[FLASH-USERS] Error in AMR Prolong Routine

[James Guillochon]

Anshu,

Thanks for the response. I am a bit skeptical that it is a memory  
issue, because the simulation runs without issue for 5000 steps and  
this crash recurs even after restarting from a checkpoint file only 36  
steps before the crash. Only a few blocks are refined and derefined  
during this period, whereas thousands are refined and derefined  
earlier in the simulation. So if this is a memory issue, it is one  
that arises very quickly.

Just to be clear, I do not have a modified Driver_sourceTerms.F90 file  
in this simulation, so I am never explicitly setting the density  
values myself.

-- 
James Guillochon
Department of Astronomy & Astrophysics
University of California, Santa Cruz
jfg at ucolick.org

On Apr 10, 2009, at 10:45 AM, Anshu Dubey wrote:

> James,
>
> There is no place where density gets set to 0 explicitly. Normally we
> encounter density going 0 only when the memory is getting trampled
> somewhere, and so there is some bug somewhere. If you are seeing this
> in the recv array, then you might be skirting too close to using up
> all the available memory on the system. One such situation we
> encounterd once  had to do with there being not enough memory for an
> allocate call, but instead of reporting error, the system returned the
> call and memory trampled.
>
> Anshu
>
> On Thu, Apr 9, 2009 at 12:04 AM, James Guillochon <jfg at ucolick.org>  
> wrote:
>> Hi guys,
>> I am running a simulation in FLASH 3.0 using multiple species, and  
>> after
>> about 5000 time steps, I run into the following error:
>> [amr_prolong_gen_unk1_fun] PE=      7, ivar= 13, value= 24.0
>>
>> Trying to convert non-zero mass-specific variable to per-volume  
>> form in
>> monotonic mesh interpolation, but dens is zero!
>> The ivar = 13 being referred to here is the first species in my  
>> species list
>> defined in Flash.h, which at the time of the abort is equal to smallx
>> everywhere. It appears from the code that the recv variable array  
>> must have
>> a zero value for density in at least one grid cell, but as far as  
>> I'm aware
>> the density variable should never drop below smallrho!
>> Tracking the origin of this issue could take a very long time, so I  
>> was
>> hoping someone here has encountered this issue before and knows of  
>> a remedy?
>> Is there anywhere in FLASH where the density is set explicitly to  
>> zero?
>> Thanks!
>> --
>> James Guillochon
>> Department of Astronomy & Astrophysics
>> University of California, Santa Cruz
>> jfg at ucolick.org
>>
>
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>