dolfin team mailing list archive

[Johan Hake <hake.dev@xxxxxxxxx>]

On 01/28/2013 10:41 PM, Garth N. Wells wrote:
> On 28 January 2013 21:35, Johan Hake <hake.dev@xxxxxxxxx> wrote:
>> 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
> 
> This is ok.

I am fine with that.

> What does it do if it's not a P1 element?

Throws an error:

-------------------------------------------------------------------------
*** Error:   Unable to tabulating vertex to dofs.
*** Reason:  Can only tabulate dofs on vertices.
*** Where:   This error was encountered inside DofMap.cpp.
*** Process: 0
***
-------------------------------------------------------------------------

Johan


> Garth
> 
>>   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
>>>>
>>>> _______________________________________________
>>>> Mailing list: https://launchpad.net/~dolfin
>>>> Post to     : dolfin@xxxxxxxxxxxxxxxxxxx
>>>> Unsubscribe : https://launchpad.net/~dolfin
>>>> More help   : https://help.launchpad.net/ListHelp
>>