fill for matrix multiplication

[Hong Zhang]

Manav,

I've enabled fill=PETSC_DFAULT for MatMatMultSymbolic().
We recommend using MatMatMult() instead of
MatMatMultSymbolic() and MatMatMultNumeric().

Thanks for reporting the problem,

Hong

On Sun, 18 Feb 2007, Barry Smith wrote:

>
>  Use 1.0 for dense matrices; it is ignored since dense matrices
> are always dense.
>
>    Barry
>
>
> On Sun, 18 Feb 2007, Manav Bhatia wrote:
>
> > Hi,
> >
> >  I am performing a matrix multiplication of two dense matrices with both
> > MatMatMult and MatMatMultTranspose.
> >  What do I choose a fill factor as? According to the definition in the
> > documentation: fiill = expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)).
> > So, If I have two full matrices A and B, I will get a full matrix as my
> > result. Hence, the fill factor will be 0.5. However, both these methods give
> > an error with a fill factor less than 1.0. Also, if I use PETSC_DFAULT as the
> > fill argument, it agains results in an error since its value is -2.
> >
> > Kindly help me with your advice here.
> >
> > Thanks
> > Manav
>
>