[SciPy-Dev] 64-bit sparse matrix indices

[Nathaniel Smith]

On Fri, Dec 14, 2012 at 3:54 PM, Nathaniel Smith <njs at pobox.com> wrote:
> I guess this is a problem with option A as well, but at least existing
> code working on matrices that currently work, would keep working. OTOH
> option A also means that any future C/Fortran code has to be prepared
> to handle both cases. Not really a big deal when working in Cython,
> but I hear that some people still use other tools...

Actually on re-reading your mail, I guess the options you're suggesting are:

A: both 32- and 64-bit indices are possible, which is used depends on nnz
B: both 32- and 64-bit indices are possible, which is used depends on
python's architecture

?

So I withdraw the above comment -- both options require some sort of
annoying type parametrization, it isn't really a disadvantage of
option A.

-n

(Also surely it's only a 33% memory overhead compared to now? But
still I have the feeling people really do work with sparse matrices
right up to the limit of their available memory.)