public function getSolution()
{
$rootNode = new Node();
$initialNode = new Node(['active' => true, 'content' => $this->getInitialNodeContent(), 'optimistic_bound' => $this->getInitialNodeOptimisticBound(), 'pessimistic_bound' => $this->getInitialNodePessimisticBound()]);
$rootNode->addChild($initialNode);
$activeNodes = [$initialNode];
$currentBestFullNode = $initialNode;
$i = 0;
while ($activeNodes) {
$i++;
if ($i == 202) {
$a = 2;
}
$this->_logEvent('step_begin', ['root_node' => $rootNode, 'active_nodes' => $activeNodes, 'current_best_full_node' => $currentBestFullNode]);
$branchingNode = $this->_getBestNodeFrom($activeNodes);
$branchingNode->setActive(false);
$this->_logEvent('step_branching_begin', ['root_node' => $rootNode, 'branching_node' => $branchingNode]);
$children = $this->_generateChildrenOf($branchingNode);
$branchingNode->setChildren($children);
$this->_logEvent('step_branching_children_generated', ['root_node' => $rootNode, 'branching_node' => $branchingNode, 'children_generated' => $children]);
foreach ($branchingNode->getChildren() as $newNode) {
// if new node is better (or has better evaluation) than current best node
if ($this->_compareNodes($newNode, $currentBestFullNode) > -1 && $this->_nodeIsCorrect($newNode)) {
if ($this->_nodeIsCompleteSolution($newNode)) {
$currentBestFullNode = $newNode;
} else {
$newNode->setActive(true);
}
} else {
$newNode->setActive(false);
}
}
// get active nodes
// taking into account that nodes that were activated on previous steps (when they had best evaluation that solution on that step)
// CAN BECAME INACTIVE (due to solution on this step is better than their evaluations)
//
// also we deactivate them if they don't satisfy some special node limitations (for PDP they are 3D loading constraints)
$activeNodes = [];
foreach ($rootNode->getActiveChildrenRecursive() as $node) {
if ($this->_compareNodes($node, $currentBestFullNode) === 1) {
$activeNodes[] = $node;
} else {
$newNode->setActive(false);
}
}
$this->_logEvent('step_end', ['root_node' => $rootNode, 'active_nodes' => $activeNodes, 'children' => $children, 'current_best_full_node' => $currentBestFullNode]);
}
return $currentBestFullNode;
}
protected function _generateChildrenOf($node)
{
$result = [];
if (!$this->_nodeIsCompleteSolution($node)) {
$newPointSequences = $this->_generateNestedPointSequences($node);
foreach ($newPointSequences as $newPointSequence) {
if ($this->canLoad($newPointSequence)) {
$path = new Path(['points' => $newPointSequence]);
$newNode = new Node(['content' => $path]);
$newNode->setOptimisticBound($this->getEvaluator()->getBound($path, Evaluator::BOUND_TYPE_OPTIMISTIC));
$result[] = $newNode;
}
}
}
return $result;
}
