On Feb 1, 1:08 pm, John H Palmieri <jhpalmier...@gmail.com> wrote:
Hi John,
<SNIP>
> > Pari seems rather inefficient when the above sparse matrix requires
> > more than 2GB Ram to compute. The sparse matrix code needs a good
> > cleanup anyway.
>
> I agree, and I absolutely do not volunteer to do this. (I don't know
> anything about sparse linear algebra, and I have no desire to learn
> about it.) The dense code needs work, too. For example, the
> docstring for elementary_divisors in matrix_integer_sparse says
>
> IMPLEMENTATION: Uses linbox, except sometimes linbox doesn't
> work (errors about pre-conditioning), in which case PARI is
> used.
>
> [snip]
>
> 'linbox' -- use linbox (currently off, broken)
Can you default it to LinBox in your case and report if LinBox causes
trouble either by throwing an error or by producing wrong results? In
that case having the smallest example possible would be excellent to
go off to the Linbox people and start complaining. I wasn't even aware
that this issue existed in LinBox and it might have been fixed a while
ago. As mentioned previously the sparse LA isn't in the best shape.
> > I think generally using dense representations to compute operations
> > like rank is a mistake even though it is substantially faster in the
> > cases you see. But I also think this discussion should happen on sage-
> > devel anyway.
>
> And here it is...
Thanks.
> John
Cheers,
Michael
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