[gmx-users] Unexplained crashes with Gromacs-4.0

Justin A. Lemkul jalemkul at vt.edu
Tue Oct 14 13:44:07 CEST 2008



David van der Spoel wrote:
> Justin A. Lemkul wrote:
>>
>>
>> Berk Hess wrote:
>>> Hi,
>>>
>>> I don't really know what could be the problem here.
>>>
>>> 0..180 is (confusingly) not including the end, so 180 is out of range.
>>>
>>> The only thing I can think of (except for unknown bugs of coarse),
>>> is that I corrected the coupling time of the Parrinello-Rahman barostat
>>> when going from 4.0 RC4 to the official 4.0 release.
>>> I guess all your old simulations were with older Gromacs releases.
>>> So to get the same coupling as before, so would need to multiply 
>>> tau_t by 16.6.
>>> I don't know if this would help.
>>
>> I did see this same error under RC2, but noticed that you fixed this 
>> bug shortly after I saw it, and that's what I assumed it was.  But now 
>> I have seen it under the official 4.0 release.
>>
>>>
>>> You did not get pressure coupling warnings before the crash?
>>>
>>
>> There are no messages printed before this error pops up.  What's 
>> really confusing is that if I simply try the same .tpr file again, it 
>> runs without a problem.  I know that's not terribly scientific, but it 
>> seemed odd to me that my systems running for 40+ ns suddenly had a 
>> problem.
>>
>> Is there any diagnostic information I can provide?  This problem seems 
>> like it would be elusive, since even I can't fully reproduce it.
> 
> That sounds like hardware problems, unless you use dynamic load 
> balancing which depends on timings and hence may make runs irreproducible.
> 

That might be it then.  I use -dlb auto, and in the mdrun output to the logfile, 
it reports that it is turning on dynamic load balancing.  Is there any way to 
diagnose this, i.e. -dlb no?  Or is this a problem I'm stuck with based on my 
hardware?

-Justin

>>
>> -Justin
>>
>>> Berk
>>>
>>>
>>> ------------------------------------------------------------------------
>>>  > Date: Mon, 13 Oct 2008 16:55:20 -0400
>>>  > From: jalemkul at vt.edu
>>>  > To: gmx-users at gromacs.org
>>>  > Subject: [gmx-users] Unexplained crashes with Gromacs-4.0
>>>  >
>>>  >
>>>  > Hi,
>>>  >
>>>  > I've gotten the following error with two of my simulation systems. 
>>> Usually this
>>>  > weird "variable ci" error means the system is unstable, and I've 
>>> seen it before
>>>  > when I've done a poor job of equilibrating. But now I'm seeing it 
>>> a long time
>>>  > into my simulations (after 48 ns in one case, 60 ns in the other). 
>>> If I simply
>>>  > re-submit the job, it runs fine. The error shown is as follows:
>>>  >
>>>  > -------------------------------------------------------
>>>  > Program mdrun_4.0_mpi, VERSION 4.0
>>>  > Source code file: nsgrid.c, line: 357
>>>  >
>>>  > Range checking error:
>>>  > Explanation: During neighborsearching, we assign each particle to 
>>> a grid
>>>  > based on its coordinates. If your system contains collisions or 
>>> parameter
>>>  > errors that give particles very high velocities you might end up 
>>> with some
>>>  > coordinates being +-Infinity or NaN (not-a-number). Obviously, we 
>>> cannot
>>>  > put these on a grid, so this is usually where we detect those errors.
>>>  > Make sure your system is properly energy-minimized and that the 
>>> potential
>>>  > energy seems reasonable before trying again.
>>>  >
>>>  > Variable ci has value 180. It should have been within [ 0 .. 180 ]
>>>  >
>>>  > -------------------------------------------------------
>>>  >
>>>  > It seems to me that this "ci" variable is still within the range 
>>> of 0->180, if
>>>  > those values are inclusive.
>>>  >
>>>  > My .mdp file is as follows:
>>>  >
>>>  > title = NPT simulation for a membrane protein
>>>  > ; Run parameters
>>>  > integrator = md
>>>  > dt = 0.002
>>>  > nsteps = 5000000 ; 10000 ps (10 ns)
>>>  > tinit = 40000
>>>  > nstcomm = 1
>>>  > ; Output parameters
>>>  > nstxout = 50000 ; every 100 ps
>>>  > nstvout = 50000
>>>  > nstfout = 50000
>>>  > nstlog = 5000 ; every 10 ps
>>>  > nstenergy = 5000
>>>  > nstxtcout = 5000
>>>  > ; Bond parameters
>>>  > constraint_algorithm = lincs
>>>  > constraints = all-bonds
>>>  > continuation = yes
>>>  > ; Cut-off's and neighborsearching
>>>  > nstlist = 5
>>>  > ns_type = grid
>>>  > rlist = 1.2
>>>  > rcoulomb = 1.2
>>>  > rvdw = 1.2
>>>  > ; PME electrostatics parameters
>>>  > coulombtype = PME
>>>  > fourierspacing = 0.18
>>>  > ;fourier_nx = 0
>>>  > ;fourier_ny = 0
>>>  > ;fourier_nz = 0
>>>  > pme_order = 4
>>>  > ewald_rtol = 1e-5
>>>  > optimize_fft = yes
>>>  > ; Berendsen temperature coupling is on in three groups
>>>  > Tcoupl = Nose-Hoover
>>>  > tc_grps = Protein POPC SOL_NA+_CL-
>>>  > tau_t = 0.1 0.1 0.1
>>>  > ref_t = 310 310 310
>>>  > ; Pressure coupling is not on
>>>  > Pcoupl = Parrinello-Rahman
>>>  > pcoupltype = semiisotropic
>>>  > tau_p = 2.0
>>>  > compressibility = 4.5e-5 4.5e-5
>>>  > ref_p = 1.0 1.0
>>>  > ; Generate velocities is off
>>>  > gen_vel = no
>>>  > gen_temp = 310
>>>  > gen_seed = 7041776
>>>  > ; Periodic boundary conditions are on in all directions
>>>  > pbc = xyz
>>>  > ; Long-range dispersion correction
>>>  > DispCorr = EnerPres
>>>  >
>>>  > Any ideas what's going on?
>>>  >
>>>  > Thanks,
>>>  > Justin
>>>  >
>>>  > --
>>>  > ========================================
>>>  >
>>>  > 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
>>>  >
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>>
> 
> 

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

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

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



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