>> >> IIUC, this is the "dequantised" version of X P, which is a perfectly >> well-defined quantum operator. "Obviously", (x * d_dx)(f) should >> return x * f'(x), but I see no way to make it work in your design. > > I noticed this too. It wouldn't really be possible to make an > "operator of operators", like a differential equation, because > something like (Derivative + f)(f)(x) would return Derivative(f(x), x) > + f(f(x)). I don't really see how one could do this with Lambdas > either, btw. >
The comparison with quantum mechanics is very flawed: X and P are both hermitian operators (the same mathematical object). However I was hasty in my first answer: x is a scalar field d_dx is a vector field x * d_dx should be a vector field This is related to the example that Aaron gave. I have a solution that works great if one assumes that the user will not do stupid things and that fails completely without this assumption. Please comment on this: https://krastanov.wordpress.com/2012/05/27/scalar-and-vector-fields-in-sympy-first-steps/ The part where I explain the construction of scalar and vector fields. I would like to know whether you are against this design. -- 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.
