On Tue, Jul 31, 2012 at 4:55 PM, Guru Devanla <[email protected]> wrote: > Based on the discussion so far, it seems that the opinion is current Tr > module should be moved to sympy/physics/quantum. Matt, per you suggestion do > you plan to add a simple Trace under MatrixExpressions, in that case? > > Also, can I leave the name of the module the way it is now or should we > change to name to reflect that it belongs to the physics/quantum module.
If you're worried about compatibility, changing the path breaks just as much as changing the file name, so you might as well change it (both will break exact path imports). Aaron Meurer > > I plan to work on this item this week and wrap it up based on whatever > decision is made. > > Regards > Guru > > > > On Thursday, July 12, 2012 5:34:22 PM UTC-5, Matthew wrote: >>> >>> Yes, the concept is quite subtle and not used (as far as I know) >>> outside the context of quantum mechanics (where it is used a lot). I >>> thought about having separate Trace and PartialTrace classes, but from >>> the user API standpoint, they are really the same thing. >>> >>> Trace = Partial Trace over all indices >> >> >> The immediate issue I see if this goes into MatrixExprs is that >> PartialTrace is a MatExpr while Trace is an Expr/Scalar. It's not easy to >> have a class that is both at the same time. If we do this then my approach >> would be to make both classes and have PartialTrace(arg, indices) yield a >> new Trace object on object creation when indices == all_indices. >> >> However, if partial traces are rarely used outside of quantum then maybe >> it makes sense to just keep them in quantum. A lot of the code in Guru's PR >> doesn't seem to apply to the MatrixExpr case (namely the tensor product >> stuff). MatrixExpressions is pretty restricted to linear algebra and not >> multi-linear algebra. I'm inclined to keep it this way. I think that an >> attempt to generalize the current module will result in an ugly solution. >> >> I think that this stuff should probably live in quantum until we get >> around to a Tensor expressions module. >> >> I think that I should make a simple Trace for MatrixExpressions and that >> the more sophisticated partial-trace on tensor-products code should move >> from sympy/core to sympy/physics/quantum for now. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/sympy/-/APU5J_H7v3UJ. > > 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.
