Dear all,

I am looking for an efficient way to extract cell->node connectivity from face->cell and face->node connectivities.

Cell->node connectivity has node(vertex) numbers forming each cell.

Fluent's Gambit exports mixed element mesh data with face->cell and face->node connectivities only. But my fv solver and post-processing code require cell->node connectivity.

Any comments are welcome. Thank you.

There is a way here, but I am not sure if it's efficient enough:

(1) Looop faces: extract the face->cell information to cell->face information.

(2) Loop cells: get the cell->vertex information based on cell->face and face->vertex.

I am glad to hear some other more efficient way.

Ma

Invert the face->cell mapping to get the cell->face mapping. Then you can proceed to write the cell->node mapping. You may need to remove duplicate entries in the cell->node mapping. The simplest way is to use an array to carry a flag for duplicated nodes. You can also use a set if you prefer.

If your fv solver expects the nodes to be in a certain order, then the problem is a little more difficult. You will have to sort the cell->face mapping based on the way the faces are connected to each other. Once the cell topology can be inferred from the cell->face mapping, the nodes can be written out in whatever order the fv solver expects.

It should be an interesting exercise.

Good luck,

Madhukar

See the recent book by Rainald Lohner Applied CFD Techniques: An Introduction based on Finite Element Method.