dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Feb 12, 2010 at 05:42:26PM +0000, Garth N. Wells wrote:
>
>
> Anders Logg wrote:
> > On Fri, Feb 12, 2010 at 04:57:05PM +0100, Anders Logg wrote:
> >> On Fri, Feb 12, 2010 at 04:23:51PM +0100, Marie Rognes wrote:
> >>> I'm interesting in accessing the vector of a Function after mesh-refinement.
> >>> At the moment, I'm getting:
> >>>
> >>>    RuntimeError: *** Error: You are attempting to access a non-const
> >>>    vector from a sub-Function.
> >>>
> >>> Is this inevitable, a bug or a trigger-happy error message?
> >>>
> >>>    from dolfin import *
> >>>    mesh = UnitSquare(2,2)
> >>>    V = FunctionSpace(mesh, "CG", 1)
> >>>    u = Function(V)
> >>>    mesh.refine()
> >>>    u.vector()
> >> Looks like a bug. The function is not being refined but the mesh, the
> >> dofmap and the functionspace is refined. Might be related to the
> >> recent work on refinement.
> >
> > It should be fixed now. Someone had commented out register_object in
> > the Function constructor.
>
> I'm not too keen on all this magic. Harish I and have an adaptive solver
>  in which the function spaces are declared inside a loop and it's slowly
> leaking memory, but I can't figure out why. 'Magic' makes it really hard
> to figure out what's going on.

That's unfortunate. But the magic is necessary if we should allow
meshes to be refined. The other option would be to remove
mesh.refine() and always rely on

  new_mesh = refine(mesh)

And then explicitly create the new function spaces and project the
functions.

I'm not sure which implications that would have fore Marie's code.
Marie?

--
Anders

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