[gmx-users] Re: wierd behavior of mdrun

Justin A. Lemkul jalemkul at vt.edu
Sat Sep 5 01:29:20 CEST 2009 

Have you tried my suggestion from the last message of setting frequent output? 
Could your system just be collapsing at the outset of the simulation?  Setting 
nstxout = 1 would catch something like this.

There is nothing special about treating a protein in parallel vs. a system of 
water.  Since a system of water runs just fine, it seems even more likely to me 
that your system is simply crashing immediately, rather than a problem with 
Gromacs or the MPI implementation.

-Justin

Paymon Pirzadeh wrote:
> Regarding the problems I have on running protein system in parallel
> (runs without output), When I run pure water system, everything is fine,
> I have tested pure water systems 8 times larger than my protein system.
> while the former runs fine, the latter has problems. I have also tested
> pure water systems with approximately same number of sites in .gro file
> as in my protein .gro file, and with the same input file in terms of
> spitting outputs; they are fine.I would like to know what happens to
> GROMACS when a protein is added to the system. The cluster admin has not
> get back to me, but I still want to check there is no problem with my
> setup! (although my system runs fine in serial mode).
> Regards,
> 
> Payman
> 
> 
> 
> On Fri, 2009-08-28 at 16:41 -0400, Justin A. Lemkul wrote:
>> Payman Pirzadeh wrote:
>>> There is sth strange about this problem which I suspect it might be due to
>>> the mdp file and input. I can run the energy minimization without any
>>> problems (I submit the job and it apparently works using the same submission
>>> script)! But as soon as I prepare the tpr file for MD run, then I run into
>>> this run-without-output trouble.
>>> Again I paste my mdp file below (I want to run an NVT run):
>>>
>> There isn't anything in the .mdp file that suggests you wouldn't get any output. 
>>   The output of mdrun is buffered, so depending on your settings, you may have 
>> more frequent output during energy minimization.  There may be some problem with 
>> the MPI implementation in buffering and communicating data properly.  That's a 
>> bit of a guess, but it could be happening.
>>
>> Definitely check with the cluster admin to see if there are any error messages 
>> reported for the jobs you submitted.
>>
>> Another test you could do to force a huge amount of data would be to set all of 
>> your outputs (nstxout, nstxtcout, etc) = 1 and run a much shorter simulation (to 
>> prevent massive data output!); this would force more continuous data through the 
>> buffer.
>>
>> -Justin
>>
>>> cpp              = cpp
>>> include          = -I../top
>>> define           = -DPOSRES
>>>
>>> ; Run control
>>>
>>> integrator       = md
>>> dt               = 0.001           ;1 fs
>>> nsteps           = 3000000         ;3 ns
>>> comm_mode        = linear
>>> nstcomm          = 1
>>>
>>> ;Output control
>>>
>>> nstxout          = 5000
>>> nstlog           = 5000
>>> nstenergy        = 5000
>>> nstxtcout        = 1500
>>> nstvout          = 5000
>>> nstfout          = 5000
>>> xtc_grps         =
>>> energygrps       =
>>>
>>> ; Neighbour Searching
>>>
>>> nstlist          = 10
>>> ns_type          = grid
>>> rlist            = 0.9
>>> pbc              = xyz
>>>
>>> ; Electrostatistics
>>>
>>> coulombtype      = PME
>>> rcoulomb         = 0.9
>>> ;epsilon_r        = 1
>>>
>>> ; Vdw
>>>
>>> vdwtype          = cut-off
>>> rvdw             = 1.2
>>> DispCorr         = EnerPres
>>>
>>> ;Ewald
>>>
>>> fourierspacing  = 0.12
>>> pme_order       = 4
>>> ewald_rtol      = 1e-6
>>> optimize_fft    = yes
>>>
>>> ; Temperature coupling
>>>
>>> tcoupl           = v-rescale
>>> ld_seed          = -1
>>> tc-grps          = System
>>> tau_t            = 0.1
>>> ref_t            = 275
>>>
>>> ; Pressure Coupling
>>>
>>> Pcoupl           = no
>>> ;Pcoupltype       = isotropic
>>> ;tau_p            = 1.0
>>> ;compressibility  = 5.5e-5
>>> ;ref_p            = 1.0
>>> gen_vel          = yes
>>> gen_temp         = 275
>>> gen_seed         = 173529
>>> constraint-algorithm     = Lincs
>>> constraints      = all-bonds
>>> lincs-order              = 4
>>>
>>> Regards,
>>>
>>> Payman
>>>  
>>>
>>> -----Original Message-----
>>> From: gmx-users-bounces at gromacs.org [mailto:gmx-users-bounces at gromacs.org]
>>> On Behalf Of Mark Abraham
>>> Sent: August 27, 2009 3:32 PM
>>> To: Discussion list for GROMACS users
>>> Subject: Re: [gmx-users] Re: wierd behavior of mdrun
>>>
>>> Vitaly V. Chaban wrote:
>>>> Then I believe you have problems with MPI.
>>>>
>>>> Before I experienced something alike on our old system - serial
>>>> version worked OK but parallel one failed. The same issue was with
>>>> CPMD by the way. Another programs worked fine. I didn't correct that
>>>> problem...
>>>>
>>>> On Thu, Aug 27, 2009 at 7:14 PM, Paymon Pirzadeh<ppirzade at ucalgary.ca>
>>> wrote:
>>>>> Yes,
>>>>> it works when it is run on one processor interactively!
>>> That's fine, but it doesn't mean the problem is with the parallelism, as 
>>> Vitaly suggests. If your cluster filesystem isn't configured properly, 
>>> you will observe these symptoms. Since the submission script was the 
>>> same, MPI worked previously, so isn't likely to be the problem...
>>>
>>> Mark
>>>
>>>>> On Thu, 2009-08-27 at 09:23 +0300, Vitaly V. Chaban wrote:
>>>>>>> I made a .tpr file for my md run without any problems (using the bottom
>>>>>>> mdp file). My job submission script is also the same thing I used for
>>>>>>> other jobs which had no problems. But now when I submit this .tpr file,
>>>>>>> only an empty log file is generated! The qstat of the cluster shows
>>> that
>>>>>>> the job is running, also the processors are 100% engaged while I have
>>> no
>>>>>>> outputs!
>>>>>> A standard guess: what about trying to run the single-processor job on
>>>>>> the same cluster? Does it run OK?
>>>>>>
>>>>>>
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> 
> 

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

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
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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