[Gmsh] Different interpolation schemes

[Marios Papadopoulos]

Hello Martin,

I've checked the option you mentioned and nothing happened when I select
"vertex" and not "barycenter" for the Glyph Location. You can check it out
in a simple example with one quad element. Attached you will find scalar
field plotted in gmsh and the same contour plot taken from wikipedia lemma
(bilinear interpolation). (see
http://en.wikipedia.org/wiki/Bilinear_interpolation)

The question is, how I can use gmsh's $InterpolationScheme feature to get
the same contour plot inside the quad element?

Regards!


On Mon, Nov 4, 2013 at 2:14 PM, Martin Vymazal <martin.vymazal at vki.ac.be>wrote:

> Hello Marios,
>
>  could you check that gmsh plots the values in vertices and not in
> barycenters?
> You can verify this by clicking on Tools->Options, then select your
> postprocessing view, go to tab 'Aspect' and look at 'Glyph location'.
>
> Best regards,
>
>   Martin Vymazal
>
> On Sunday 03 November 2013 19:03:56 Marios Papadopoulos wrote:
> > Dear gmshers,
> >
> > attached you will find two contour plots from a scalar field. The first
> one
> > (contour1.png) was made with gmsh using $NodeData feature, without using
> > any extra $InterpolationScheme rule info. The second one (contour2.png)
> was
> > made using another post-processing software with the same nodal values.
> > This second image is the right represantion of the contour for the scalar
> > field.
> >
> > As you notice, gmsh interpolate the nodal values with a "wrong" way.
> > Ignoring the color mapping, how i can use the $InterpolationScheme
> feature
> > in .msh format in order to get the right distribution inside the elements
> > from the corresponding nodal values?
> >
> > i.e.
> > $InterpolationScheme
> > "name"
> > number-of-element-topologies
> > elm-topology
> > number-of-interpolation-matrices
> > num-rows num-columns value
> > ... ...
> > $EndInterpolationScheme
> >
> > Thank you in advance!
>
>
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