dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Mon, Jan 17, 2011 at 04:30:23PM +0000, Garth N. Wells wrote:
>
>
> On 17/01/11 16:28, Anders Logg wrote:
> > The following doesn't seem to work in Python any longer:
> >
> > A = Matrix(10, 10)
> >
> > Is matrix initialization broken?
> >
>
> Probably not broken - more like
>
>   A = Matrix(10, 10)
>
> is not supported. Since a Matrix is in general sparse, it doesn't make
> sense to initialise it as above (some backends even insist on the
> sparsity being defined at construction).
>
> Garth

It would be good to allow simple initialization of a Matrix without
requiring to go through all the hassle of creating a SparsityPattern.

I generally don't think we should disallow certain operations just
because they are potentially slow. Some operations (like Matrix index
access) will only be performed for toy problems or while testing and
then speed is not very important (since the problem is small anyway).

--
Anders