Move Graph::hasEdgeParallel() to new Algorithm\Parallel

Author: clue

src/Parallel.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Fhaculty\Graph\Algorithm;
+
+use Fhaculty\Graph\Algorithm\BaseGraph;
+use Fhaculty\Graph\Edge\Base as Edge;
+use Fhaculty\Graph\Graph;
+
+/**
+ * Basic algorithms for working with parallel edges
+ *
+ * Parallel edges (also called multiple edges or a multi-edge), are two or more
+ * edges that are incident to the same two vertices. A simple graph has no
+ * multiple edges.
+ *
+ * @link http://en.wikipedia.org/wiki/Multiple_edges
+ */
+class Parallel extends BaseGraph
+{
+    /**
+     * checks whether this graph has any parallel edges (aka multigraph)
+     *
+     * @return boolean
+     * @uses Edge::hasEdgeParallel() for every edge
+     */
+    public function hasEdgeParallel()
+    {
+        foreach ($this->graph->getEdges() as $edge) {
+            if ($edge->hasEdgeParallel()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}