[Nek5000-users] Seg. fault in running a backward facing step case.

[nek5000-users at lists.mcs.anl.gov]

I typically set lorder=4


On Fri, 9 Apr 2010, nek5000-users at lists.mcs.anl.gov wrote:

> For the moment you're ok if:
>
> TORDER=2, LORDER=3, LELT=NELT/NP + 1
> TORDER=2, LORDER=3, LELT= (3/2) * NELT/NP + 1
> TORDER=3, LORDER=3, LELT= (4/3) * NELT/NP + 1
>
> hth,
> Stefan
>
> On Apr 9, 2010, at 6:12 PM, nek5000-users at lists.mcs.anl.gov wrote:
>
>> Thanks for the help!!
>>
>> Harish
>>
>> On Fri, 9 Apr 2010 nek5000-users at lists.mcs.anl.gov wrote:
>>
>>> Yes that's true. I'll discuss with the other developers how this can be improved. Also we're working on a fix to avoid the SEGFAULT.
>>>
>>> Stefan
>>>
>>>
>>> On Apr 9, 2010, at 6:05 PM, nek5000-users at lists.mcs.anl.gov wrote:
>>>
>>>> Hi Stefan,
>>>>
>>>> Thanks for your reply. Compiling with with a larger lelt and OIFS on the code worked.
>>>>
>>>> So what I understand from your reply is that if OIFS is ON the code requires more memory
>>>> and it should be compiled with more lelt rather than the exact lelt=lelg/lp.
>>>>
>>>> Harish.
>>>>
>>>>
>>>> On Fri, 9 Apr 2010 nek5000-users at lists.mcs.anl.gov wrote:
>>>>
>>>>> Harish,
>>>>>
>>>>> when we try to exit the code with an error message the code crashes. You turned on OIFS (T IFCHAR) but you don't have enough memory available. I think you can just increase lelt to avoid this problem. Anyway the code should print out a reasonable err-msg and not a SEGFAULT!
>>>>>
>>>>>
>>>>> Stefan
>>>>>
>>>>>
>>>>>
>>>>> On Apr 9, 2010, at 4:33 PM, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> I am trying to simulate flow in a 3D backward facing step (BFS) geometry.
>>>>>>
>>>>>> I have attached the *.box file and n2to3.in file that I use to create the
>>>>>> 3D geometry. For reference logfile, *.rea and *.usr files are attached.
>>>>>> The code is compiled with GNU compiler and OpenMPI. The code is compiled
>>>>>> for 16 processors and compiler.out file is attached as well.
>>>>>>
>>>>>> When I run the code, I get a seg. fault. After running the "gdb" tool on
>>>>>> the core.* file, I get the following output. I have attached the gdb
>>>>>> output file too.
>>>>>> ===========================================================================
>>>>>> Core was generated by `./nek5000'.
>>>>>> Program terminated with signal 11, Segmentation fault.
>>>>>> [New process 7652]
>>>>>> #0  0x0000000000488768 in chcopy_ ()
>>>>>> ===========================================================================
>>>>>>
>>>>>> 3D BFS geometry has a wall at the bottom and symmetry b.c. at the top. But
>>>>>> if I change the top b.c. with wall the simulation works. For reference I
>>>>>> have attached the job output file.
>>>>>>
>>>>>> Initially, I thought the problem was with memory limitations on my cluster
>>>>>> for a bigger geometry. So I tried a smaller geometry, but I still kept
>>>>>> getting seg. faults.
>>>>>>
>>>>>> Help with solving this problem will be greatly appreciated. And sorry for
>>>>>> attaching so many files.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Harish.<bfs.box><n2to3.in><logfile><bfs3d.rea><bfs3d.usr><Backstp.2323.o><gdb.output><compiler.out>_______________________________________________
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>>>>>> Nek5000-users at lists.mcs.anl.gov
>>>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>>>>
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