Adjusted initial parameters for maximum prediction power; in particular,

[foosball] / foosball.pm

diff --git a/foosball.pm b/foosball.pm
index a2b0d55b041ab4d8f6084f523dc8d680a31c4ecc..38722422caea742ec265373305a913c3e342b451 100644 (file)
--- a/foosball.pm
+++ b/foosball.pm
@@ -1,24 +1,36 @@
 use strict;
 use warnings;
 use DBI;
+use POSIX;
 
 package foosball;
 
+our $initial_rating = 1500.0;
+our $initial_rd = 400.0;
+our $c = 22.5;
+
 sub db_connect {
        my $dbh = DBI->connect("dbi:Pg:dbname=foosball;host=127.0.0.1", "foosball", "cleanrun", {AutoCommit => 0});
        $dbh->{RaiseError} = 1;
        return $dbh;
 }
 
+sub round {
+       my $x = shift;
+       return -round(-$x) if ($x < 0.0);
+       return POSIX::floor($x + 0.5);
+}
+
 sub find_single_rating {
        my ($dbh, $username, $limit) = @_;
+       $limit = "" if (!defined($limit));
        my ($age, $rating, $rd) = $dbh->selectrow_array('SELECT EXTRACT(EPOCH FROM (CURRENT_TIMESTAMP-ratetime)), rating, rd FROM single_rating WHERE username=? '.$limit.' ORDER BY ratetime DESC LIMIT 1',
                undef, $username);
        $rd = apply_aging($rd, $age / 86400.0);
 
        if (!defined($rating)) {
-               $rating = 1500;
-               $rd = 350;
+               $rating = $initial_rating;
+               $rd = $initial_rd;
        }
 
        return ($rating, $rd);
@@ -26,26 +38,19 @@ sub find_single_rating {
 
 sub find_double_rating {
        my ($dbh, $username, $limit) = @_;
+       $limit = "" if (!defined($limit));
        my ($age, $rating, $rd) = $dbh->selectrow_array('SELECT EXTRACT(EPOCH FROM (CURRENT_TIMESTAMP-ratetime)), rating, rd FROM double_rating WHERE username=? '.$limit.'ORDER BY ratetime DESC LIMIT 1',
                undef, $username);
        $rd = apply_aging($rd, $age / 86400.0);
        
        if (!defined($rating)) {
-               $rating = 1500;
-               $rd = 350;
+               $rating = $initial_rating;
+               $rd = $initial_rd;
        }
 
        return ($rating, $rd);
 }
 
-sub combine_ratings {
-       my ($rating1, $rd1, $rating2, $rd2) = @_;
-
-       my $rating_team = 0.5 * ($rating1 + $rating2);
-       my $rd_team = sqrt($rd1 * $rd1 + $rd2 * $rd2) / sqrt(2.0);
-       return ($rating_team, $rd_team);
-}
-
 sub create_user_if_not_exists {
        my ($dbh, $username) = @_;
        my $count = $dbh->selectrow_array('SELECT count(*) FROM users WHERE username=?',
@@ -53,20 +58,18 @@ sub create_user_if_not_exists {
        return if ($count > 0);
        $dbh->do('INSERT INTO users (username) VALUES (?)',
                undef, $username);
-       $dbh->do('INSERT INTO single_rating (username,ratetime,rating,rd) VALUES (?,CURRENT_TIMESTAMP,1500.0,350.0)',
-               undef, $username);
-       $dbh->do('INSERT INTO double_rating (username,ratetime,rating,rd) VALUES (?,CURRENT_TIMESTAMP,1500.0,350.0)',
-               undef, $username);
+       $dbh->do('INSERT INTO single_rating (username,ratetime,rating,rd) VALUES (?,CURRENT_TIMESTAMP,?,?)',
+               undef, $username, $initial_rating, $initial_rd);
+       $dbh->do('INSERT INTO double_rating (username,ratetime,rating,rd) VALUES (?,CURRENT_TIMESTAMP,?,?)',
+               undef, $username, $initial_rating, $initial_rd);
        return $dbh;
 }
 
-# c=8 => RD=50 moves to RD=350 over approx. five years
-our $c = 8;
-
+# $age is in days
 sub apply_aging {
        my ($rd, $age) = @_;
-       $rd = sqrt($rd*$rd + $c * $c * ($age / 86400.0));
-       $rd = 350.0 if ($rd > 350.0);
+       $rd = sqrt($rd*$rd + $c * $c * $age);
+       $rd = $initial_rd if ($rd > $initial_rd);
        return $rd;
 }
 
@@ -74,11 +77,11 @@ sub calc_rating {
        my ($rating1, $rd1, $rating2, $rd2, $score1, $score2) = @_;
        my $result = `/srv/foosball.sesse.net/foosrank $rating1 $rd1 $rating2 $rd2 $score1 $score2`;
        chomp $result;
-       my ($newr1, $newrd1) = split / /, $result;
+       my ($newr1, $newrd1, $likelihood) = split / /, $result;
 
        $newrd1 = 30.0 if ($newrd1 < 30.0);
 
-       return ($newr1, $newrd1);
+       return ($newr1, $newrd1, $likelihood);
 }
 
 sub calc_rating_double {