State Space Group Class

[gnakti]

Would it be possible to do something similar to the idea of Aggregation of Swing Equation, but for State-Space?
What I was thinking is you can move the logic, that is common for all state-space components, into a separate class, e.g., StateSpaceGroup. The StateSpaceGroup would encapsulate the discrete-state space model.

In terms of logic, StateSpaceGroup could take over the responsibility of defining the ABCD matrices and the state-space model numerical integration.

Originally posted by @georgii-tishenin in #175 (comment)