[Dune] Vector of IntersectionIterators

[Dragan Vidovic]

Hi Oliver

Thanks for the suggestion. I had that as a temporary solution, but as
the project grows it was getting too messy. This is why I started
storing the iterators. Do you know how can I at least destroy them
after use? I guess that creating an iterator creates something within
the ALUgrid space which stays there. Am I right?

Dragan


On Wed, Mar 17, 2010 at 8:51 AM, Oliver Sander <sander at mi.fu-berlin.de> wrote:
> Hi Dragan!
> Have you considered storing just the information that you need
> in several vectors?  For example, declare
>
> std::vector<FieldVector<double,dimworld> > normals;
> std::vector<double> areas;
> [...]
>
> Loop over the intersections of your current element once
> and fill the array.  Later you can access all information by index.
>
> Not the most elegant solution, but it should work.
>
> --
> Oliver
>
> Dragan Vidovic schrieb:
>>
>> Hi all
>>
>> I'm developing some very experimental finite volume methods and I
>> really need to store some kind of references to some faces, like
>> boundary faces or those where some physical parameters are
>> discontinuous, and use references these later to get areas, normals,
>> or to access neighbouring cells, without looping trough all cells
>> every time. Since mappers can only map from an IntersectionIterator to
>> an integer index and not the other way around, the only solution that
>> I found after allot of experimenting was to use a std::vector of
>> IntersectionIterators. Since an empty constructor for
>> IntersectionIterator is not allowed, I initialize it as
>>
>> std::vector<IntersectionIterator> ismap (nfaces,
>> gridView.ibegin(*gridView.template begin<0>()));
>>
>> and change it's elements later. There are two problems here:
>>
>> 1) This takes a hell of a space. I divided the increase in memory that
>> the process takes by the number of faces, and I found out that each
>> IntersectionIterator takes about 1k!
>>
>> 2) When this vector goes out of scope, this space is not recycled.
>>
>> I'm using the newest ALUgrid, and Dune not older than two weeks.
>>
>> Does anyone have some idea how to overcome these problems?
>>
>> Best regards,
>>
>> Dragan
>>
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>>
>
>
> --
> ************************************************************************
> * Oliver Sander                ** email: sander at mi.fu-berlin.de        *
> * Freie Universität Berlin     ** phone: + 49 (30) 838 75348           *
> * Institut für Mathematik      ** URL  : page.mi.fu-berlin.de/~sander  *
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>