[Gmsh] Characteristic Length

[Christophe Geuzaine]

Jehanzeb Hameed wrote:
>  >With a char length of 0.5, you should get (about) 4 division per side 
> of your square (4*0.5=2, which is the length of one side of the square).
> 
> Actually, I get 3 divisions per side (with length of each side being 
> .666). This is whats confusing me about characteristic length. How is 
> the "about" factor decided? 

It's up to numerical errors: computing the divisions on the lines
involves numerical integration. Try e.g. replacing lc=0.5 by lc=0.499.



> And how will the radius of the circumscribed 
> circles be determined ?
> 
> Thanks,
> -Jehanzeb
> 
> 
> On Fri, Mar 21, 2008 at 12:18 PM, Christophe Geuzaine 
> <cgeuzaine at ulg.ac.be <mailto:cgeuzaine at ulg.ac.be>> wrote:
> 
>     Jehanzeb Hameed wrote:
>      > Hi,
>      >
>      > I cant understand how "Characteristic Length" works in gmsh. I
>     specify 4
>      > points (which are corner of a square, bottom left = (-1,-1) , top
>     right
>      > = (1,1)  ). The points have characteristic length 0.5  . I mesh this
>      > domain. I cant figure out what the relationship between radius of the
>      > circumscribed circle and characteristic length is. The documentation
>      > says this:
>      >
>      > "The size of the mesh elements will then be computed by linearly
>      > interpolating these characteristic lengths on the initial mesh".
>      >
>      > I cant understand between what values is the size of the mesh
>     elements
>      > being interpolated. How can I find this out?
> 
> 
>     With a char length of 0.5, you should get (about) 4 division per side of
>     your square (4*0.5=2, which is the length of one side of the square).
> 
> 
> 
> 
>      >
>      > Thanks,
>      > -Jehanzeb
>      >
>      >
>      >
>      >
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> 
>     --
>     Prof. Christophe Geuzaine
>     University of Liege, Electrical Engineering and Computer Science
>     http://www.montefiore.ulg.ac.be/~geuzaine
>     <http://www.montefiore.ulg.ac.be/%7Egeuzaine>
> 
> 
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-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine