dolfin team mailing list archive

[Johan Hake <hake.dev@xxxxxxxxx>]

On 01/28/2013 10:31 PM, Garth N. Wells wrote:
> On 28 January 2013 21:22, Anders Logg <logg@xxxxxxxxx> 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.
>>
> 
> Doesn't mean much to me. Can it be more descriptive?

Because it is a member of dofmap I did not include "dof" in the name.

But what with one of:

  vertex_to_dof_map
  tabulate_vertex_to_dof_map

>>> 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.
>>
> 
> I don't see the benefit of spreading it around. It should just belong to DofMap.

I am fine with both.

Johan

> Garth
> 
>> What is the relation to Function::compute_vertex_values?
>>
>> --
>> Anders
>>
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