Research and resolve one of the todo items

[FrancoisCarouge]

Is your feature request related to a problem? Please describe.
A number of to be done, to be resolved, or to be confirmed questions, features, or activities are marked in the codebase with the @todo documentation tags. Some of them are reported in the todo documentation list. There are all sorts of topics treated: C++, linear algebra, control theory. The goal of this story is to resolve one of them.

Describe the solution you'd like
No solution is prescribed as the to be done item is a pure open question to be researched, tested, benchmarked, weighted against solutions, or rationalized.