Re: domain decomposition problem

From: Yves Revaz <yves.revaz_at_obspm.fr>
Date: Tue, 17 Apr 2007 09:19:48 +0200

Javiera,

This problem occurs typically when the distance between two or more
particles is to small compared to the system size. In this case, the
tree must be
very deep and the allocated memory is not large enough to contain it.

If possible, you should increase the allocated memory to the tree
construction,
by increasing the parameter TreeAllocFactor.

However, in some cases, especially when you have a very dissipative
component, some
particles may form clumps and it will be difficult to avoid the problem.

Regards,

Yves




Javiera Guedes wrote:

>
> Hi all,
>
> I'm trying to use Gadget2 to evolve a galaxy with halo, gas, and star
> particles. I was running this on a single processor until I got an
> account at the Pleiades, a brand new supercomputer at UCSC. I get the
> following error:
>
> **********************************************************
> This is Gadget, version `2.0'.
>
> Running on 8 processors.
>
> Allocated 50 MByte communication buffer per processor.
>
> Communication buffer has room for 1008246 particles in gravity
> computation
> Communication buffer has room for 409600 particles in density computation
> Communication buffer has room for 327680 particles in hydro computation
> Communication buffer has room for 304818 particles in domain
> decomposition
>
>
> Hubble (internal units) = 4.13479
> G (internal units) = 0.999652
> UnitMass_in_g = 6.30712e+48
> UnitTime_in_s = 1.27586e+18
> UnitVelocity_in_cm_per_s = 6.91e+07
> UnitDensity_in_cgs = 9.20417e-30
> UnitEnergy_in_cgs = 3.01153e+64
>
> Task=0 FFT-Slabs=32
> Task=1 FFT-Slabs=32
> Task=2 FFT-Slabs=32
> Task=3 FFT-Slabs=32
> Task=4 FFT-Slabs=32
> Task=5 FFT-Slabs=32
> Task=6 FFT-Slabs=32
> Task=7 FFT-Slabs=32
>
> Allocated 8.0625 MByte for FFT kernel(s).
>
>
> Allocated 20.0963 MByte for particle storage. 80
>
> Allocated 4.09163 MByte for storage of SPH data. 84
>
>
> reading file `/home/javiera/ICs/MW1.bh.000.gadget' on task=0 (contains
> 1404834 particles.)
> distributing this file to tasks 0-7
> Type 0 (gas): 272409 (tot= 0000272409) masstab=0
> Type 1 (halo): 951539 (tot= 0000951539) masstab=0
> Type 2 (disk): 0 (tot= 0000000000) masstab=0
> Type 3 (bulge): 0 (tot= 0000000000) masstab=0
> Type 4 (stars): 180886 (tot= 0000180886) masstab=0
> Type 5 (bndry): 0 (tot= 0000000000) masstab=0
>
> reading done.
> Total number of particles : 0001404834
>
> allocated 0.0762939 Mbyte for ngb search.
>
> Allocated 15.6342 MByte for BH-tree. 64
>
> domain decomposition...
> NTopleaves= 834
>
> *No domain decomposition that stays within memory bounds is possible.*
>
> **************************************************************
>
> The relevant options on my parameter files are:
>
> % Memory allocation
>
> PartAllocFactor 1.5
> TreeAllocFactor 0.8
> BufferSize 50 % in MByte
>
>
> And my makefile options are:
> OPT += -DUNEQUALSOFTENINGS
> OPT += -DPEANOHILBERT
> OPT += -DWALLCLOCK OPT += -DSYNCHRONIZATION
>
> Any suggestions would be much appreciated.
>
> Thanks,
> -- Javiera
>
> -----------------------------------
> Javiera Guedes UCSC Astronomy Department
> javiera_at_astro.ucsc.edu
> ph: (831) 459-5722 fax: (831) 459-5265
> -----------------------------------
>
>
>
>
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-- 
                                                (o o)
--------------------------------------------oOO--(_)--OOo-------
  Yves Revaz
  Lerma Batiment A           Tel : ++ 33 (0) 1 40 51 20 79
  Observatoire de Paris      Fax : ++ 33 (0) 1 40 51 20 02 
  77 av Denfert-Rochereau    e-mail : yves.revaz_at_obspm.fr
  F-75014 Paris              Web : http://obswww.unige.ch/~revaz/
  FRANCE             
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Received on 2007-04-17 09:19:48

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