Aaron S. Meurer wrote: > Well, Chris is right that the problem directly is issue 2049, but > actually, the reason that you get the problem is that what you are > trying to do is not yet supported, namely, taking derivatives with > respect to functions. See issue 1816. > > So a workaround will have to be to temporarily replace x(t) with just > the symbol x (or some other dummy symbol), until that becomes > implemented.
OK, thanks so far. However, I think just replacing x(t) by a symbol does serve for me since I want to take the total derivative with respect to t. Additionally, it seems to me that taking derivatives with respect functions is supported at least partially. E.g. In [3]: f(x(t)).diff(t) Out[3]: D(f(x(t)), x(t))*D(x(t), t) works as expected. Meanwhile I found a workaround for my problem: Replacing D(f(x(t)), x(t)) by a symbol (say z), perform the substitution that I actually want to do, i.e., replacing D(x(t), t) by the Symbol a and finally resubstitute z by D(f(x(t)), x(t)) Of course it would be much better if this would work directly. BTW is there a notifying mechanism if an issue gets solved? Thanks again. Bastian. -- 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.
