Action of vary() on a monomial (Cadabra2)

Question

I have problems varying a single monomial, see for instance

obj:= x_{m};
vary(obj, $x_{m} -> something$);

that gives error. Cadabra complains that it is not know how to vary that.

I currently circumvent this by using a dummy:

obj:= x_{m}\xi;
vary(obj, $x_{m} -> something$);

and then replacing $\xi\rightarrow1$. Is there a better way to do this ?

Answer 1

It's a bug, sorry (none of my test cases had such simple expressions :-( ). I have filed it as https://github.com/kpeeters/cadabra2/issues/57