Allow ExecComps to be used as ODE Systems

[robfalck]

Summary of Issue

Allow callables that return an OpenMDAO system to be passed as the ODE to a Phase.

Issue Type

• Bug
• Enhancement
• Docs
• Miscellaneous

Description

Phase currently requires the ODE Class derived from system be passed to it as ode_class. This prevents the user from passing in ExecComps.

To allow ExecComps, the check logic just needs to be changed to allow a callable function where the phase is instantiated with ode=lambda num_nodes: om.ExecComp('y=x', x={'shape': num_nodes}, y={'shape': num_nodes}). The function will be expected to take the same keyword arguments as a System (num_nodes, as well as any given keyword arguments).

Example

TBD

Environment

Dymos 0.18.0