Issue 3928 in sympy: Disable diff_wrt on non-undefined Functions

2013-07-05 Thread sympy
Status: Valid Owner: Labels: Type-Defect Priority-Medium New issue 3928 by asmeu...@gmail.com: Disable diff_wrt on non-undefined Functions http://code.google.com/p/sympy/issues/detail?id=3928 We currently have In [6]: diff(cos(x), sin(x)) Out[6]: 0 But this confuses people, especially

Re: Issue 3928 in sympy: Disable diff_wrt on non-undefined Functions

2013-07-05 Thread sympy
Comment #1 on issue 3928 by asmeu...@gmail.com: Disable diff_wrt on non-undefined Functions http://code.google.com/p/sympy/issues/detail?id=3928 Although it might be cool to define it on specific ones, like re(), to get mathematical results. Or would that be too confusing against the

Re: Issue 3928 in sympy: Disable diff_wrt on non-undefined Functions

2013-07-05 Thread sympy
Updates: Cc: elliso...@gmail.com Comment #3 on issue 3928 by asmeu...@gmail.com: Disable diff_wrt on non-undefined Functions http://code.google.com/p/sympy/issues/detail?id=3928 Yeah, I know :) IIRC, I didn't want to do it for defined functions, but I think Brian was adamant that