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<?php |
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namespace Graphp\Alg\Shortestpath; |
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use InvalidArgumentException; |
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use Heap\AddressableHeapInterface; |
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use Heap\Tree\PairingHeap; |
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use Graphp\GraphPathInterface; |
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use Graphp\GraphInterface; |
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use Graphp\Vertex\VertexInterface; |
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use Graphp\Util\Supplier; |
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use Graphp\Alg\Interfaces\SingleSourcePathsInterface; |
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/** |
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* Class DijkstraShortestPath |
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* |
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* @package Graphp\Alg\Shortestpath |
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*/ |
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class DijkstraShortestPath extends AbstractShortestPathAlgorithm |
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{ |
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/** |
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* The radius |
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* |
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* @var float |
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*/ |
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private $radius; |
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/** |
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* The heap supplier |
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* |
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* @var Supplier |
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*/ |
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private $heapSupplier; |
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/** |
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* Construct a new instance of the algorithm for the given graph |
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* |
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* @param GraphInterface $graph - the graph |
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* @param float $radius - the radius |
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* @param Supplier $heapSupplier - the heap supplier |
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*/ |
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public function __construct(GraphInterface $graph, float $radius = null, ?Supplier $heapSupplier = null) |
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{ |
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parent::__construct($graph); |
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if (!is_null($radius) && $radius < 0) { |
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throw new InvalidArgumentException("Radius must be non-negative"); |
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} |
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$this->radius = $radius ?? INF; |
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$this->heapSupplier = $heapSupplier ?? new Supplier(PairingHeap::class); |
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} |
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/** |
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* Find path between two vertices, if it exists. |
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* |
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* @param GraphInterface $graph - the graph |
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* @param VertexInterface $source - the source vertex |
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* @param VertexInterface $sink - the target vertex |
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* |
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* @return null|GraphPathInterface |
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*/ |
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public static function findPathBetween( |
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GraphInterface $graph, |
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VertexInterface $source, |
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VertexInterface $sink |
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): ?GraphPathInterface { |
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return (new DijkstraShortestPath($graph))->getPath($source, $sink); |
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} |
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/** |
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* Get the path from the source vertex to the target vertex |
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* |
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* @param VertexInterface $targetVertex - the source vertex |
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* @param VertexInterface $sink - the target vertex |
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* |
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* @return null|GraphPathInterface |
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*/ |
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public function getPath(VertexInterface $source, VertexInterface $sink): ?GraphPathInterface |
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{ |
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if (!$this->graph->containsVertex($source)) { |
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throw new InvalidArgumentException("Graph must contain the source vertex"); |
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} |
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if (!$this->graph->containsVertex($sink)) { |
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throw new InvalidArgumentException("Graph must contain the target vertex"); |
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} |
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if ($source->equals($sink)) { |
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return $this->createEmptyPath($source, $sink); |
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} |
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$it = new DijkstraClosestFirstIterator($this->graph, $source, $this->radius, $this->heapSupplier); |
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while ($it->hasNext()) { |
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$vertex = $it->next(); |
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if ($vertex->equals($sink)) { |
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break; |
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} |
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} |
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return $it->getPaths()->getPath($sink); |
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} |
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/** |
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* Compute all shortest paths starting from a single source vertex. |
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* |
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* @param VertexInterface $sourceVertex - the source vertex |
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* |
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* @return SingleSourcePathsInterface |
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*/ |
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public function getPaths(VertexInterface $source): SingleSourcePathsInterface |
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{ |
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if (!$this->graph->containsVertex($source)) { |
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throw new InvalidArgumentException("Graph must contain the source vertex"); |
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} |
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$it = new DijkstraClosestFirstIterator($this->graph, $source, $this->radius, $this->heapSupplier); |
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while ($it->hasNext()) { |
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$it->next(); |
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} |
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return $it->getPaths(); |
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} |
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} |
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bingo-soft /
graphp
