get_topo_order_degopt

[jarlebring]

The degopt form has a natural topological order that makes the memory footprint smaller in comparison to the get_topo_order-function, by working row-by-row in how we usually write it. I suggest we implement

get_topo_order_degopt(k)

which returns a Vector{Symbol} corresponding to that topological order for a degopt graph with k multiplications. We may want to extract the order with a call to get_degopt_coeffs (in order to lessen the place the symbols are hardcoded).

[eringh]

First implementation only gives the order. Do we want the deallocation list as well? The pathwidth?

In such case: Do we also want some optimization that looks for coefficients that are 0 and works on early deallocation? Possibly in combination with some of the implemented compress functions.

[jarlebring]

There are several variants of pathwidth that would be relevant for us, since we can do "inplace update" (called smart lincomb recycle parent in the gen_code) in some generated languages which reduces the memory footprint. It sounds complicated to fit all pathwdith variants together properly, so I would advise against it.