/**
* Merge singleton nodes
*
* All equivalency classes which consist of just one nodes are considered
* singleton nodes. This method merges all maximum sets of singleton nodes,
* which share the same successors and precedessors.
*
* @param slAutomaton $automaton
* @return void
*/
protected function mergeSingletonNodes(slAutomaton $automaton)
{
$classes = array_keys($this->equivalenceClasses);
$classCount = count($classes);
for ($i = 0; $i < $classCount; ++$i) {
if (!isset($this->equivalenceClasses[$classes[$i]]) || count($this->equivalenceClasses[$classes[$i]]) > 1) {
// We only care for singletons
continue;
}
for ($j = $i + 1; $j < $classCount; ++$j) {
if (!isset($this->equivalenceClasses[$classes[$j]]) || count($this->equivalenceClasses[$classes[$j]]) > 1) {
// We only care for singletons
continue;
}
if ($automaton->getOutgoing($classes[$i]) === $automaton->getOutgoing($classes[$j]) && $automaton->getIncoming($classes[$i]) === $automaton->getIncoming($classes[$j])) {
$this->equivalenceClasses[$classes[$i]][] = $classes[$j];
unset($this->equivalenceClasses[$classes[$j]]);
$automaton->removeNode($classes[$j]);
}
}
}
}
