Calculates peer review distribution (rater to peer assignments) More...

Collaboration diagram for ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution:

Public Member Functions
	__construct (array $user_ids, $num_assignments)
	ExcPeerReviewDistribution constructor. More...

	getUserOrder ()
	Get user order. More...

	getPeersOfRater ($user_id)
	Get peers of rater. More...

Protected Member Functions
	initDistribution ()
	Init distribution. More...

	randomUserOrder ($user_ids)
	Random user order. More...

Protected Attributes
	$user_ids = []

	$user_order = []

	$num_assignments

Detailed Description

Calculates peer review distribution (rater to peer assignments)

This is a simple algorithm, that ensures that each rater has $num_assignments peers to review and each peer has $num_assignments raters.

It starts by creating a random order of the users. After that it assignes the next $num_assignments users to a rater with index $i ($i+1 to $i+$numassignments) as peers. (Starting back from 0 if the counter exceeds the number of users)

Note that this will not include all theoretical combinations, but the randomization is good enough and the code much easier to maintain.

u0 u1 u2 u3 u4 (raters) u0 2 1 u1 1 2 u2 2 1 u3 2 1 u4 2 1 (peers)

Example above for 5 users and 2 assignments.

Author: Alexander Killing killi.nosp@m.ng@l.nosp@m.eifos.nosp@m..de

Definition at line 32 of file class.ExcPeerReviewDistribution.php.

Constructor & Destructor Documentation

◆ __construct()

ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution::__construct	(	array	$user_ids,
			$num_assignments
	)

ExcPeerReviewDistribution constructor.

Parameters

	int[]	$user_ids
int	$num_assignments

Definition at line 54 of file class.ExcPeerReviewDistribution.php.

References ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\$num_assignments, and ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\initDistribution().

     {
         $this->user_ids = array_values($user_ids);  // ensure numerical indexing
 
         // we cannot assign more users to a single user than count($user_ids) - 1
         $num_assignments = min($num_assignments, count($user_ids) - 1);
 
         // we cannot create a negative number of assignments
         $num_assignments = max($num_assignments, 0);
 
         $this->num_assignments = $num_assignments;
         $this->initDistribution();
     }

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Member Function Documentation

◆ getPeersOfRater()

ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution::getPeersOfRater ( $user_id )

Get peers of rater.

Parameters

int $user_id

Returns: int[]

Definition at line 108 of file class.ExcPeerReviewDistribution.php.

References $key, and ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\$num_assignments.

     {
         $peers = [];
         $key = array_search($user_id, $this->user_order);
         if ($key === false) {
             return [];
         }
         for ($j = 1; $j <= $this->num_assignments; $j++) {
             $peer_key = ($key + $j) % (count($this->user_order));
             $peers[] = $this->user_order[$peer_key];
         }
         return $peers;
     }

◆ getUserOrder()

ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution::getUserOrder ( )

Get user order.

Returns: array

Definition at line 97 of file class.ExcPeerReviewDistribution.php.

References ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\$user_order.

                                    : array
     {
         return $this->user_order;
     }

◆ initDistribution()

ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution::initDistribution ( )

protected

Init distribution.

Definition at line 71 of file class.ExcPeerReviewDistribution.php.

References ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\randomUserOrder().

Referenced by ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\__construct().

     {
         $this->user_order = $this->randomUserOrder($this->user_ids);
     }

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◆ randomUserOrder()

ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution::randomUserOrder ( $user_ids )

protected

Random user order.

Parameters

array

Returns: array

Definition at line 81 of file class.ExcPeerReviewDistribution.php.

References ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\$user_ids.

Referenced by ILIAS\Exercise\PeerReview\ExcPeerReviewDistribution\initDistribution().

                                                   : array
     {
         $order = [];
         while (count($user_ids) > 0) {
             $next = rand(0, count($user_ids) - 1);
             $order[] = $user_ids[$next];
             unset($user_ids[$next]);
             $user_ids = array_values($user_ids);    // re-index
         }
         return $order;
     }