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67 lines
1.7 KiB
PHP

<?php
namespace Graphp\Algorithms;
use Graphp\Algorithms\BaseGraph;
use Fhaculty\Graph\Edge\Directed as EdgeDirected;
use Fhaculty\Graph\Edge\Undirected as EdgeUndirected;
/**
* Basic algorithms for working with the undirected or directed Graphs (digraphs) / Walks.
*
* @link http://en.wikipedia.org/wiki/Glossary_of_graph_theory#Direction
* @link http://en.wikipedia.org/wiki/Digraph_%28mathematics%29
*/
class Directed extends BaseDual
{
/**
* checks whether the graph has any directed edges
*
* This method is intentionally not named "isDirected()" (aka digraph),
* because that might be misleading in regards to empty and/or mixed graphs.
*
* @return boolean
*/
public function hasDirected()
{
foreach ($this->set->getEdges() as $edge) {
if ($edge instanceof EdgeDirected) {
return true;
}
}
return false;
}
/**
* checks whether the graph has any undirected edges
*
* This method is intentionally not named "isUndirected()",
* because that might be misleading in regards to empty and/or mixed graphs.
*
* @return boolean
*/
public function hasUndirected()
{
foreach ($this->set->getEdges() as $edge) {
if ($edge instanceof EdgeUndirected) {
return true;
}
}
return false;
}
/**
* checks whether this is a mixed graph (contains both directed and undirected edges)
*
* @return boolean
* @uses self::hasDirected()
* @uses self::hasUndirected()
*/
public function isMixed()
{
return ($this->hasDirected() && $this->hasUndirected());
}
}