On Fri, Oct 26, 2012 at 5:22 AM, Nicholas Jankowski <address@hidden> wrote:
> On Thu, Oct 25, 2012 at 3:22 PM, Juan Pablo Carbajal <address@hidden>
> wrote:
>>
>> On Thu, Oct 25, 2012 at 9:19 PM, Juan Pablo Carbajal
>> <address@hidden> wrote:
>> > On Thu, Oct 25, 2012 at 9:03 PM, Richard <address@hidden> wrote:
>> >> On 25/10/2012 18:57, Juan Pablo Carbajal wrote:
>> >>>
>> >>> 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 co!
de
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 wr!
iting
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
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> --
>> >>>> View this message in context:
>> >>>>
>> >>>> http://octave.1599824.n4.nabble.com/Calculations-on-data-on-triangular-mesh-tp4645732.html
>> >>>> Sent from the Octave - General mailing list archive at Nabble.com.
>> >>>>
>> >>>> Help-octave mailing list
>> >>>> address@hidden
>> >>>> https://mailman.cae.wisc.edu/listinfo/help-octave
>> >>>
>> >>> 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 triangu!
lar
>> >>> mesh after the 29th...
>> >>>
>> >>> I am forwarding Carlo who is the one actively developing most of the
>> >>> FEM
>> >>> tools.
>> >>>
>> >>
>> >> Juan,
>> >>
>> >> I am in contact occasionally with the FEMM author, but he was not
>> >> interested
>> >> in my proposal which was to let me use my modified version of the
>> >> magnetics
>> >> solver code under an LGPL licence. I don't know if the FEMM author
>> >> would be
>> >> any more interested in the full GPL or another licence. In any case it
>> >> uses
>> >> Triangle (made by Jonathan Shrewchek) which is provided under similar
>> >> terms
>> >> to FEMM.
>!
>
>>
>> >> If you use FEMM, you might find my code useful, I have made a function
>> >> (writefemmfile.m) which can output a file in FEMM's input format given
>> >> a
>> >> problem definition stored as a normal Octave/Matlab structure. The FEMM
>> >> solver C++ code can also be compiled as a standalone executable as well
>> >> as a
>> >> mexfunction. The mexfunction works with Octave, too. My 'interface'
>> >> mexfunction though really just calls the FEMM code with a string
>> >> containing
>> >> the name of .fem file. I have replaced all the Windows-only MFC code
>> >> with
>> >> standard C++ so it can also be compiled on linux, and doesn't require
>> >> Wine.
>> >> I have also created a lot of helper functions in m-code for creating
>> >> the
>> >> problem structure (e.g. addnode_mfemm.m, addsegment_mfemm.m and
>> >> similar).
>> >> These are analagous to the existing OctaveFEMM interface code.
>> >>
>> >> Note this is only the magnetics solver though.
>> >>
>> >> I want to implement all the post-processing capabilities of FEMM, but
>> >> in
>> >> Matlab and Octave compatible code. All mcode I have written for
>> >> pre-processing (problem definition) and post-processing is released
>> >> under
>> >> the Apache V2.0 licence. The modified FEMM sources are provided under
>> >> an
>> >> Aladdin Free Public Licence.
>> >>
>> >> At some point in the long term future I can consider replacing the
>> >> actual
>> >> solver code as well with something with a less restrictive licence. The
>> >> alternative is to write a magnetics solver for FAESOR which is a 3D GPL
>> >> finite element package for Matlab (haven't tested this extensively in
>> >> Octave, but I'm pretty sure it works, apart from some visualisation
>> >> code.).
>> >> You can find FAESOR here:
>> >>
>> >> http://hogwarts.ucsd.edu/~pkrysl/faesor/faesor_publish.html
>> >>
>> >> In case you are interested. If you would like to help make the
>> >> post-processing code for my FEMM interface, you, or anyone else are
>> >> more
>> >> than welcome!
>> >>
>> >> Richard
>> >>
>>
>>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> --
>> >> The University of Edinburgh is a charitable body, registered in
>> >> Scotland, with registration number SC005336.
>> >>
>> >
>> > Hi Richard,
>> >
>> > Yeah, I also contact Meeks once but couldn't get it under a free
>> > compatible license. I think he is using some other code that he can't
>> > release. Anyways...
>> >
>> > I will definitely take a look at your code. Though post-processing is
>> > not the exiting task for me (I mean there is so much already freed out
>> > there, paraview for example, though I am not sure if the license is
>> > truly free, but looks like BSD to me), please keep me
updated. I am
>> > already with too many projects, but who knows maybe I drop some of
>> > them.
>> >
>> > Thanks!
>>
>> Also I took a look quickly at FAESOR. It should work in Octave, it
>> would be nice to get it into Octave Forge ...
>>
>
>
> maybe not right out of the box. downloaded it and ran it, immediate error:
>
> -----------------------
> syntax error
>
>>>> addpath([homePath sep '..' sep
>>>> 'CXSparse/MATLAB/CSparse'],....
>
> ^
> ------------------------
> probably not a big deal to pull all the Matlab specific code, but it's in
> there.
mmm... the problem is under what license is that coded released. If it
isn't GPL-compatible, or there isn't Octave equivalents, then we will
not have it. :(!
Thanks Nicholas