[petsc-users] Dense multiply Sparse

[Barry Smith]

   If B is 50% dense then store it in a dense format. It will be much faster and the extra memory is minimal.  Even 30% dense.

   Barry

On May 14, 2012, at 5:13 AM, Hui Zhang wrote:

> I have two matrices A and B stored in sparse format.  While A is really sparse, B is relatively
> dense (say non-zeros entries about 50%).  Now to multiply the two matrices, among 
> 
>      A*B 
> or 
>     (B^T * A^T)^T
> 
> which is better, or no big difference ?
> 
> Thanks!
>