Matrix expressions use new assumptions so assumptions are stored outside of the expression. There are good reasons for this. See distinction here http://matthewrocklin.com/blog/work/2013/02/05/Assuming/ . See example here http://scicomp.stackexchange.com/questions/74/symbolic-software-packages-for-matrix-expressions
Regarding Symbol in MatrixSymbol what we really need is a Basic that just holds a name/string. The current Symbol object does that plus a whole lot of other things that we don't need. Probably we just need a String(Basic) class or something similar. On Fri, Apr 25, 2014 at 9:18 AM, Clifford Wolf <[email protected]>wrote: > On Friday, April 25, 2014 5:04:47 PM UTC+2, Matthew wrote: >> >> Yeah, Aaron has been on me to remove the string from MatrixSymbol. My >> opinion is that we should allow non-basics in args. This will help us >> avoid recreating all of Python. I generally lose this argument. >> > > Well, I've only been reading sympy code for a day or so now, but I have to > agree with Aaron: I also don't like the ideas of non-basics in args.. > > Where I win though is with the claim that Symbol is way too magical and >> big to be used in Matrix Expressions. I'm going to claim that Matrix >> expressions are much simpler in design than the core. Part of this is the >> use of new assumptions. Injecting a Symbol, a huge source of magic, right >> in the center of matrix expressions makes my skin crawl a tiny bit. A good >> compromise is to make a Symbol object that is only a Symbol object, and not >> a scalar value with old assumptions info attached. >> > > You mean something like a MatrixSymbolName class with is_Symbol = True but > otherwise just a container for the one string? > > Are there any plans or existing infrastructure for storing assumptions on > matrices, such as is_positive_definite? When I suggested to store a Symbol > in MatrixSymbol.args[0] I also thought about maybe using this Symbol to > store assumptions regarding the matrix.. What are your thoughts on that? > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/b2a85eff-8e8c-4473-80c1-9fcda862cd49%40googlegroups.com<https://groups.google.com/d/msgid/sympy/b2a85eff-8e8c-4473-80c1-9fcda862cd49%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAJ8oX-HOt3bxjw8v3yt6B3KOCvr5V__hCrLru6x7nX_3UwgJuw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
