On Tue, Apr 20, 2010 at 4:52 AM, Tim Lahey <tim.la...@gmail.com> wrote: > On Tue, Apr 20, 2010 at 7:42 AM, John Cremona <john.crem...@gmail.com> wrote: >> In summary: what is a sensible or desirable normalisation depends a >> lot on what the field is and what sort of mathematics you are doing! >> >> John > > Matlab has a bug in its eigen routines, at least in its eigenvalue > routines so I'm > assuming the eigenvector ones as well. I was giving it real, symmetric > positive > definite matrices and it gave me complex eigenvalues. > > If I recall correctly, Maple doesn't normalize its eigenvectors. I > don't see it as > necessary since if someone wants them normalized, they can do it. Just make > it clear in the docstring/documentation that the results returned > aren't normalized.
In contrast, I think answers in Sage should be canonically normalized whenever possible. This was one of the really good design principles that I learned from Allan Steel when working on Magma. > > Cheers, > > Tim. > > --- > Tim Lahey > PhD Candidate, Systems Design Engineering > University of Waterloo > http://www.linkedin.com/in/timlahey > > -- > 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
