[t.teschner]

I was wondering if anyone has a good source for learning about efficient algorithms that construct the connectivity information that is required in unstructured meshes (specifically, for a face-based solver, how to get the elements that are attached to each side of an element).

I am aware of the book of Lohner (Applied Computational Fluid Dynamics Techniques: An Introduction Based on Finite Element Methods), which talks exactly about that, I just find the explanation a bit brief and would have liked a bit more information.

I found another interesting approach here and here (same author), where the vertices of all faces are stored in some predefined order (here lexicographical) in an array so that entries which have the same vertices must share the same face (and so the element ID can be deduced from those two entries). This, however, still requires two nested loops over the array (in my understanding) and so is probably not as fast as the algorithm described by Lohner.

Apart from those and as stated in the opening, I am interested in algorithms (and preferably some explanations along with them) how to create said face-based data structure. Any sources would be appreciated.