Vote:
∧
∧
∨
∨
x
(GroupID, 'Up'|'Down')
*/
public static function get_user_votes($UserID) {
if ((int)$UserID == 0) {
return array();
}
$UserVotes = G::$Cache->get_value("voted_albums_$UserID");
if ($UserVotes === false) {
$QueryID = G::$DB->get_query_id();
G::$DB->query("
SELECT GroupID, Type
FROM users_votes
WHERE UserID = $UserID");
$UserVotes = G::$DB->to_array('GroupID', MYSQL_ASSOC, false);
G::$DB->set_query_id($QueryID);
G::$Cache->cache_value("voted_albums_$UserID", $UserVotes);
}
return $UserVotes;
}
/**
* Returns an array with torrent group vote data
* @param string|int $GroupID
* @return array (Upvotes, Total Votes)
*/
public static function get_group_votes($GroupID) {
$GroupVotes = G::$Cache->get_value("votes_$GroupID");
if ($GroupVotes === false) {
$QueryID = G::$DB->get_query_id();
G::$DB->query("
SELECT Ups AS Ups, Total AS Total
FROM torrents_votes
WHERE GroupID = $GroupID");
if (!G::$DB->has_results()) {
$GroupVotes = array('Ups' => 0, 'Total' => 0);
} else {
$GroupVotes = G::$DB->next_record(MYSQLI_ASSOC, false);
}
G::$DB->set_query_id($QueryID);
G::$Cache->cache_value("votes_$GroupID", $GroupVotes, 259200); // 3 days
}
return $GroupVotes;
}
/**
* Computes the inverse normal CDF of a p-value
* @param float $GroupID
* @return float Inverse Normal CDF
*/
private function inverse_ncdf($p) {
/***************************************************************************
* inverse_ncdf.php
* -------------------
* begin : Friday, January 16, 2004
* copyright : (C) 2004 Michael Nickerson
* email : nickersonm@yahoo.com
*
***************************************************************************/
//Inverse ncdf approximation by Peter John Acklam, implementation adapted to
//PHP by Michael Nickerson, using Dr. Thomas Ziegler's C implementation as
//a guide. http://home.online.no/~pjacklam/notes/invnorm/index.html
//I have not checked the accuracy of this implementation. Be aware that PHP
//will truncate the coeficcients to 14 digits.
//You have permission to use and distribute this function freely for
//whatever purpose you want, but please show common courtesy and give credit
//where credit is due.
//Input paramater is $p - probability - where 0 < p < 1.
//Coefficients in rational approximations
$a = array(1 => -3.969683028665376e+01, 2 => 2.209460984245205e+02,
3 => -2.759285104469687e+02, 4 => 1.383577518672690e+02,
5 => -3.066479806614716e+01, 6 => 2.506628277459239e+00);
$b = array(1 => -5.447609879822406e+01, 2 => 1.615858368580409e+02,
3 => -1.556989798598866e+02, 4 => 6.680131188771972e+01,
5 => -1.328068155288572e+01);
$c = array(1 => -7.784894002430293e-03, 2 => -3.223964580411365e-01,
3 => -2.400758277161838e+00, 4 => -2.549732539343734e+00,
5 => 4.374664141464968e+00, 6 => 2.938163982698783e+00);
$d = array(1 => 7.784695709041462e-03, 2 => 3.224671290700398e-01,
3 => 2.445134137142996e+00, 4 => 3.754408661907416e+00);
//Define break-points.
$p_low = 0.02425; //Use lower region approx. below this
$p_high = 1 - $p_low; //Use upper region approx. above this
//Define/list variables (doesn't really need a definition)
//$p (probability), $sigma (std. deviation), and $mu (mean) are user inputs
$q = null; $x = null; $y = null; $r = null;
//Rational approximation for lower region.
if (0 < $p && $p < $p_low) {
$q = sqrt(-2 * log($p));
$x = ((((($c[1] * $q + $c[2]) * $q + $c[3]) * $q + $c[4]) * $q + $c[5]) *
$q + $c[6]) / (((($d[1] * $q + $d[2]) * $q + $d[3]) * $q + $d[4]) *
$q + 1);
}
//Rational approximation for central region.
elseif ($p_low <= $p && $p <= $p_high) {
$q = $p - 0.5;
$r = $q * $q;
$x = ((((($a[1] * $r + $a[2]) * $r + $a[3]) * $r + $a[4]) * $r + $a[5]) *
$r + $a[6]) * $q / ((((($b[1] * $r + $b[2]) * $r + $b[3]) * $r +
$b[4]) * $r + $b[5]) * $r + 1);
}
//Rational approximation for upper region.
elseif ($p_high < $p && $p < 1) {
$q = sqrt(-2 * log(1 - $p));
$x = -((((($c[1] * $q + $c[2]) * $q + $c[3]) * $q + $c[4]) * $q +
$c[5]) * $q + $c[6]) / (((($d[1] * $q + $d[2]) * $q + $d[3]) *
$q + $d[4]) * $q + 1);
}
//If 0 < p < 1, return a null value
else {
$x = null;
}
return $x;
//END inverse ncdf implementation.
}
/**
* Implementation of the algorithm described at http://www.evanmiller.org/how-not-to-sort-by-average-rating.html
* @param int $Ups Number of upvotes
* @param int $Total Number of total votes
* @return float Ranking score
*/
public static function binomial_score($Ups, $Total) {
if (($Total <= 0) || ($Ups < 0)) {
return 0;
}
$phat = $Ups / $Total;
$Numerator = ($phat + self::Z_VAL * self::Z_VAL / (2 * $Total) - self::Z_VAL * sqrt(($phat * (1 - $phat) + self::Z_VAL * self::Z_VAL / (4 * $Total)) / $Total));
$Denominator = (1 + self::Z_VAL * self::Z_VAL / $Total);
return ($Numerator / $Denominator);
}
/**
* Gets where this album ranks overall, for its year, and for its decade. This is really just a wrapper.
* @param int $GroupID GroupID of the album
* @param int $Year Year it was released
* @return array ('overall'=>, 'year'=>, 'decade'=>)
*/
public static function get_ranking($GroupID, $Year) {
$GroupID = (int)$GroupID;
$Year = (int)$Year;
if ($GroupID <= 0 || $Year <= 0) {
return false;
}
return array(
'overall' => Votes::get_rank_all($GroupID),
'year' => Votes::get_rank_year($GroupID, $Year),
'decade' => Votes::get_rank_decade($GroupID, $Year));
}
/**
* Gets where this album ranks overall.
* @param int $GroupID GroupID of the album
* @return int Rank
*/
public static function get_rank_all($GroupID) {
$GroupID = (int)$GroupID;
if ($GroupID <= 0) {
return false;
}
$Rankings = G::$Cache->get_value('voting_ranks_overall');
if ($Rankings === false) {
$QueryID = G::$DB->get_query_id();
G::$DB->query('
SELECT GroupID, Score
FROM torrents_votes
ORDER BY Score DESC
LIMIT 100');
$Rankings = self::calc_ranks(G::$DB->to_pair(0, 1, false));
G::$DB->set_query_id($QueryID);
G::$Cache->cache_value('voting_ranks_overall', $Rankings, 259200); // 3 days
}
return (isset($Rankings[$GroupID]) ? $Rankings[$GroupID] : false);
}
/**
* Gets where this album ranks in its year.
* @param int $GroupID GroupID of the album
* @param int $Year Year it was released
* @return int Rank for its year
*/
public static function get_rank_year($GroupID, $Year) {
$GroupID = (int)$GroupID;
$Year = (int)$Year;
if ($GroupID <= 0 || $Year <= 0) {
return false;
}
$Rankings = G::$Cache->get_value("voting_ranks_year_$Year");
if ($Rankings === false) {
$QueryID = G::$DB->get_query_id();
G::$DB->query("
SELECT GroupID, Score
FROM torrents_votes AS v
JOIN torrents_group AS g ON g.ID = v.GroupID
WHERE g.Year = $Year
ORDER BY Score DESC
LIMIT 100");
$Rankings = self::calc_ranks(G::$DB->to_pair(0, 1, false));
G::$DB->set_query_id($QueryID);
G::$Cache->cache_value("voting_ranks_year_$Year", $Rankings, 259200); // 3 days
}
return (isset($Rankings[$GroupID]) ? $Rankings[$GroupID] : false);
}
/**
* Gets where this album ranks in its decade.
* @param int $GroupID GroupID of the album
* @param int $Year Year it was released
* @return int Rank for its year
*/
public static function get_rank_decade($GroupID, $Year) {
$GroupID = (int)$GroupID;
$Year = (int)$Year;
if ($GroupID <= 0 || $Year <= 0) {
return false;
}
// First year of the decade
$Year = $Year - ($Year % 10);
$Rankings = G::$Cache->get_value("voting_ranks_decade_$Year");
if ($Rankings === false) {
$QueryID = G::$DB->get_query_id();
G::$DB->query("
SELECT GroupID, Score
FROM torrents_votes AS v
JOIN torrents_group AS g ON g.ID = v.GroupID
WHERE g.Year BETWEEN $Year AND " . ($Year + 9) . "
AND g.CategoryID = 1
ORDER BY Score DESC
LIMIT 100");
$Rankings = self::calc_ranks(G::$DB->to_pair(0, 1, false));
G::$DB->set_query_id($QueryID);
G::$Cache->cache_value("voting_ranks_decade_$Year", $Rankings, 259200); // 3 days
}
return (isset($Rankings[$GroupID]) ? $Rankings[$GroupID] : false);
}
/**
* Turn vote scores into vote ranks. This basically only sorts out tied ranks
*
* @param array $GroupScores array ( => ) ordered by Score
* @return array ( => )
*/
public static function calc_ranks($GroupScores) {
$Rankings = array();
$PrevScore = $PrevRank = false;
$Rank = 1;
foreach ($GroupScores as $GroupID => $Score) {
if ($Score === $PrevScore) {
$Rankings[$GroupID] = $PrevRank;
} else {
$Rankings[$GroupID] = $Rank;
$PrevRank = $Rank;
$PrevScore = $Score;
}
$Rank++;
}
return $Rankings;
}
}
?>