protected function computeSimilarityMemory()
{
// data is already loaded by $this->loadDirectMatrix()
watchdog('recommender', "Computing similarity scores in memory. Could be CPU resource intensive. Please be patient");
$this->similarityMatrix = Matrix::correlation($this->directMatrix);
// cleanaup
$this->saveSimilarityMatrix($this->lowerbound);
$this->purgeOutdatedRecords('similarity');
if ($this->sim_pred == FALSE) {
$this->cleanupMemory();
}
}
protected function computeSimilarity()
{
// regardless of the type of preferenceMatrix, similarityMatrix will be a "SparseMatrix".
$this->similarityMatrix = Matrix::correlation($this->preferenceMatrix);
}
