dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Oct 31, 2006 at 08:15:33AM +0100, Dag Lindbo wrote:
> Hi,
> 
> I'd like to know how the new mesh library handles moving verices in a
> mesh. This seems to not work:
> 
> // STRETCH MESH [0 1]x[0 1] -> [a b]x[a b] --------------------%%%
> void Mesh_fcns::meshTransformation(Mesh& mesh, real a, real b)
> {
>   for(VertexIterator n(mesh); !n.end(); ++n)
>     {
>       Vertex& vertex = *n;
>       vertex.point().x() = (b-a)*vertex.point().x() + a;
>       vertex.point().y() = (b-a)*vertex.point().y() + a;
>     }
> }
> 
> How to do it?
> /Dag

The point() function always returns a copy, so you need to use the
coordinates() function which also does not assume that you are in R^3
like point() does:

    for(VertexIterator v(mesh); !v.end(); ++v)
    {
      real* x = v->coordinates();
      x[0] = (b-a)*x[0] + a;
      x[1] = (b-a)*x[1] + a;
    }

This should work.

/Anders