dolfin team mailing list archive

[Marie Rognes <meg@xxxxxxxxx>]

Anders Logg wrote:
> I've thought some more on the problem of mesh refinement and updating
> of Functions.
>
> The main problem seems to be the following:
>
>   mesh.refine()
>
> If we want to allow this, then we need to provide some kind of
> automated updating of functions and function spaces to the new mesh,
> since this call will otherwise destroy all function spaces and
> functions that refer to that mesh:
>
>   V = FunctionSpace(mesh, "CG", 1)
>   v = Function(V)
>   mesh.refine() # V and v no longer make any sense
>
> This gives us two options. Either we disallow refinement of a mesh
> without making a copy. Or we provide automated updating. I think we
> should do the latter.
>
>   

I think that I would appreciate both:

(a) Automated updating if mesh.refine()

and

(b) Functionality provided for updating functions to a new mesh if mesh 
= refine(mesh)


> What is needed compared to what we have now is to let a call to
> Mesh::refine trigger a call to FunctionSpace::update for all function
> spaces defined on the mesh, which in turn will trigger calls to
> Function::update for all functions defined on the function spaces.
>
> We can make the update functions private.
>
> Comments or objections? I think I can make this work.
>
>   

I can imagine that one would like to keep a copy of a function on the 
old mesh if
one compares solutions from different meshes. Then automated updating could
be somewhat suboptimal.

--
Marie



> --
> Anders
>   
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