>> in what sense is it symmetrical? > Just trying to get my head around this, it seems to me that what is meant is > : we provide a connectivity array, which is a square matrix describing the > connectivity relation "from cells to cells", i.e. connectitivy[i,j] == cell[i] adjoins cell[j] where i and j both range over the same cell dimension. In which case, it is just a symmetric matrix, meaning exactly that .. 'adjoins' is a symmetric relation ; or cell[i] adjoins cell[j] <--> cell[j] adjoins cell[i] (thus, the array == its own transpose, which is a definition of symmetry).
Well, conceptually maybe -- but that's not how anyone encodes the connectivity -- and it would be a huge, very sparse boolean array: number_of_cells X number_of_cells. The connectivity is encoded, in UGRID at least, as a length-number-of-cells array of (cell_number, cell_number, cell_number) triples (for a triangular mesh) I just looked at the UGRID docs, and oddly, even though the examples are tiny, we didn't seem to put the actual example arrays in, which does make it less clear than it could be :-( -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/153*issuecomment-882705622__;Iw!!G2kpM7uM-TzIFchu!iVfHPNJkj504LDAe9r_rjgGF7VJm1Y8-Mfe5HzC6rep5JLvZk61vKyJQZM7k2mk4lPJ90sX6UMA$ This list forwards relevant notifications from Github. It is distinct from [email protected], although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to [email protected].
