On 01/28/2013 11:08 PM, Anders Logg wrote: > On Mon, Jan 28, 2013 at 10:37:46PM +0100, Johan Hake wrote: >> On 01/28/2013 10:22 PM, Anders Logg wrote: >>> On Mon, Jan 28, 2013 at 10:10:40PM +0100, Johan Hake wrote: >>>> Hello! >>>> >>>> I have now added a method to DofMap, which tabulate a map between >>>> vertices and dofs. It will only work for DofMaps with dofs on vertices. >>>> So basically for any CG 1 FunctionSpaces and will raise error else wise. >>>> >>>> Usage: >>>> >>>> from dolfin import * >>>> import numpy as np >>>> mesh = UnitSquareMesh(10,10) >>>> V = VectorFunctionSpace(mesh, "CG", 1) >>>> u = Function(V) >>>> u.interpolate(Constant((1,2))) >>>> vert_values = np.zeros(mesh.num_vertices()*2) >>>> vert_values[V.dofmap().tabulate_vertex_map(mesh)] = \ >>>> u.vector().array() >>>> print vert_values >>>> >>>> In parallel the map will follow the local dofs. This means that some >>>> values in vert_values above will still be 0. The 0 values will then >>>> correspond to vertex values which are owned by another process. >>>> >>>> In C++ the method returns a std::vector<std::size_t>. >>>> >>>> Questions: >>>> Does the name "tabulate_vertex_map" work? >>> >>> Sounds ok. >>> >>>> Should a version of this method exist in other classes. FunctionSpace, >>>> Function (without the mesh argument of course)? >>> >>> Yes, would be good to have for convenience. >>> >>> What is the relation to Function::compute_vertex_values? >> >> compute_vertex_values works on any GenericFunction. However, for all >> Functions from CG 1 families I guess one could use this map to just >> tabulate the entries. > > What does the tabulate_vertex_map method do which > compute_vertex_values doesn't? Enable writing to dofs?
RTFC! ;) tabulate_vertex_map only computes a map based on the prior knowledge of the dofs coinciding with the vertices. compute_vertex_values are much more general and used element.interpolate_vertex_values to do the heavy lifting. I see tabulate_vertex_map as a convenience mapping for users who want their data on a vertex based format, or users who want data which resides on vertices into dolfin la structures. Johan _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
