[Gmsh] Adjacent elements in finite volume formulation

[Jeremy Theler]

Hey Yuri
I asked the same question back in 2011:
http://onelab.info/pipermail/gmsh/2011/006878.html
All I got is a loose reference to Lohner's book:
http://onelab.info/pipermail/gmsh/2011/006881.html
Someone asked it again in 2012 with no response:
http://onelab.info/pipermail/gmsh/2012/007480.html
I went in again in 2013, again with no luck:
http://onelab.info/pipermail/gmsh/2013/008183.html
Something similar came back in 2014:
http://onelab.info/pipermail/gmsh/2014/008808.html
And again FVM:
http://onelab.info/pipermail/gmsh/2014/008908.htmlhttp://onelab.info/pi
permail/gmsh/2014/009237.html
In 2017 I already mentioned that this was unsolved:
http://onelab.info/pipermail/gmsh/2017/011248.html
One more time in 2018:
http://onelab.info/pipermail/gmsh/2018/012120.html

So... is this enough to have something in Gmsh's core?I proposed to add
an optional section like $ElementNeighbour$ or something like this,
listing the tag of the neighbours each elements has (including surface
elements for volumetric elements so boundary conditions in FEM can be
more efficiently written). I have somewhere a tool that reads a .msh
and adds such a section, if somebody is interested I can dig into my
archives and prepare a repository.
I bet the neighbour list can be generated in O(n) inside Gmsh, which
should beat any complex O(n log n) or naive O(n^2) implementention
outside Gmsh.
Regards--jeremy thelerwww.seamplex.com

On Fri, 2019-03-29 at 16:00 -0300, Yuri Barros wrote:
> Hi all,
> I am trying to optimize my finite volume formulation and one thing
> that is taking too much computational time is to find adjacent cells.
> Is there any way I can extract from GMSH the adjacent elements of a
> given element in the local face order? Or is there any algorithm that
> people use routinely for this task?
> 
> Thanks in advance!
> 
> _______________________________________________
> gmsh mailing list
> gmsh at onelab.info
> http://onelab.info/mailman/listinfo/gmsh
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://onelab.info/pipermail/gmsh/attachments/20190330/54232627/attachment.html>