On Dec 17, 2008, at 5:05 AM, Simon King wrote:
> > Hi all, > > On Dec 17, 10:07 am, Jason Grout <jason-s...@creativetrax.com> wrote: >> Could you give us a example of precisely what you would like to >> type and >> what you would like Sage to return? > > Of course I don't know what things olfa wants to solve. But my > impression from various previous posts about "solving systems with > symbolic matrices" was the following feature request: > > sage: solve([A*A.transpose()=MatrixSpace(QQ,n)(1)], A in MatrixSpace > (QQ,n)) > (or another meaningful syntax) > > Expected output: A parametrization of all orthogonal (nxn)-matrices. > > And this feature request can occur in two flavours: > a) n is a number, e.g., you specify n=5 and then ask sage to create > the above equations and solve them > b) n is symbolic; it is only assumed that n is a positive integer, and > sage is supposed to try and solve the system in full generality. > > While I think b) is not realistic, a) could in principle be > implemented (but AFAIK, it is not implemented yet, or am I mistaken?). There are certainly some things you can do with general matrices and vectors, but I think doing something like defining A as an nxm matrix and allowing various operations on it is a very useful thing. Mathematica has some support for this, but I don't think it has a general solve. I'd like to be able to define nxm matrices (and by extension vectors), apply transposes and take derivatives. This boils down to a special case non-commutative algebra (because it needs to support the transpose). Cheers, Tim. --- Tim Lahey PhD Candidate, Systems Design Engineering University of Waterloo http://www.linkedin.com/in/timlahey --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
