               = steep
tinit                    = 0.0
dt                       = 0.002
nsteps                   = 5000000
nstcomm                  = 1
comm-grps                = Other SOL

nstxout                  = 100
nstvout                  = 100
nstfout                  = 0
nstlog                   = 100
nstenergy                = 100
nstxtcout                = 100
xtc_precision            = 100
xtc-grps                 =
energygrps               = Other SOL

nstlist                  = 5
ns_type                  = grid
pbc                      = xyz
rlist                    = 1.4

coulombtype              = reaction-field
rcoulomb                 = 1.4
epsilon_rf               = 66

vdw_type                 = cut-off
rvdw                     = 1.4
DispCorr                 = No

constraints              = none
-------------------------------------------------------
min.out
...
Step= 5192, Dmax= 1.9e-11 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Step= 5193, Dmax= 9.5e-12 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Step= 5194, Dmax= 4.7e-12 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Step= 5195, Dmax= 2.4e-12 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Step= 5196, Dmax= 2.8e-12 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Step= 5197, Dmax= 1.4e-12 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Step= 5198, Dmax= 1.7e-12 nm, Epot= -1.79302e+06 Fmax= 6.65023e+02,
atom= 22015
Stepsize too small, or no change in energy.
Converged to machine precision,
but not to the requested precision Fmax < 10
You might need to increase your constraint accuracy, or turn
off constraints alltogether (set constraints = none in mdp file)

writing lowest energy coordinates.

Steepest Descents converged to machine precision in 5199 steps,
but did not reach the requested Fmax < 10.
Potential Energy  = -1.79302464181879e+06
Maximum force     =  6.65022934447791e+02 on atom 22015
Norm of force     =  4.90065871184878e+00

gcq#0: Thanx for Using GROMACS - Have a Nice Day
-------------------------------------------------------


     -------------------------------------------------------
     md.mdp file


     integrator               = md
     tinit                    = 0.0
     dt                       = 0.002
     nsteps                   = 5000000
     nstcomm                  = 5
     comm-grps                = Other SOL

     nstxout                  = 1000
     nstvout                  = 1000
     nstfout                  = 0
     nstlog                   = 1000
     nstenergy                = 1000
     nstxtcout                = 1000
     xtc_precision            = 1000
     xtc-grps                 =
     energygrps               = Other SOL

     nstlist                  = 5
     ns_type                  = grid
     pbc                      = xyz
     rlist                    = 1.4

     coulombtype              = reaction-field
     rcoulomb                 = 1.4
     epsilon_rf               = 66

     vdw_type                 = cut-off
     rvdw                     = 1.4
     DispCorr                 = No

     tcoupl                   = v-rescale
     tc-grps                  = Other SOL
     tau_t                    = 0.4 0.4
     ref_t                    = 296 296

     Pcoupl                   = berendsen
     Pcoupltype               = semiisotropic
     tau_p                    = 0.2 0.2
     compressibility          = 4.51e-5 4.51e-5
     ref_p                    = 1.0 1.0

     constraints              = hbonds
     constraint_algorithm     = lincs

--
gmx-users mailing list    gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
* Please search the archive at
http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
* Please don't post (un)subscribe requests to the list. Use the www
interface or send it to gmx-users-requ...@gromacs.org. * Can't post?
Read http://www.gromacs.org/Support/Mailing_Lists

--
gmx-users mailing list    gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
* Please search the archive at 
http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
* Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org.
* Can't post? Read http://www.gromacs.org/Support/Mailing_Lists

Reply via email to