public function step(PathNode $previousNode, $exploredPaths = array())
{
// TODO: If previousNode is null, try to find the next node using the graph
// TODO: This should be fetched from the graph eventually
//$unexploredNeighbors = $previousNode->computeNeighbors();
// Make a random choice
/** @var PathNode $randomChoice */
$randomChoice = $previousNode->getRandomNextNode($previousNode->getUsedNodes());
// Check if we have reached a dead-end
if (is_null($randomChoice)) {
$this->nodeGraph->addPathLengthStatistic($previousNode);
return;
}
// Otherwise, prepare for the next step
$randomChoiceNode = new PathNode($this->dimensions, $randomChoice);
$randomChoiceNode->setParentNode($previousNode);
$this->step($randomChoiceNode);
}
/**
* Attempt to update the best path
*
* @param PathNode $node
*/
protected function updateBestPath(PathNode $node)
{
$pathLength = $node->getLength();
if ($this->bestPathLength < $pathLength) {
$this->bestPathLength = $pathLength;
$this->bestPath = $node;
}
}
/**
* Get the best path node or just null
*
* @throws Exception
* @return null|PathNode
*/
public function getBestPathTail()
{
// If we don't have any data, just return any
if (empty($this->bestPathLengths)) {
if ($this->initial) {
$newNode = new PathNode($this->dimensions, $this->getStringIdentifier());
$randomNode = new PathNode($this->dimensions, $newNode->getRandomNextNode());
$randomNode->setParentNode($newNode);
return $randomNode;
} else {
throw new Exception('This should not happen');
}
}
$bestSoFar = 0;
$bestPathIndex = null;
foreach ($this->bestPathLengths as $stringIdentifier => $pathLength) {
if ($pathLength > $bestSoFar) {
$bestSoFar = $pathLength;
$bestPathIndex = $stringIdentifier;
}
}
return $this->bestPaths[$bestPathIndex];
}
