/**
* Given the course identificator, selects, randomly, 50% of the students enrolled in the course,
* who will be the ones receiving the personalized recommendations.
* "array_rand" function returns the randomly selected keys, not values, so, we have to construct
* manually the array with random users.
*
* @param int $courseid The course to select students from.
* @param int $year The year the given course belongs to.
*/
public function select_students($courseid, $year)
{
$coursestudents = $this->db->get_students_from_course($courseid);
$count = count($coursestudents);
$selectedstudentsindexes = array_rand($coursestudents, $count / 2);
$selectedstudents = array();
foreach ($selectedstudentsindexes as $selectedindex) {
$selectedstudent = $coursestudents[$selectedindex];
array_push($selectedstudents, $selectedstudent);
}
$this->db->insert_selections($selectedstudents, $courseid, $year);
}
