On 12/08/11 02:52, Johan Hake wrote: > Any objections to me merging this into trunk? > > > Will add unittest for all methods soonish. >
How soon? > > The code now resides in: > > > lp:~dolfin-core/dolfin/hake > > > Also, what would the best way to make it work in parallel. The distance > from all vertices in a mesh to the closest boundary might not be easy to > compute in Parallel as some vertices residing in one mesh might have the > closest distance in the mesh on another processor. > With difficulty. Sounds like an operation that is inherently not parallel. > > I am inclined to think that this is a bad side effect a user need to be > aware of when using this function in parallel. But then I know someone > who would disagree ;) > Add a line to throw an error in parallel until we figure out what's best. > > Another thing is that the present implementation takes a GenericVector > representing the return values of the distances at each vertex. Somthing > like: > > > distances = Function(V) > > > # Compute distance to Boundary for each vertex > > distance_computation = DistanceToBoundaryComputation(mesh) > > distance_computation.vertex_distances(distances.vector()) > > > In vertex_distances() I check that the local size of the passed vector > has the same size as the mesh.num_vertices() this gives an error when > running in parallel: > > > Expected a vector with the same local size as the number of vertices > (1449) in the mesh, got 1427 > > > Expected a vector with the same local size as the number of vertices > (1457) in the mesh, got 1441 > I would suggest not using Vector. It's really for linear algebra operations. Use std::vector or dolfin::Array. > > I suspect that it has something to do with shared vertices. How do I > access the "correct" number of vertices of a mesh partition and how do I > know which one is only owned by local mesh? > Boundary vertices are not 'owned' by any one processes. Dofs on a partition boundary are owned by one process. This information is available via the DofMap. > > I figure I have to look into ParallelData, which btw is not wrapped to > Python. We need to add it to dolfin_mesh.h. Will do later... > Don't rush to expose it. It shouldn't be required in user code. Garth > > Johan > > > On Wednesday August 10 2011 14:02:34 Johan Hake wrote: > >> Hello! > >> > >> I have created a class, DistanceToBoundaryComputation, similar to > >> IntersectionOperator, which takes a Mesh or a FacetFunction and compute > >> distances between any point and the closest point to the Boundary or a > >> subset of the boundary given by the FacetFunction. > >> > >> I have published it together with two demos, cpp and python to illustrate > >> some of its functions. > >> > >> lp:~johan-hake/dolfin/distance-to-boundary > >> > >> If the distances from each vertex is computed, will the result be similar > >> (not always equal) to the signed distance function, or the eikonal > >> equation, but it computes faster. > >> > >> I am not sure how this best can be integrated into the present dolfin. It > >> generates some data, like a BoundaryMesh, which it need to store, so it > >> might not be something we want to put into the Mesh class? If I use the > >> same lazy initialization that Andre used it might be possible. > >> > >> Please feel free to have alook at one of the demos to see it in action. > >> > >> Johan > >> > >> _______________________________________________ > >> Mailing list: https://launchpad.net/~dolfin > >> Post to : dolfin@lists.launchpad.net > >> Unsubscribe : https://launchpad.net/~dolfin > >> More help : https://help.launchpad.net/ListHelp > > > > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : dolfin@lists.launchpad.net > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
