On Fri, Jul 8, 2011 at 4:00 AM, SherjilOzair <[email protected]> wrote: > There is something I'm doing as part of my project which maybe be > useful. I'm implementing a Matrix_ wrapper class which will wrap over > low-level matrices. Its being written to replace the current Matrix > class. Algorithmic code and user-level code is being separated into > different classes. Currently, we have three internal matrices, the > DenseMatrix( a modified form of the current Matrix class), DOKMatrix > and LILMatrix. These three are essentially Data internal matrices. > The MatrixSymbol can be another object that Matrix_ (later Matrix) > would use as internal. > > Of what I understand from this discussion about the Matrix Symbol, we > need to have an object that will be treated like a Matrix everywhere, > but without the internal data. Space is being made in the Matrix > module for such an object, but for it work nicely it needs to interact > nicely with Expr objects. If its a problem subclassing Expr and > friends, I'm +1 about making a separate codebase for matrix > expressions. It is, after all, a different algebra. > > I'm not very familiar with Expr, Add, etc. but I think a separate > algebra MatrixExpr, MatrixAdd, etc. could be developed by copy-pasting > some code from Expr, Add, and modifying according to need. I say 'copy- > paste' and not subclassing as the code would be need to be modified > much before it can work on matrices.
As has been discussed before, this is a bad idea. Just subclass Expr. Aaron Meurer > > Presently, I'm quite busy with this new encapsulation class Matrix_ > and can only think of working fulltime on MatrixSymbol after I've > merged in my work on DOKMatrix, LILMatrix and the ongoing work on > Matrix_. > > Matthew, you could set up a wiki page on 'matrix expressions' with > some example code in it. 'symbolic matrices' can mean a few number of > things, and is somewhat vague. It would be good if everyone could see > what sort of concrete things are expected from matrix expressions. > Approaches to implement Matrix Algebra, with pros and cons listed, > could be added there for discussion, suggestion and improvement. > > Regards, > Sherjil Ozair > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > 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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
