[Gmsh] Max number of fields

[Christophe Geuzaine]

In such extreme cases I would precompute the desired mesh size constraints on a background mesh.

Christophe

> On 26 Oct 2018, at 18:01, Max Orok <morok at mevex.com> wrote:
> 
> Hello Alessandro, 
> 
> I tried to add fields to an empty model using the attached program.
> I think your main problem would be with the time needed to insert in a map. 
> 
> Here are some rough timings from adding the "Box" size field. 
> 
> 1    min   -      50,000
> 4    min   -      90,000
> 5    min   -    100,000
> 6.5 min   -    110,000
> 12 min    -    150,000
> 
> For really large numbers (millions, etc.), you might need preallocation instead of adding one-by-one. 
> I don't think this is possible with the current SDK.
> The SDK C++ header's add function "only" has an int return value, so around 4 billion is nominally the front-end limit. 
> 
> If the header was ever modified, I think the background meshes are tracked with a pointer map (from BackgroundMeshManager.h):  
> 
> static std::map<GEntity *, BGMBase *> data;
> 
> Using the max_size map method I got around 3.8e17. 
> The real number is probably much lower than that because of allocation problems etc.
> 
> Sincerely, 
> Max
> 
> On Fri, Oct 26, 2018 at 6:01 AM, Alessandro Vicini <alessandro.vicini at sitael.com> wrote:
>  
> 
> Hello Gmsh users, is there some limitation whatsoever to the number of fields that can be defined for mesh size control? I think I might need a “huge” number of fields for some automatic adaptive grid refinement…
> 
>  
> 
> A.
> 
>  
> 
>  
> 
> 
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> 
> 
> -- 
> Max Orok
> Contractor
> www.mevex.com
> 
> 
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— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine

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