Right now, all algorithms compute first the production terms in one function call and the destruction terms (given the same states) in another function call directly afterward. However, it would be more efficient for some problems to have an API where the production and destruction terms are computed in a single function call.

For backward compatibility, we could wrap the two functions in one struct and call them one after the other. However, that would mean that we have to touch the out-of-place version a bit more (since we use some if statements in them). The in-place versions are fine since conservative and non-conservative systems are already separated.

What do you think about this, @SKopecz?