[SciPy-dev] sparse matrix support status

[Nils Wagner]

On Fri, 30 Sep 2005 12:30:17 -0600
  Jeff Whitaker <jswhit at fastmail.fm> wrote:
> Nils Wagner wrote:
> 
>>
>> How about ARPACK 
>>(http://www.caam.rice.edu/software/ARPACK/) ?
>> It would be great to have eigs in scipy as well.
>>
>> Nils
>>
> 
> Nils:
> 
> Searching the scipy-user archives I found:
> 
> http://jrfonseca.dyndns.org/work/phd/
> 
> I think the Scipy developers have their hands full right 
>now.
> 
> -Jeff

But it doesn't seem to be optimal ...

  These bindings weren't generated with any automatic 
binding generation tool. Even though I initially tried 
both PyFortran and f2py, both showed to be inappropriate 
to handle the specificity of the ARPACK API. ARPACK uses a 
reverse communication interface where basically the API 
sucessively returns to caller which must take some update 
steps, and re-call the API with most arguments untouched. 
The intelligent (and silent) argument conversions made by 
the above tools made very difficult to implement and debug 
the most simple example. Also, for large-scale problems we 
wouldn't want any kind of array conversion/transposing 
happening behind the scenes as that would completely kill 
performance.

Therefore the bindings are faithfull to the original 
FORTRAN API and are not very friendly as is. Nevertheless 
a Python wrapper to these calls can easily be made, where 
all kind of type conversions and dummy-safe actions can be 
made.

> 
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