dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Martin Sandve Alnæs wrote:
> On Wed, Jan 7, 2009 at 3:09 PM, Garth N. Wells <gnw20@xxxxxxxxx> wrote:
> > Anders Logg wrote:
> > > On Wed, Jan 07, 2009 at 02:49:17PM +0100, Johan Hake wrote:
> > > > On Wednesday 07 January 2009 14:28:09 Kent Andre wrote:
> > > > > It seems to me that the problem is that I have created two different
> > > > > FunctionSpaces that are actually the same and that the test
> > > > > in Function is a pointer check.
> > > > >
> > > > > One could of course make a better check based on e.g. a signature.
> > > > > This should be trivial to do. But I will end up with using
> > > > > a bit more memory than needed. Is this an acceptable solution ?
> > > > A check for the signature is not enough. Eventually we have to check for the
> > > > meshes in the two files being the same too.
> > > Maybe we should add a signature() function for meshes also that
> > > returns some kind of checksum for the mesh?
> > What's wrong with the approach that I presented? Just read the function
> > and extract from the function the FunctionSpace and the mesh?
> >
> > Garth
>
> Reading ten functions from file gives ten meshes in memory.

This is another issue. Kent's code was reading in one function only.

I have a dislike for reading and writing functions, mainly because of 
the use of signatures and the presence of pre-compiled finite elements 
in DOLFIN (the latter going against the spirit of automated generation). 
The most general approach would be to allow the construction of a 
Function with a FunctionSpace and a GenericVector. The user has to take 
some responsibility in making sure that the DofMap, Mesh, FiniteElement 
and GenericVector match. From a quick look at the code, the only extra 
thing that would be needed is a Function constructor that accepts a 
FunctionSpace and a GenericVector.

Garth



> Martin