dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, Sep 02, 2009 at 08:45:55AM +0200, Kent Andre wrote:
> On ti., 2009-09-01 at 17:59 +0100, Garth N. Wells wrote:
> >
> > Kent Andre wrote:
> > > On ti., 2009-09-01 at 17:16 +0100, Garth N. Wells wrote:
> > >> Kent Andre wrote:
> > >>> Hi,
> > >>> A.zero() is called both when reset_tensor is true and false
> > >>> in Assembler::init_global_tensor.
> > >>>
> > >>> The code is as follows:
> > >>>
> > >>> void Assembler::init_global_tensor(GenericTensor& A,
> > >>>                                    const Form& a,
> > >>>                                    UFC& ufc, bool reset_tensor)
> > >>> {
> > >>>   if (reset_tensor)
> > >>>   {
> > >>>     ...
> > >>>   }
> > >>>   else
> > >>>     A.zero();
> > >>> }
> > >>>
> > >>> Is this on purpose or is it a bug ?
> > >> The code is correct. 'A.zero()' zeroes the entries but preserves the
> > >> non-zero structure of the matrix.
> > >>
> > >> Garth
> > >>
> > >
> > > Then maybe reset_sparsity_pattern is a better name ?
> > >
> >
> > We could extend the assembler interface to
> >
> >    assemble(GenericTensor& A, const Form& a,
> >             bool reset_tensor_sparsity=true, bool add_values=false);
> >
> > I'm not a big fan of booleans though because they make no sense to the
> > reader in the calling code, e,g. what does
> >
> >    assemble(A, a, true, true);
> >
> > mean? We could use the parameter system instead.
> >
> > Garth
> >
>
>
> Does it matter if it is booleans ?
>
> Calling the assemble function, the way I want would be:
>
> E = assemble(mass, D, None, None, None, None, None, True, False)

If you're doing this in Python, then you could drop all the Nones and
just do

  E = assemble(mass, D, add_values=False)

But what is D?

Also, does it make sense to reset the sparsity pattern when not
zeroing the matrix? Resetting the sparsity pattern requires erasing
the values.

> Anyway, if it is ok, I update the assemble functions with both
> reset_tensor_sparsity and add_values.

Sounds ok to me.

--
Anders


> Kent
>
> Kent
>
>
>
>
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