How can I efficiently iterate over some values while making small
updates to a large state vector (in my actual application it's a
dictionary).For example, if I use `over` it's very slow because the
entire state vector is copied at each iteration:q)n...
Thanks for the suggestions, but I should have clarified two points
earlier:1. The actual calculation is path-dependent and non-trivial, so
the solution should work for any arbitrary function of the current state
and an element of the iterated vector....