extern double provisional_rating(double opponent_average_rating,unsigned int wins,unsigned int draws,unsigned int losses);
extern double established_rating(double old_rating,double event_score,double rating_difference,char half_k_event,double prize_amount,unsigned int event_level);
extern double win_expectancy(double rating_difference);
extern double rating_floor_adj(double old_rating,double new_rating,double prize_amount,unsigned int event_level);
extern const char *describe_uscf_rating(unsigned int rating);