/**
* Calculates OPTIMISTIC path bound for PDP permutation
*
* @param \Litvinenko\Combinatorics\Pdp\Path $path
* @param string $boundType
* @param array $additionalInfo
*
* @return float
*/
protected function _calculateBound($path, $boundType, array $additionalInfo = array())
{
$result = null;
// calculates only optimistic bounds
if ($boundType == self::BOUND_TYPE_OPTIMISTIC) {
$result = $this->getTotalDistance($path->getPoints());
}
return $result;
}
/**
* Stub for calculating OPTIMISTIC node bound for PDP
* NEEDED $additionalInfo content: array('parent_node' => <parent node>, 'total_point_count' => <number of gererating elements used for bound calculation>)
*
* @param \Litvinenko\Combinatorics\Pdp\Path $path
* @param string $boundType
* @param array $additionalInfo
*
* @return float
*/
protected function _calculateBound(\Litvinenko\Combinatorics\Pdp\Path $path, $boundType, array $additionalInfo = array())
{
$result = null;
// this stub calculates only optimistic bounds
if ($boundType == self::BOUND_TYPE_OPTIMISTIC) {
$points = $path->getPoints();
$parentNode = $additionalInfo['parent_node'];
// if parent node is empty, just return id of first point
if (!$parentNode->getContent()->getPoints()) {
$firstPoint = reset($points);
$result = (double) $firstPoint->getId();
} else {
// otherwise, return : parent bound PLUS sum: (<point 1 id> - <total_point_count>)^2 + (<point 2 id> - <total_point_count>)^2 + ...
$result = $parentNode->getOptimisticBound() + 1;
// we add 1 to be sure that child bound will be greater than parent one
$count = $additionalInfo['total_point_count'];
foreach ($points as $point) {
$result += pow($count / 2 - (double) $point->getId(), 2);
}
}
}
return $result;
}