public function testGraphIrregular()
{
// 1 -> 2 -> 3
$graph = new Graph();
$v1 = $graph->createVertex(1);
$v2 = $graph->createVertex(2);
$v3 = $graph->createVertex(3);
$v1->createEdgeTo($v2);
$v2->createEdgeTo($v3);
$alg = new AlgorithmDegree($graph);
try {
$this->assertEquals(0, $alg->getDegree());
$this->fail();
} catch (UnexpectedValueException $e) {
}
$this->assertEquals(1, $alg->getDegreeMin());
$this->assertEquals(2, $alg->getDegreeMax());
$this->assertFalse($alg->isRegular());
$this->assertFalse($alg->isBalanced());
$this->assertEquals(0, $alg->getDegreeInVertex($v1));
$this->assertEquals(1, $alg->getDegreeOutVertex($v1));
$this->assertEquals(1, $alg->getDegreeVertex($v1));
$this->assertFalse($alg->isVertexIsolated($v1));
$this->assertFalse($alg->isVertexSink($v1));
$this->assertTrue($alg->isVertexSource($v1));
$this->assertEquals(1, $alg->getDegreeInVertex($v2));
$this->assertEquals(1, $alg->getDegreeOutVertex($v2));
$this->assertEquals(2, $alg->getDegreeVertex($v2));
$this->assertFalse($alg->isVertexIsolated($v2));
$this->assertFalse($alg->isVertexSink($v2));
$this->assertFalse($alg->isVertexSource($v2));
$this->assertEquals(1, $alg->getDegreeInVertex($v3));
$this->assertEquals(0, $alg->getDegreeOutVertex($v3));
$this->assertEquals(1, $alg->getDegreeVertex($v3));
$this->assertFalse($alg->isVertexIsolated($v3));
$this->assertTrue($alg->isVertexSink($v3));
$this->assertFalse($alg->isVertexSource($v3));
}
/**
* check whether this graph has an eulerian cycle
*
* @return boolean
* @uses ConnectedComponents::isSingle()
* @uses Degree::getDegreeVertex()
* @todo isolated vertices should be ignored
* @todo definition is only valid for undirected graphs
*/
public function hasCycle()
{
$components = new ConnectedComponents($this->graph);
if ($components->isSingle()) {
$alg = new Degree($this->graph);
foreach ($this->graph->getVertices() as $vertex) {
// uneven degree => fail
if ($alg->getDegreeVertex($vertex) & 1) {
return false;
}
}
return true;
}
return false;
}
