Hi Burcin, On Wed, Aug 5, 2009 at 7:25 AM, Burcin Erocal<bur...@erocal.org> wrote: >> (1) Breaks substitution: >.... > We could either use the existing CallableSymbolicExpressionRing > implementation and force the user to give names to the arguments, to > get something like:
I would appreciate if you implement a solution for this issue. >> Let me claim: Integrating an expression involving new symbolic >> derivative is at best EQUAL and often MORE computationally EXPENSIVE >> than its "diff" counterpart. > > Are you saying that if we stop evaluating (partial) derivatives, > integrating them would be easier? :) I said that in bold, it would be EXPENSIVE means it requires more computational steps. >> (4) Causes Maxima interface to break: >> http://trac.sagemath.org/sage_trac/ticket/6376 > > This is a serious bug in the maxima interface. It has nothing to do > with how we denote derivatives, if we use partial derivaties or > unevaluated ones. For the record, diff format derivative is NOT affected by this bug. >> (4) Gives mathematically non-sensical results: >> http://trac.sagemath.org/sage_trac/ticket/6465 > > This is also an independent problem. With recent changes in pynac, you > stated that you fixed this: Yep, and it is because you are now asking for derivative to be carried out w.r.t. a variable such as "x". I guess, you might agree that by these changes you have pointed out a deficiency in the pynac "D" derivative concept where derivative is specified by paramaters such as 0,1 compared to the "diff" concept where derivative is specified by variables such as "x", "y". > IIRC, you wrote that your implementation can coexist with the current > one in Sage. Why don't you submit your changes so people can try out > both approaches? Sure. I am waiting for the next Sage release as I want to avoid re-basing again. I have implemented this using pynac-0.1.9.a1 and sage-4.0.2. Given, you have now moved back to pynac-0.1.8.p2, I need to backport pynac changes and forward-port Sage changes. Cheers, Golam --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
