Re: Calculations on data on triangular mesh.

[Juan Pablo Carbajal]

On Thu, Oct 25, 2012 at 4:25 PM, Richard Crozier <address@hidden> wrote:
> Hi,
>
> I want to do some post-processing of data generated using a 2D finite
> element code. The code produces the nodal quantities of the solution on a
> delauney triangulation. The data I have in the solution are the vertex
> locations, a map of these vertices for the triangles and values of the
> solution at the vertices.
>
> What I would like to know is, is there a library of functions for
> efficiently working with this kind of data? The kind of operations I am
> interested in are interpolation at arbitrary points, integration over
> regions of the triangulation, getting triangle areas, centroids etc etc. I
> would like to avoid writing all this code from scratch.
>
> I have looked around for this on Octave Forge and so on, but haven't come
> across anything appropriate yet.
>
> The code in question by the way is freely available and hosted here:
>
> https://sourced.ecdf.ed.ac.uk/projects/see/xfemm
>
> It is a mex interface I have created to the core C++ magnetics solver from
> this program:
>
> http://www.femm.info/wiki/HomePage
>
>
>
>
> --
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Hi Richard,

Thank you for your link. Are you in contact with the developer of
FEMM. I also use it but since it is not licensed under a
GPL-compatible license we cannot add an interface in Octave Forge.

You may find the packages msh, fpl and geometry relatively useful.
There is many functionality missing and it would be great if you
develop anything missing that you share it we us.

To interpolate in a triangular mesh you could build the trick with
griddata, but the best is to write your own bilinear interpolation (if
that is what you want) on the triangles. I have code but is not
documented. I can share if you want, but I do not promise good quality
:D. Indeed... I may wrote a function to interpolate on a triangular
mesh after the 29th...

I am forwarding Carlo who is the one actively developing most of the FEM tools.