> How do I make Maxima differentiate f(v,u) with respect
> of r-th element of v, df(v,u)/dv[r], i.e. take partial derivative in
v[r]?
Maxima doesn't recognize that v and v[i] are functionally related. So
diff(v,v[r]) gives zero. You can quote the diff to avoid this,
'diff(v,v[r]).
In theory, you could also declare that v depends on the v[r].
Unfortunately, there are two problems here: 1) there is no way of
declaring that v depends on v[r] for all r, only for particular r's; 2)
there is a bug (?) which causes an internal error if you do this. (I am
reporting this to the bug list.)
Does 'diff(v,v[r]) solve your problem? What is the larger problem you
are trying to solve?
-s