[Gmsh] Bug with high-order adaptive visualization

[Christophe Geuzaine]

On 06/09/10 11:43, Marc Duflot wrote:
> Hi,
>
> I think there is a bug in the high-order adaptive visualization
> algorithm. No adaptation is performed if all the values are integers. It
> is illustrated with this simple example:
>

Hi Mark - It's not really a bug, more a limitation of the error 
estimator we use. To force subdivision, set the target error to a 
negative value.

> --8<---
>
> x1 = 1.01;
> x2 = 1.00;  // No adaptation if it is an integer value
>
> View "Quad" {
> SQ(
> 0.0,0.0,0.0,
> 1.0,0.0,0.0,
> 1.0,1.0,0.0,
> 0.0,1.0,0.0
> ){
> 0.0, 0.0, x1, 0.0
> };
> SQ(
> 2.0,0.0,0.0,
> 3.0,0.0,0.0,
> 3.0,1.0,0.0,
> 2.0,1.0,0.0
> ){
> 0.0, 0.0, x2, 0.0
> };
> INTERPOLATION_SCHEME
> {
>    {1/4,-1/4,-1/4, 1/4},
>    {1/4, 1/4,-1/4,-1/4},
>    {1/4, 1/4, 1/4, 1/4},
>    {1/4,-1/4, 1/4,-1/4}
> }
> { {0,0,0},
>    {1,0,0},
>    {0,1,0},
>    {1,1,0}
> };
> };
>
> View[0].AdaptVisualizationGrid = 1;
> View[0].MaxRecursionLevel = 5;
> View[0].TargetError = 0;
>
> --8<---
>
>
> By the way, there is a mistake in the example in section 8.1 of the
> manual. Lines 1 and 4 in the first brace of the interpolation scheme
> need to be swapped, like I did in the example above.
>
> Thanks,
> Marc
>


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine