get coordinates of a mesh vertex

[cyril]

Hello, what is an elegant way to get coordinates of a mesh vertex by its id? For the time being, I've implemented it like this:

typedef viennagrid::triangular_2d_mesh                            MeshType;
typedef  viennagrid::result_of::vertex<MeshType>::type            VertexType;
typedef viennagrid::result_of::point<MeshType>::type              PointType;
typedef viennagrid::result_of::id<VertexType>::type               VertexIDType;

unsigned int cell_point_ID = 5;

PointType p = viennagrid::find(mesh, VertexIDType(cell_point_ID))[0].appendix();

which looks awkward. Maybe I should use something else (vertex handle for a example) to get coordinates of a mesh vertex in a simple way, shoudn't I?

Thanks,
Cyril

[Karl Rupp]

Hi Cyril,

if you only have the vertex ID, but nothing else, then viennagrid::find() is all that is left. The reason is that vertex IDs do not have to be contiguous, so a direct array access is not always possible.

You last code line can be simplified to

PointType p = viennagrid::default_point_accessor(*viennagrid::find(mesh, VertexIDType(cell_point_ID));

Best regards,
Karli

[cyril]

Hello, Karli. Thanks for the answer, it seems this is what I was looking for.

Best regards,
Cyril

[cyril]

Actually, code

PointType p = viennagrid::default_point_accessor(*viennagrid::find(mesh, VertexIDType(cell_point_ID));

doesn't work.

It should be

PointType p = viennagrid::default_point_accessor(mesh)(*viennagrid::find(mesh, VertexIDType(cell_point_ID)));