Author: Dann Corbit
Date: 12:23:56 06/20/01
Go up one level in this thread
On June 20, 2001 at 15:06:51, Côme wrote:
>On June 20, 2001 at 13:38:23, Dann Corbit wrote:
>
>>On June 20, 2001 at 13:08:10, Mark Young wrote:
>>[snip]
>>>Not by me, I don't have a problem with him being a GM, He teaches me chess on
>>>chess wise. I am not the one who has a problem with a 2484 elo GM, It was not I
>>>that suggest GM's are not GM's because they don't have a super high rating or
>>>because they are old.
>>
>>However, when they are old, it really does become more and more of a "paper
>>title" -- let's admit it. There is a huge inertia in ELO calculations. If you
>>play ten years, starting when you are ten years old, even if you are a prodigy,
>>it is doubtful you will start out above 1800. So, over a broad span of time,
>>your ELO figures in thousands of games at below (say) 2200. Imagine the
>>incredible performance you must achieve to pull the ELO over 2500! You must
>>play tremendous chess for a very long time to do it. Now, examine the reverse
>>side of the coin. Suppose you are a super GM who has played for decades. Maybe
>>for 20 years your ELO was over 2600. If your ELO is now at 2495, it means you
>>are playing 1800 chess.
>
>Hello !
>That is nonsense Dann and I hope you realise. A past 2600 player who have now
>2495 doesn't play 1800 chess.All your paragraphe is nonsense may be you should
>play chess before talking about it.
Sorry, but those are the facts. Suppose a super GM of 2600 ELO plays in a big
tournament and scores just 1% of the points. That's a rating difference of 800
ELO. 2600-800 = 1800. Here are the computations:
#include <stdio.h>
#include <math.h>
#include "uscf.h"
double provisional_rating(
double opponent_average_rating,
unsigned wins,
unsigned draws,
unsigned losses
)
{
double new_rating;
if (wins + draws + losses == 0)
new_rating = 0.;
else
new_rating = opponent_average_rating +
(400.0 * ((wins + 0.5 * draws) - (0.5 * draws + losses)) /
(wins + draws + losses));
return (double) (unsigned) (new_rating + 0.5);
}
double established_rating(
double old_rating,
double event_score,
double rating_difference,
char half_k_event,
double prize_amount,
unsigned event_level
)
{
double rating;
double k = old_rating >= 2400.0 ? 16.0 : old_rating >= 2100.0 ?
24.0 : 32.0;
if (half_k_event)
k *= 0.5;
rating = old_rating + k * (event_score - win_expectancy(rating_difference));
if (old_rating <= 2099.0 &&
rating >= 2100.0 &&
rating <= 2399.0)
rating = 2100.0 + (rating - 2100.0) * 0.75;
else if (old_rating >= 2100.0 &&
old_rating <= 2399.0 &&
rating <= 2099.0)
rating = 2100.0 * (rating - 2100.0) * 1.33;
else if (old_rating >= 2100.0 &&
old_rating <= 2399.0 &&
rating >= 2400.0 &&
rating <= 3000.0)
rating = 2400.0 * (rating - 2400.0) * 0.66;
else if (old_rating >= 2400.0 &&
old_rating <= 3000.0 &&
rating >= 2100.0 &&
rating <= 2399.0)
rating = 2400.0 * (rating - 2400.0) * 1.50;
return rating_floor_adj(old_rating, rating, prize_amount, event_level);
}
double win_expectancy(
double rating_difference
)
{
return 1.0 / (pow(10.0, (rating_difference / 400.0)) + 1.);
}
double rating_floor_adj(
double old_rating,
double new_rating,
double prize_amount,
unsigned event_level
)
{
char large_cash_prize = 0;
double temp_floor = old_rating - 200.0;
unsigned ltf = ((unsigned) (temp_floor)) % 100UL * 100UL;
if (old_rating >= 2400 || old_rating <= 100)
return new_rating;
if (old_rating < 1600)
ltf = 100;
if (old_rating < 2200 && prize_amount >= 1000)
large_cash_prize = 1;
else if (old_rating < 2300 && prize_amount >= 1500)
large_cash_prize = 1;
else if (old_rating < 2400 && prize_amount >= 2000)
large_cash_prize = 1;
if (large_cash_prize)
ltf = event_level;
return ltf > new_rating ? (double) ltf : new_rating;
}
unsigned long rating_floor(
double old_rating,
double new_rating,
double prize_amount,
unsigned event_level
)
{
char large_cash_prize = 0;
unsigned floor_value = (((unsigned) (old_rating - 200)) % 100U) *
100U;
if (old_rating >= 2400 || old_rating <= 100)
return (unsigned long) (new_rating + 0.5);
if (old_rating < 1600)
floor_value = 100;
if (old_rating < 2200 && prize_amount >= 1000)
large_cash_prize = 1;
else if (old_rating < 2300 && prize_amount >= 1500)
large_cash_prize = 1;
else if (old_rating < 2400 && prize_amount >= 2000)
large_cash_prize = 1;
if (large_cash_prize)
floor_value = event_level;
return floor_value;
}
const char *
describe_uscf_rating(
unsigned rating
)
{
char *rating_name;
if (rating > 2399)
rating_name = "Senior Master";
else if (rating >= 2200)
rating_name = "Master";
else if (rating >= 2000)
rating_name = "Expert";
else if (rating >= 1800)
rating_name = "Class A";
else if (rating >= 1600)
rating_name = "Class B";
else if (rating >= 1400)
rating_name = "Class C";
else if (rating >= 1200)
rating_name = "Class D";
else if (rating >= 1000)
rating_name = "Class E";
else if (rating >= 800)
rating_name = "Class F";
else if (rating >= 600)
rating_name = "Class G";
else if (rating >= 400)
rating_name = "Class H";
else if (rating >= 200)
rating_name = "Class I";
else
rating_name = "Class J";
return rating_name;
}
char string[32767];
int main(void)
{
double old_rating = 2600;
double event_score = .01;
double rating_difference = 100;
char half_k_event = 0;
double prize_amount = 100000;
unsigned event_level = 2500;
printf("%f\n", established_rating(
old_rating,
event_score,
rating_difference,
half_k_event,
prize_amount,
event_level));
return 0;
}
C:\tmp>uscf
2594.401040
His ELO has now dropped to 2594 from 1600. Can you see how badly he'd have to
tank it to drop to 2490? It would take a terrific number of tournaments getting
slaughtered every time.
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