/**
* Calculates the Jacard Similarity between the comparators' scalar attributes
* @param Comparator $a
* @param Comparator $b
* @return float Jaccard Similarity
*/
public function analyse(Comparator $a, Comparator $b)
{
$aa = $a->getScalarAttributes();
$ba = $b->getScalarAttributes();
if (count($aa) != count($ba)) {
throw new \LogicException("Cannot compute similary: attributes arrays are unequal");
}
if (count($aa) == 0 && count($ba) == 0) {
return 1;
}
//follows the convention that two empty objects are equal
$this->similarity = count(array_intersect_assoc($aa, $ba)) / count($aa);
return $this->similarity;
}
