On Fri, Jun 11, 2010 at 12:19 AM, Jason Grout <jason-s...@creativetrax.com> wrote: > On 6/11/10 1:50 AM, William Stein wrote: > >>> Copy on write *should* be rather easy to implement for matrices at least. > > William indicates otherwise in [1]. I can't think of an easy way to do it > either, so I'm really curious what how you think it would be easy. > >> >> Just out of curiosity, is this what would happen below with what you >> guys are envisioning >> for immutable copy on write matrices? >> > > [snip] > >> I think the above would be very, very confusing to me. If immutable >> matrices *act* as if they are fully mutable, but basically silently >> have completely different semantics, this will be confusing. > > I agree. I think my concerns would be taken care of if we just made the > top-level identity_matrix (and zero_matrix) function return a mutable matrix > (i.e., MM(1) or MM(0), rather than MM.one() or MM.zero()) > > I've posted a patch for doing this at > http://trac.sagemath.org/sage_trac/ticket/9212. It's ready for review.
Wait. Wasn't there a big discussion on sage-devel only maybe 3 months ago which was all about changing identity_matrix() to be *immutable*??? http://trac.sagemath.org/sage_trac/ticket/8276 > > Thanks, > > Jason > > [1] > http://groups.google.com/group/sage-devel/browse_frm/thread/1042edd11b3854b2 > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
