  We address H-infinity structured static state feedback and give a simple form
for an optimal control law applicable to linear time invariant systems with
symmetric and Hurwitz state matrix. More specifically, the control law as well
as the minimal value of the norm can be expressed in the matrices of the
system's state space representation, given separate cost on state and control
input. Thus, the control law is transparent, easy to synthesize and scalable.
Furthermore, if the plant possess a compatible sparsity pattern it is also
distributed. Examples of such sparsity patterns are included. Furthermore, we
give an extension of the optimal control law that incorporate coordination
among subsystems. We demonstrate by a numerical example that the derived
optimal controller is equal in performance to an optimal controller derived by
the riccati equation approach.
