diff options
Diffstat (limited to 'mbbsd/chc.c')
| -rw-r--r-- | mbbsd/chc.c | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/mbbsd/chc.c b/mbbsd/chc.c index 8b74709d..8ce25f3f 100644 --- a/mbbsd/chc.c +++ b/mbbsd/chc.c @@ -1,7 +1,8 @@ /* $Id$ */ -#include <math.h> #include "bbs.h" +extern const double elo_exp_tab[1000]; + enum Turn { BLK, RED @@ -805,6 +806,14 @@ myplay(int s, chcusr_t *user1, chcusr_t *user2, board_t board, board_t tmpbrd) return endgame; } +int round_to_int(double x) +{ + /* assume that double cast to int will drop fraction parts */ + if(x>=0) + return (int)(x+0.5); + return (int)(x-0.5); +} + /* * ELO rating system * see http://www.wordiq.com/definition/ELO_rating_system @@ -814,6 +823,8 @@ count_chess_elo_rating(chcusr_t *user1, chcusr_t *user2, double myres) { double k; double exp_res; + int diff; + int newrating; if(user1->rating < 1800) k = 30; @@ -826,8 +837,19 @@ count_chess_elo_rating(chcusr_t *user1, chcusr_t *user2, double myres) else k = 10; - exp_res = 1.0/(1.0 + pow(10.0, (user2->rating-user1->rating)/400.0)); - user1->rating += (int)floor(k*(myres-exp_res)+0.5); + //exp_res = 1.0/(1.0 + pow(10.0, (user2->rating-user1->rating)/400.0)); + //user1->rating += (int)floor(k*(myres-exp_res)+0.5); + diff=(int)user2->rating-(int)user1->rating; + if(diff<=-1000 || diff>=1000) + exp_res=diff>0?0.0:1.0; + else if(diff>=0) + exp_res=elo_exp_tab[diff]; + else + exp_res=1.0-elo_exp_tab[-diff]; + newrating = (int)user1->rating + round_to_int(k*(myres-exp_res)); + if(newrating > 3000) newrating = 3000; + if(newrating < 1) newrating = 1; + user1->rating = newrating; } static void |