Sounds good- I will write the extended topological operators ( star(vertex) \ support(vertex) ; closure(cell) \ cone(cell) and U cone(support(edge)) ) and let you know if I have questions/run into issues!
-Chris On Thu, Aug 23, 2012 at 12:22 PM, Matthew Knepley <knepley at gmail.com> wrote: > On Thu, Aug 23, 2012 at 12:19 PM, Chris Eldred <chris.eldred at gmail.com> > wrote: >> >> I am working with a 2D unstructured mesh using sieve and I wanted to >> get some advice on how to determine adjacency relations using the >> topological operators provided by Sieve (cone, support, closure, >> star). I have figured out the following: >> >> Vertices for a given edge: cone(edge) >> Cells for a given edge: support(edge) >> >> Cells for a given vertex: star(vertex) \ support(vertex) >> Edges for a given vertex: support(vertex) >> >> Edges for a given cell: cone(cell) >> Vertices for a given cell: closure(cell) \ cone(cell) >> >> The set of edges associated with the cells for a given edge: U >> cone(support(edge)) - ie the union of the cones of the support of the >> edge >> >> Are there other topological operators that more naturally express >> these relations (especially the ones involving unions or complements)? > > > The only other builtin operations are meet and join. You are correct that > you > want to use union there. We could add routines like > > DMComplexGetConeUnion(dm, [p], &unionSize, &unionArray); > > but it was not clear that would do anything other than bloat the interface. > I > think the best way to procede is to write these convenience routines using > the lower level primitives, and move them into PETSc if they turn out to be > useful. I can help you write them. > > Matt > >> >> >> -- >> Chris Eldred >> DOE Computational Science Graduate Fellow >> Graduate Student, Atmospheric Science, Colorado State University >> B.S. Applied Computational Physics, Carnegie Mellon University, 2009 >> chris.eldred at gmail.com > > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener -- Chris Eldred DOE Computational Science Graduate Fellow Graduate Student, Atmospheric Science, Colorado State University B.S. Applied Computational Physics, Carnegie Mellon University, 2009 chris.eldred at gmail.com
