— Function File: [retval, pc, pf] = hinfsyn_chk (a, b1, b2, c1, c2, d12, d21, g, ptol)

Called by hinfsyn to see if gain g satisfies conditions in Theorem 3 of Doyle, Glover, Khargonekar, Francis, State Space Solutions to Standard H-2 and H-infinity Control Problems, IEEE TAC August 1989.

Warning: do not attempt to use this at home; no argument checking performed.

Inputs

As returned by is_dgkf, except for:

g

candidate gain level

ptol

as in hinfsyn

Outputs

retval

1 if g exceeds optimal Hinf closed loop gain, else 0

pc

solution of “regulator” H-infinity ARE

pf

solution of “filter” H-infinity ARE

Do not attempt to use this at home; no argument checking performed.