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August 28, 2009 1:01pm UTC

Numbering of the boundaries in *.m file

Hello all,

I am working on a parametric geometry model and I want to create my geometry/solution fully in script. I have to say that it is a rather complex geometry and till now I took the short and easy way by first creating my geometry in MatLab script with Comsol functions, exporting it to Comsol, doing the necessary subdomain and boundary settings there, exporting the model back to a "*.m" file (letting Comsol deal with the numbering for me) and proceeding with the solution.

Now, the geometry became more complex and the number of boundaries are not constant anymore and I need to understand how Comsol numbers the boundaries so that I can assign the correct boundary conditions without switching between Comsol and MatLab. When I look at bnd.ind=[] and equ.ind=[] there seems to be a logic behind the numbering but I couldn't be able to find any documentation explaining that systematic.

Thanks in advance,
Onur

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September 4, 2009 8:28am UTC in response to Onur Ilkorur

Re: Numbering of the boundaries in *.m file

Hello,

Comsol increment with a sort of triple loop (for x=1:end; for y=1:end; for z=1:end) to find the boundary number.

I have a matlab code which finds a face (or boundary) number (If you know the boundary position (x,y,z)).
the second matlab code finds vertex number.

I hope codes will help you,

Y.

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November 3, 2009 5:42pm UTC in response to Onur Ilkorur

Re: Numbering of the boundaries in *.m file

Hi,

This is an excellent function! Just should have provided an example of its use.

I would emphasis that the x,y,z co-ordinates are "rubberband" co-ordinates i.e.

face(fem.geom,[3.6e-6 3.8e-6],[4e-6 4.5e-6],[0 40e-6],1e-3,2)

Orginally I entered tol=1 which resulted in all the boundaries in the model being returned, this is because this is the tolerance and 1 = 1m which is larger than my model space.

I am still to work-out what the density is? I have it set to 2 and it is working well!

Good Work!!


Regards,
Tom

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April 13, 2010 3:59am UTC in response to Yannick fargier

Re: Numbering of the boundaries in *.m file

Hi Yannick,

This is amazing, but I cannot seem to get it to work in 2D :( can you advise me on how to get it done into2D? and it will give me the index of boundaries if I'm not wrong.

Thanks!

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