public function getVerticesChildren(Vertex $vertex)
{
$vertices = $vertex->getVerticesEdgeTo();
if ($vertices->hasDuplicates()) {
throw new UnexpectedValueException();
}
return $vertices;
}
protected function getVerticesAdjacent(Vertex $vertex)
{
if ($this->direction === self::DIRECTION_FORWARD) {
return $vertex->getVerticesEdgeTo();
} elseif ($this->direction === self::DIRECTION_REVERSE) {
return $vertex->getVerticesEdgeFrom();
} elseif ($this->direction === self::DIRECTION_BOTH) {
return $vertex->getVerticesEdge();
} else {
throw new DomainException('Should not happen. Invalid direction setting');
}
}
/**
*
* calculates the recursive algorithm
*
* fills $this->visitedVertices
*
* @param Vertex $vertex
*/
private function recursiveDepthFirstSearch(Vertex $vertex, array &$visitedVertices)
{
// If I didn't visited this vertex before
if (!isset($visitedVertices[$vertex->getId()])) {
// Add Vertex to already visited vertices
$visitedVertices[$vertex->getId()] = $vertex;
// Get next vertices
$nextVertices = $vertex->getVerticesEdgeTo();
foreach ($nextVertices as $nextVertix) {
// recursive call for next vertices
$this->recursiveDepthFirstSearch($nextVertix, $visitedVertices);
}
}
}
protected function visit(Vertex $vertex, array &$visited, array &$tsl)
{
$vid = $vertex->getId();
if (isset($visited[$vid])) {
if ($visited[$vid] === false) {
// temporary mark => not a DAG
throw new UnexpectedValueException('Not a DAG');
}
// otherwise already marked/visisted => no need to check again
} else {
// temporary mark
$visited[$vid] = false;
foreach (array_reverse($vertex->getVerticesEdgeTo()->getVector()) as $v) {
$this->visit($v, $visited, $tsl);
}
// mark as visited and include in result
$visited[$vid] = true;
$tsl[$vid] = $vertex;
}
}
