/**
* Forms the clusters by removing maximum weighted edges.
* performs breadth-first search to cluster the recipes.
*
* @param int $k queue size
* @param int $size number of recipes.
* @return array $cluster clusters of recipes.
*/
function formCluster($k, $size)
{
$this->cluster_heap->top();
$nodeQueue = new Queue($k);
$cluster_count = $size * CLUSTER_RATIO;
$cluster = array();
/*
Idea remove $cluster_count many weightiest edges from tree
to get a forest. As do this add to queue end points of
removed edges.
*/
for ($j = 0; $j < $cluster_count - 1; $j++) {
$max_edge = $this->cluster_heap->extract();
$cluster1_start = $max_edge->getStartVertex()->getLabel();
$cluster2_start = $max_edge->getEndVertex()->getLabel();
$this->adjMatrix[$cluster1_start][$cluster2_start] = -1;
$this->adjMatrix[$cluster2_start][$cluster1_start] = -1;
$nodeQueue->enqueue($cluster1_start);
$nodeQueue->enqueue($cluster2_start);
}
$queue = new Queue($k);
$i = 0;
// Now use Queue above to make clusters (trees in resulting forest)
while (!$nodeQueue->isEmpty()) {
$node = $nodeQueue->dequeue();
if ($this->vertices[$node]->isVisited() == false) {
$this->vertices[$node]->visited();
$cluster[$i][] = $this->vertices[$node]->getLabel();
$queue->enqueue($this->vertices[$node]->getLabel());
while (!$queue->isEmpty()) {
$node = $queue->dequeue();
while (($nextnode = $this->getNextVertex($node)) != -1) {
$this->vertices[$nextnode]->visited();
$cluster[$i][] = $this->vertices[$nextnode]->getLabel();
$queue->enqueue($this->vertices[$nextnode]->getLabel());
}
}
}
$i++;
}
return $cluster;
}