Author: Uri Blass
Date: 15:07:10 02/26/01
Go up one level in this thread
On February 26, 2001 at 16:47:28, Christophe Theron wrote: <snipped> >>I disagree because a program may have special extensions that are productive >>only at long time control and you will never discover it without playing at long >>time control. > > >How do you know? I believe that there are special extensions that are productive at long time control and not at short time control. I believe that playing games against yourself in 10% of the thinkiong time and learning from the evaluations of the game is an extension that can be productive at long time control and not at short time control. I know no program that is using this extension today. The reason that the extension cannot be productive at short time control is simply because you cannot do good moves in games against yourself(if you have 1 second per move then you have only 1/10 second for playing against yourself and if you play 10 plies in your game against yourself you have only 1/100 second per move and this time control is usually not fast enough to play good moves). The extension can be productive at long time control and I have examples when giving the program to play against itself and learning from the games and only after it searching the root position can give better results than only giving the program to search the root position. > > > >>It is also possible to have pruning ideas that are productive only at long time >>control. > > >How do you know? > >In both cases (extensions and pruning), can you give examples? About pruning I think that if you have good pruning rules to identify illogical moves you can reduce the branching factor. When the price that you pay is the time that you need to evaluate if a move is an illogical move. If your branching factor is reduced by 10% when you are twice slower than it is clear that at long time control you can get an advantage when at short time control you are going to have problems. > > > >>It is possible that the same program is going to be the best at long time >>control and not the best at short time control because it use ideas to make it >>better at long time control. > > >That's something some people want you to believe. > >As for myself, and I think I have tried A LOT, I have never seen any idea that >makes a program better at long time controls if it does not make it better at >short time controls. > > > >>There is a diminishing returns from deeper search but inspite of the deminishing >>returns there are still cases when programs cannot find the right move in a long >>time. > > >We are talking about comparing programs against each other, not evaluating a >program in the absolute. > >There are cases where the best program will find a move that an inferior program >will not find. That's why even at long time controls the best program will still >win more. > >On the other hand there are less and less moves that the weaker program will not >find and that the best will find, as time controls increase. > >The result is that the gap between the two is smaller when time controls >increase (or processor power increases). > >That's the idea I'm currently trying to explain in simple terms. > > > >>I did not see a lot of draws in comp-comp tournament even when the hardware is >>fast and it sugggest that we are not close to see cases when bad programs have >>good chances against good programs even at long time control. > > >The number of draws between players of the same strength is not very high >anyway. You cannot expect the number of draws to be higher when programs get >closer to each other. You can show this by letting a program play against >itself. I can expect the number of draws to be bigger when the level is increasing because the programs are closer to play perfect game with no mistakes and I believe that a perfect game is a draw. Uri
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