Well, the explanation is mundane. It is just a new change and the fact that _hashable_content is an expression instead of a tuple just slipped through.
Here is the fix https://github.com/sympy/sympy/pull/1437 On 22 July 2012 01:06, [email protected] <[email protected]> wrote: > The problem is that Subs has wrong _hashable_content() > I will send a pull request with a fix. > However I am still interested to know how this was never before > encountered. What was so special about this expression that it raised > an error? > > On 22 July 2012 01:02, [email protected] > <[email protected]> wrote: >>>>> (g(f(x))*Subs(Derivative(1, x), (x,), (1,))).diff(x) >> TypeError: object of type 'Derivative' has no len() >> >> Simplifying the expression any further makes the error go away (for >> instance removing the call to g). >> >> What perplexes me is how unremarkable the expression is. What can >> cause the error? Any idea? -- 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.
