On 3/31/07, Mike Hansen <[EMAIL PROTECTED]> wrote:
>
> It works on 2.1.4 and 2.3 under Linux for me.
>
> On 3/31/07, Robert Miller <[EMAIL PROTECTED]> wrote:
> >
> > On both sage.math and my macbook, the following hangs:
> >
> > ----------------------------------------------------------------------
> > | SAGE Version 2.4, Release Date: 2007-03-25                         |
> > | Type notebook() for the GUI, and license() for information.        |
> > ----------------------------------------------------------------------
> >
> > sage: M = Matrix(FiniteField(2), [[1, 1, 1, 1, 0, 0, 0, 0, 0, 0]])
> > sage: M.row_space()
> >

Martin Albrecht completely changed the datatypes for mod-2 matrices in SAGE-2.4
to use Gregory Bard's M4Ri based code.   Then amazing timings like the following
happen:

sage: m = random_matrix(GF(2),1000)
sage: time m.echelonize()
CPU times: user 0.01 s, sys: 0.00 s, total: 0.01 s
Wall time: 0.01

sage: time n=m*m
CPU times: user 0.01 s, sys: 0.00 s, total: 0.01 s
Wall time: 0.01

Unfortunately, as seems to always be the case with new optimized linear algebra,
it appears to break on some simple cases:

sage: m = Matrix(FiniteField(2), [[1, 1, 1, 1, 0, 0, 0, 0, 0, 0]])
sage: time m.echelon_form()
Infinity !

This will be fixed in the next version of SAGE, either by disabling
m4ri or fixing the call to m4ri or m4ri itself.

 -- William

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