Xes
73154ae174
Fuente: https://github.com/chamilo/chamilo-lms/releases/download/v1.11.40/chamilo-1.11.40.zip sha256: 1cf4bf2cc7bae1ef1a1eff643235db1d552f78ddf4b6dd1e2d2dac9868679439 Snapshot independiente (rama huerfana); diffable vs 1.11.38. vendor incluido.
92 lines
2.7 KiB
PHP
92 lines
2.7 KiB
PHP
<?php
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namespace Graphp\Algorithms\MinimumSpanningTree;
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use Fhaculty\Graph\Edge\Base as Edge;
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use Fhaculty\Graph\Graph;
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use Fhaculty\Graph\Set\Edges;
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use Graphp\Algorithms\Base as AlgorithmBase;
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use SplPriorityQueue;
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/**
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* Abstract base class for minimum spanning tree (MST) algorithms
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*
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* A minimum spanning tree of a graph is a subgraph that is a tree and connects
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* all the vertices together while minimizing the total sum of all edges'
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* weights.
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*
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* A spanning tree thus requires a connected graph (single connected component),
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* otherwise we can span multiple trees (spanning forest) within each component.
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* Because a null graph (a Graph with no vertices) is not considered connected,
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* it also can not contain a spanning tree.
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*
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* Most authors demand that the input graph has to be undirected, whereas this
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* library supports also directed and mixed graphs. The actual direction of the
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* edge will be ignored, only its incident vertices will be checked. This is
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* done in order to be consistent to how ConnectedComponents are checked.
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*
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* @link http://en.wikipedia.org/wiki/Minimum_Spanning_Tree
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* @link http://en.wikipedia.org/wiki/Spanning_Tree
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* @link http://mathoverflow.net/questions/120536/is-the-empty-graph-a-tree
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*/
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abstract class Base extends AlgorithmBase
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{
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/**
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* create new resulting graph with only edges on minimum spanning tree
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*
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* @return Graph
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* @uses self::getGraph()
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* @uses self::getEdges()
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* @uses Graph::createGraphCloneEdges()
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*/
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public function createGraph()
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{
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return $this->getGraph()->createGraphCloneEdges($this->getEdges());
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}
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/**
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* get all edges on minimum spanning tree
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*
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* @return Edges
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*/
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abstract public function getEdges();
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/**
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* return reference to current Graph
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*
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* @return Graph
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*/
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abstract protected function getGraph();
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/**
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* get total weight of minimum spanning tree
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*
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* @return float
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*/
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public function getWeight()
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{
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return $this->getEdges()->getSumCallback(function (Edge $edge) {
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return $edge->getWeight();
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});
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}
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/**
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* helper method to add a set of Edges to the given set of sorted edges
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*
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* @param Edges $edges
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* @param SplPriorityQueue $sortedEdges
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*/
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protected function addEdgesSorted(Edges $edges, SplPriorityQueue $sortedEdges)
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{
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// For all edges
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foreach ($edges as $edge) {
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assert($edge instanceof Edge);
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// ignore loops (a->a)
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if (!$edge->isLoop()) {
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// Add edges with negative weight because of order in stl
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$sortedEdges->insert($edge, -$edge->getWeight());
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}
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}
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}
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}
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