On Saturday 13 December 2008 17:59:08 Aaron wrote:
> Hi all,
>
> First I'd like to give heartfelt thank to the sympy team. It's really
> a good package, and it helps me a lot as I'm working on some
> calculations of dynamic systems.
>
> I'm a newbie to sympy. The problem is, I do not know whether it is
> possible to get the derivative with respect to a function, not a
> symbol. The code is like this:
>
> t = Symbol("t")
> f = Function("f")
>
> theta = f(t)
> theta_dot = diff(theta,t,1)
> x = theta*theta_dot
> y = diff(x,theta_dot,1)
>
> Then the output is
> D(f(t)*D(f(t), t), D(f(t), t))
>
> However, my expected output should be "theta" or "f(t)" instead.
>
> Does anyone get an idea about this?
>
> Thanks in advance.
> Best regards
>Hello Aaron, I think this is not implemented yet, but there is a workaround, see Ondrej reply on: http://groups.google.com/group/sympy/browse_thread/thread/db3d1400be2743be/5cdfcf37996a9193 Please feel free to open an issue on: http://code.google.com/p/sympy/issues/list and, if you want, to send us a patch! Cheers, Riccardo --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
