[Dune] experience using superLU?

[Christian Engwer]

Hi Sreejith,

> I would like to know if anyone got experience using superLU
> solver. in particular i would like to know how to set up matrix in a
> format that superlu solver need using dune classes. I am trying to
> use the spmatrix available in dune. but the problem is that the
> SparseRowMatrix need to know the number of nonzeros per row in
> advance and

You only specify how much memory should be reserved:
 nz = max. number of non-zeros per row
 reserved space = nz * rows
Then you specify the entries in the matrix. If you don't use some of
these entries, then you waste a little bit of memory, but that is all.

> (i think it also assumes to have same no of nonzeros per row? if its
> not the case then how to use it?).

That is the case. But what is the problem? You will have some
non-zeros that store a value of zero for the boundary elements, but
the effect on the matrix size should be negligible. 

> there is a function CreateSupermatrix available but it give some
> problem to me where i have to specify the no of non-zeros per row.

You will receive a valid matrix, all uninitialized entries are set to
zero and the SuperMatrix get's created.

Could you go a little more into the details of your problem?

Cheers Christian