I like your use of the phrase "interpretation of Matrix Expressions." It makes it clear that we all probably have very different ideas for what Matrix Expressions should be. Hopefully there is a system which can handle a wide variety of needs.
My current branch is here https://github.com/mrocklin/sympy/tree/matrix_expr The main difference between our two interpretations is that I think of MatrixExpr's as being built up mainly of MatrixSymbol's rather than Matrix objects. Probably there is a nice way to make both feasible. For my GSOC project I needed Block Matrices so those are better developed. There is a blogpost demonstrating them here.<http://sympystats.wordpress.com/2011/07/19/multivariate-normal-random-variables/> On Fri, Jul 29, 2011 at 7:49 PM, Mateusz Paprocki <matt...@gmail.com> wrote: > Hi, > > On 16 July 2011 00:12, Ondrej Certik <ondrej.cer...@gmail.com> wrote: > >> On Fri, Jul 15, 2011 at 9:17 AM, Andy Ray Terrel <andy.ter...@gmail.com> >> wrote: >> > My suggestion would be to continue with the matrixify solution and >> > write functions to fix up the expression tree as need be. The whole >> > issue of making Add/Mul/Pow extensible is separate but the logic can >> > be transferred pretty easily. >> >> Exactly. Just get the job done, implement the necessary code, and >> whether or not Add/Mul/Pow classes can be extended is a separate >> issue, and I would suggest not to, to keep things simple in the core, >> so that we can refactor once we finish the assumptions refactoring. >> > > btw. Here is my interpretation of matrix expressions: > https://github.com/mattpap/sympy/tree/matrix_expr. Currently it doesn't > implement matrix expression arithmetic, but most certainly I'm not going to > allow a*M or A + B to "doit" by default, rather I will implement this within > expand() framework. What I need are semi evaluated matrix expressions, so > det(A^T) can be rewritten to det(A), but a*M must remain unevaluated. This > branch is very preliminary, there are no tests for the new stuff and I > didn't run tests so a few things may be broken > > >> >> Ondrej >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To post to this group, send email to sympy@googlegroups.com. >> To unsubscribe from this group, send email to >> sympy+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/sympy?hl=en. >> >> > Mateusz > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to sympy@googlegroups.com. > To unsubscribe from this group, send email to > sympy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
