rhodri-m / graph
A very simple implementation of a Graph data structure.
Requires
- php: >=5.6.30
Requires (Dev)
- phpmd/phpmd: @stable
- phpunit/phpunit: 5.7.*
- sebastian/phpcpd: *
- squizlabs/php_codesniffer: *
README
A very simple implementation of a Graph data structure.
Installation
Composer
It is highly recommended that you use composer to install this library.
Simply run composer require rhodri-m/graph
and use composer's supplied autoloader
(usually by adding
require __DIR__ . '/vendor/autoload.php';
at the top of your script).
Basic Usage
The Node
and Edge
classes are designed to be extended by your own if required, so you can use your own entities as nodes or edges within a graph structure. eg:
class Person extends \Graph\Node { [...] }
GraphContainer
is the recommended way of storing, adding, removing nodes and edges to ensure consistency.
Example
$maintainAdjacencyMatrix = true; $directed = true; $weighted = false; $graphCon = new \Graph\GraphContainer( $maintainAdjacencyMatrix, $directed, $weighted ); $node1 = new \Graph\Node(); $graphCon->addNode($node1); $node2 = new \Graph\Node(); $graphCon->addNode($node2); $node3 = new \Graph\Node(); $graphCon->addNode($node3); // add Edges by Node references $graphCon->addEdge($node2, $node3); $graphCon->addEdge($node3, $node1); $graphCon->addEdge($node2, $node1); // add Edge from node1 to node2 by (zero-indexed) ids $graphCon->addEdgeByIds(0, 1); echo "\nNumber of Nodes: " . count($graphCon->getNodes()); echo "\nNumber of Edges: " . count($graphCon->getEdges()); echo "\nAdjacency Matrix:\n"; print_r($adjacencyMatrix = $graphCon->getAdjacencyMatrix());
will output:
Number of Nodes: 3
Number of Edges: 4
Adjacency Matrix:
Array
(
[0] => Array
(
[0] =>
[1] => 1
[2] =>
)
[1] => Array
(
[0] => 1
[1] =>
[2] => 1
)
[2] => Array
(
[0] => 1
[1] =>
[2] =>
)
)
Outputting to graph file formats for use by other applications
We can export our graphs to data formats such as GML for use by other applications, such as Gephi:
$gmlOutput = new \Graph\Output\Gml(); $gmlOutput->writeToFile('testGraph.gml', $graphCon);
Exporting the very basic graph example above to Gephi gives:
It is also possible to assign labels and colours to nodes for use in external viewers:
$node1->name = "Node 1"; $node1->colour = 'FF8888';