[ List Earliest Comments Only For Pages | Games | Rated Pages | Rated Games | Subjects of Discussion ]
Single Comment
Game Courier Ratings. Calculates ratings for players from Game Courier logs. Experimental.[All Comments] [Add Comment or Rating]Here is what the code look like after the files are read and the $wins
table is made. The $wins table is a two-dimensional array of pairwise
wins, for which $wins[$p1][$p2] is the number of times $p1 has beaten $p2.
Draws count as half wins for both players.
// Calculate various values needed for rating calculations
$players = array_keys($wins);
// Initialize all ratings to 1500
reset ($players);
foreach ($players as $pl) {
$gcr[$pl] = $gcr1[$pl] = $gcr2[$pl] = $gcr3[$pl] = $gcr4[$pl] = 1500;
}
// Count opponents and games of each player
reset ($players);
$pc = count($players);
for ($i = 0; $i < $pc; $i++) {
$p1 = $players[$i];
$opponents[$p1] = 0;
$gameswon[$p1] = 0;
$gameslost[$p1] = 0;
for ($j = 0; $j < $pc; $j++) {
$p2 = $players[$j];
if (($p1 != $p2) && ($wins[$p1][$p2] || $wins[$p2][$p1])) {
$opponents[$p1]++;
$gameswon[$p1] += $wins[$p1][$p2];
$gameslost[$p1] += $wins[$p2][$p1];
}
}
$gamesplayed[$p1] = $gameswon[$p1] + $gameslost[$p1];
$percentwon[$p1] = ($gamesplayed[$p1] > 0) ? (($gameswon[$p1] * 100) /
$gamesplayed[$p1]) : 0;
}
// Sort players
function psort ($p1, $p2) {
global $opponents, $gamesplayed;
if ($opponents[$p1] > $opponents[$p2])
return -1;
elseif ($opponents[$p1] < $opponents[$p2])
return 1;
elseif ($gamesplayed[$p1] > $gamesplayed[$p2])
return -1;
elseif ($gamesplayed[$p1] < $gamesplayed[$p2])
return 1;
elseif ($gameswon[$p1] > $gameswon[$p2])
return -1;
elseif ($gameswon[$p1] < $gameswon[$p2])
return 1;
else
return 0;
}
uasort ($players, 'psort');
// For each pair, calculate new ratings based on previous ratings.
// Use zig-zagging order to optimize interdependency between ratings.
for ($i = 1; $i < $pc; $i++) {
for ($j = $i; $j < $pc; $j++) {
$p1 = $players[$j-$i];
$p2 = $players[$j];
$n = $wins[$p1][$p2] + $wins[$p2][$p1];
if ($n == 0)
continue;
$stability1 = (abs($gcr1[$p1] - 1500) + 500) / 20;
$stability2 = (abs($gcr1[$p2] - 1500) + 500) / 20;
$reliability = (100 * $n) / ($n + 3);
$gap = abs($gcr1[$p1] - $gcr1[$p2]);
$lowpoint = min($gcr1[$p1],$gcr1[$p2]);
$midpoint = $lowpoint + $gap/2;
$gap = max($gap, 400);
$lowpoint = min($lowpoint, $midpoint - 200);
$pr1 = $lowpoint + ($wins[$p1][$p2] * $gap) / $n;
$pr2 = $lowpoint + ($wins[$p2][$p1] * $gap) / $n;
$gcr1[$p1] = (($stability1 * $gcr1[$p1]) + ($reliability * $pr1)) /
($stability1 + $reliability);
$gcr1[$p2] = (($stability2 * $gcr1[$p2]) + ($reliability * $pr2)) /
($stability2 + $reliability);
}
}
// Calculate all ratings again in reverse zig-zagging order.
for ($i = $pc-1; $i > 0; $i--) {
for ($j = $pc-1; $j > $i; $j--) {
$p1 = $players[$j-$i];
$p2 = $players[$j];
$n = $wins[$p1][$p2] + $wins[$p2][$p1];
if ($n == 0)
continue;
$stability1 = (abs($gcr2[$p1] - 1500) + 500) / 20;
$stability2 = (abs($gcr2[$p2] - 1500) + 500) / 20;
$reliability = (100 * $n) / ($n + 3);
$gap = abs($gcr2[$p1] - $gcr2[$p2]);
$lowpoint = min($gcr2[$p1],$gcr2[$p2]);
$midpoint = $lowpoint + $gap/2;
$gap = max($gap, 400);
$lowpoint = min($lowpoint, $midpoint - 200);
$pr1 = $lowpoint + ($wins[$p1][$p2] * $gap) / $n;
$pr2 = $lowpoint + ($wins[$p2][$p1] * $gap) / $n;
$gcr2[$p1] = (($stability1 * $gcr2[$p1]) + ($reliability * $pr1)) /
($stability1 + $reliability);
$gcr2[$p2] = (($stability2 * $gcr2[$p2]) + ($reliability * $pr2)) /
($stability2 + $reliability);
}
}
// Calculate all ratings again in half reverse zig-zagging order.
for ($i = 1; $i < $pc; $i++) {
for ($j = $pc-1; $j > $i; $j--) {
$p1 = $players[$j-$i];
$p2 = $players[$j];
$n = $wins[$p1][$p2] + $wins[$p2][$p1];
if ($n == 0)
continue;
$stability1 = (abs($gcr3[$p1] - 1500) + 500) / 20;
$stability2 = (abs($gcr3[$p2] - 1500) + 500) / 20;
$reliability = (100 * $n) / ($n + 3);
$gap = abs($gcr3[$p1] - $gcr3[$p2]);
$lowpoint = min($gcr3[$p1],$gcr3[$p2]);
$midpoint = $lowpoint + $gap/2;
$gap = max($gap, 400);
$lowpoint = min($lowpoint, $midpoint - 200);
$pr1 = $lowpoint + ($wins[$p1][$p2] * $gap) / $n;
$pr2 = $lowpoint + ($wins[$p2][$p1] * $gap) / $n;
$gcr3[$p1] = (($stability1 * $gcr3[$p1]) + ($reliability * $pr1)) /
($stability1 + $reliability);
$gcr3[$p2] = (($stability2 * $gcr3[$p2]) + ($reliability * $pr2)) /
($stability2 + $reliability);
}
}
// Calculate all ratings again in reverse half reverse zig-zagging order.
for ($i = $pc-1; $i > 0; $i--) {
for ($j = $i; $j < $pc; $j++) {
$p1 = $players[$j-$i];
$p2 = $players[$j];
$n = $wins[$p1][$p2] + $wins[$p2][$p1];
if ($n == 0)
continue;
$stability1 = (abs($gcr4[$p1] - 1500) + 500) / 20;
$stability2 = (abs($gcr4[$p2] - 1500) + 500) / 20;
$reliability = (100 * $n) / ($n + 3);
$gap = abs($gcr4[$p1] - $gcr4[$p2]);
$lowpoint = min($gcr4[$p1],$gcr4[$p2]);
$midpoint = $lowpoint + $gap/2;
$gap = max($gap, 400);
$lowpoint = min($lowpoint, $midpoint - 200);
$pr1 = $lowpoint + ($wins[$p1][$p2] * $gap) / $n;
$pr2 = $lowpoint + ($wins[$p2][$p1] * $gap) / $n;
$gcr4[$p1] = (($stability1 * $gcr4[$p1]) + ($reliability * $pr1)) /
($stability1 + $reliability);
$gcr4[$p2] = (($stability2 * $gcr4[$p2]) + ($reliability * $pr2)) /
($stability2 + $reliability);
}
}
// Average all four sets of ratings.
// This helps minimize the effects of using any order, making ratings more
homogonous.
for ($i = 0; $i < $pc; $i++) {
$p1 = $players[$i];
$gcr[$p1] = ($gcr1[$p1] + $gcr2[$p1] + $gcr3[$p1] + $gcr4[$p1]) / 4;
}
// Sort ratings
arsort ($gcr);
reset ($gcr);
// Print table of ratings
echo '
';
| Name | Userid | GCR | Percent won |
|---|---|---|---|
| %s | %s | %d | %.2f |