// become known so that to ensure that no transition is missed.
// NOTE: this is saved by the _hasIterationConverged() method
// defined in the FixedPointDirector, where it ensures that no receivers
// will change their status and until then an iteration is claimed
// complete.
Iterator inputPorts = controller.inputPortList().iterator();
while (inputPorts.hasNext()) {
IOPort inputPort = (IOPort) inputPorts.next();
if (!inputPort.isKnown()) {
return;