[SciPy-dev] the current state and future directions of the sparse solvers

[Nils Wagner]

On Mon, 7 Apr 2008 19:55:33 +0200
  "Ondrej Certik" <ondrej at certik.cz> wrote:
> Hi,
> 
> these are probably mainly questions to Nathan. :)
> 
>First let me say that the new sparse functionality of 
>scipy is
> awesome, I really like it, it's just so easy and natural 
>to work with
> it. Thanks for your work on it.
> 
> Here I have some points:
> 
> 1) Why do you want to remove umfpack wrappers from 
>scipy? I suggest to
> leave wrappers in there (those can be BSD, cannot 
>they?), otherwise
> it will be much harder for scipy users to use umfpack 
>(they would have
> to install scikits too). If so, could this warning 
>message be removed?
> 
> scipy/sparse/linalg/dsolve/linsolve.py:20:
> 
> if isUmfpack and noScikit:
>    warn( 'scipy.sparse.linalg.dsolve.umfpack will be 
>removed,'
>          ' install scikits.umfpack instead', 
>DeprecationWarning )
> 
> 2) why was pysparse removed? are there any objections of 
>adding it
> among arpack and lobpcg solvers?
> 
> 3) sometimes I also use blzpack - are there any 
>objections if I
> implement it (if I find time of course) the same way 
>lobpcg and arpack
> is in there?
> 
> 4) I would love to see all available open source sparse 
>solvers and
> eigensolvers to be callable from scipy. Is this the 
>intention of
> scipy.sparse?
> 
> If this is the intention, I'd like to help with this too 
>-- there are
> other good open source solvers out there, for example 
>Primme (this one
> is GPLed, but that's not a problem, the wrappers could
> be in scipy, but users will install them themselves, or 
>from scikits).
> 
> 5) The documentation in the info.py files is quite good, 
>there is also
> some documentation at:
> 
> http://scipy.org/SciPy_Tutorial#head-c60163f2fd2bab79edd94be43682414f18b90df7
> 
> I have some improvements, for example
> scipy/sparse/linalg/eigen/info.py is missing the lobpcg, 
>the attached
> patch fixes that. 

lobpcg is currently disabled. See ticket
http://projects.scipy.org/scipy/scipy/ticket/630

BTW, a svd for sparse matrices would be nice, too.

Nils