Author: Uri Blass
Date: 09:19:35 02/27/02
Go up one level in this thread
On February 27, 2002 at 12:15:18, Uri Blass wrote: >On February 27, 2002 at 11:43:26, Sune Fischer wrote: > >>On February 27, 2002 at 11:07:36, Uri Blass wrote: >> >>>>>The rating is dependent in the opponet that the perfect player chooses to play. >>>> >>>>No it is not, look at the formula, it is a normal distribution. >>>> >>>>>The perfect player may get 100% against my program on p800 because my program is >>>>>a deteministic program that always does the same mistake so if you assume the >>>>>perfect player plays only against my program then the perfect player is going to >>>>>get infinite rating. >>>> >>>>Your program is deterministic by your own words, so must score even worse than >>>>one doing random moves. >>> >>>it is going to score worse than random moves against the perfect player but it >>>scores clearly better against a lot of other players. >> >>Actually if it is deterministic, it will not score very high on a chess server, >>someone will beat it once and repeat the game over and over and nick all its >>rating. This is why you need a book or something to randomize it just a little >>bit. >> >> >>>>>The perfect player may get 100% against a player with a rating of 2000 when the >>>>>same player is going to fail to get 100% against a player that is clearly weaker >>>>>but not deterministic. >>>> >>>> >>>>Please do not ignore the small differences in probability, they are important. >>>>A 2000 elo player may be beaten by 10^30:1 and a 1000 elo player by 10^35:1, it >>>>should all add up to the same rating for the perfect player, that is how the elo >>>>table works. >>> >>>The problem is that rating is something that is dependent on the opponents that >>>you play. >>> >>>The perfect player may get 100% against one player with rating 2000 and only >>>99.9999999999% against another player who has today lower rating based on the >>>rating system. >>> >> >> >>The perfect player will _not_ get 100%, that is point. If the perfect player >>scores 100% he will have an infinite rating nomatter what the elo is of his >>opponent. If he's playing a deterministic engine, this will actually happen, I >>don't know if this means the program has minus infinity or the opponent >>infinity, whatever it is a strange example. >>So, you must assume less than 100%, even against the worst possible opponent. >> >>>You cannot calculate rating for a player without knowing the opponents and their >>>rating. >> >>Actually you can in a way, you just find the elo-difference, it is expresed by: >>DeltaELO=-400*log(1/p-1) >>where p is the probability of a win. You just add the opponents rating to this >>elo. >> >>I'm not sure if that is the exact formula used for chess, but I think it is >>something similar. >> >> >>>My program may get worse rating than the random move generator if they play >>>enough games against the perfect player but if you give both of them to play >>>against beginners then it is going to get better rating. >> >>If it is deterministic, it will in principle lose all matches after it has lost >>just one, this will not happen to a random program. > >No >It is not going to lose all matches because not everybody tries to repeat wins. > >The random player does not try to repeat wins so it is not going to lose matches >against this player. > >There are also humans who do not try to repeat wins against deterministic >programs because they find it boring. > >Uri I can add that even not deterministic players may get 0% if they always fall in the same kind of trap. The opening book and the learning of the chess programs of today may not be enough to score more than 0% against the perfect player because there is finite number of book lines and the computer has finite memory. Uri
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