[petsc-dev] Why no SpGEMM support in AIJCUSPARSE and AIJVIENNACL?

[Jed Brown]

Karl Rupp <rupp at iue.tuwien.ac.at> writes:

>> Do you have any experience with nsparse?
>> 
>> https://github.com/EBD-CREST/nsparse
>> 
>> I've seen claims that it is much faster than cuSPARSE for sparse
>> matrix-matrix products.
>
> I haven't tried nsparse, no.
>
> But since the performance comes from a hardware feature (cache), I would 
> be surprised if there is a big performance leap over ViennaCL. (There's 
> certainly some potential for some tweaking of ViennaCL's kernels; but 
> note that even ViennaCL is much faster than cuSPARSE's spGEMM on average).
>
> With the libaxb-wrapper we can just add nsparse as an operations backend 
> and then easily try it out and compare against the other packages. In 
> the end it doesn't matter which package provides the best performance; 
> we just want to leverage it :-)

Indeed.  It'll be interesting to compare whenever someone has time to
add the interface.  I guess we could compare with a Matrix Market file
any time (using the driver distributed with nsparse).