[Dune] UG grid - limit on grid size?

[Eike Mueller]

Oliver Sander wrote:

> Hm, interesting.  I have never seen this error message before.
> 
> What do you mean by 128x128x32x6 elements?
I construct the cubed sphere by arranging 6 cubes, each subdivided into 
128x128x32 elements, around a (hollow) cube. I then bend and 'glue' the 
24 faces together (I needed to build myself a 3d foam model to figure 
out how to do that...).
> 
> How much ram does your machine have?

3.9GB

> Are you using the StructuredGridFactory?
No, just GridFactory.

Thanks,

Eike

Can you please file a bug
> with a small test program so this doesn't get lost?
> 
> Thanks,
> Oliver
> 
> Am 05.10.2011 15:07, schrieb Eike Mueller:
>> Hi Oliver,
>>
>> this works, thanks a lot! After recompiling UG I can go up to
>> 64x64x16x6, but if I try 128x128x32x6 (~ 2^22, but again, it's a serial
>> run) I now get this:
>>
>> ERROR in InsertElement: ==> NdElPtrArray_GetMemAndCheckIDs( ) ERROR: No
>> memory for MGNDELEMBLK(theMG,j)
>> ERROR in InsertElement: ERROR by calling NdElPtrArray_GetMemAndCheckIDs()
>> terminate called after throwing an instance of 'Dune::GridError'
>>
>> I tried increasing the heap size in the uggrid construction
>>
>> uggrid = new Dune::UGGrid<3>(10000);
>>
>> but I still get the same error message.
>>
>> Cheers,
>>
>> Eike
>>
>> Oliver Sander wrote:
>>> Hi Eike!
>>> This is a known problem. Please see the FAQ entry 4.2 on the dune
>>> homepage
>>> for an explanation and a workaround.
>>> Cheers,
>>> Oliver
>>>
>>> Am 05.10.2011 14:23, schrieb Eike Mueller:
>>>> Dear Dune-list,
>>>>
>>>> I've used the UG grid factory to construct a UG grid on spherical shell
>>>> like this [1], basically following the instructions in [2]. It all 
>>>> works
>>>> fine, but fails (or rather hangs) once my grid reaches a certain 
>>>> size (I
>>>> found that if the number of elements is 25x25x25x6 = 93750 it's ok, but
>>>> for 26x26x26x6 = 105456 it fails). The number of nodes is about the 
>>>> same
>>>> as the number of elements. I do not get a runtime error message, but it
>>>> just hangs in
>>>>
>>>> uggrid = new Dune::UGGrid<3>;
>>>> uggrid = factory.createGrid();
>>>>
>>>> Now, I might be getting the memory allocation wrong (I've tried passing
>>>> a larger heapsize to to Dune::UGGrid<3> constructor), but I also saw
>>>> this discussion here [3] saying that there are limits on the size of 
>>>> the
>>>> UG grid that can be constructed (I do not compile with -DNDEBUG and 
>>>> this
>>>> is a serial run and from how I understand it the limit should be 2^32
>>>> elements in serial runs?).
>>>>
>>>> Basically, I've got a class called Cubedsphere, which has the private
>>>> data field
>>>>
>>>> Dune::GridFactory<Dune::UGGrid<3>> factory;
>>>> Dune::UGGrid<3>* uggrid;
>>>>
>>>> In the constructor I generate my grid vertices (I know the exact
>>>> expressions for the positions, so don't need to read them from file) by
>>>> first calling
>>>>
>>>> factory.insertVertex(vertex);
>>>>
>>>> for all vertices and storing their ids and positions (both as unsigned
>>>> ints) in a lookup table and then generating the elements from the
>>>> entries in the lookup table with
>>>>
>>>> factory.insertElement(cube,vertices);
>>>>
>>>> When all this is done I call
>>>>
>>>> uggrid = new Dune::UGGrid<3>;
>>>> uggrid = factory.createGrid();
>>>>
>>>> in the constructor and the class also has a method
>>>>
>>>> Dune::UGGrid<3>* getUGGrid() { return uggrid; };
>>>>
>>>> for returning a reference to the uggrid pointer.
>>>>
>>>>
>>>>
>>>> Thank you very much for any help,
>>>>
>>>> Eike
>>>>
>>>>
>>>>
>>>> [1] http://people.bath.ac.uk/em459/dune.html
>>>> [2]
>>>> http://www.dune-project.org/doc/doxygen/html/classDune_1_1GridFactory_3_01UGGrid_3_01dimworld_01_4_01_4.html 
>>>>
>>>>
>>>>
>>>> [3]
>>>> http://www.dune-project.org/flyspray/index.php?do=details&task_id=250#comment2700 
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Dune mailing list
>>>> Dune at dune-project.org
>>>> http://lists.dune-project.org/mailman/listinfo/dune
>>>
>>
>