Author: Vine Smith
Date: 11:26:15 05/20/01
Go up one level in this thread
On May 20, 2001 at 13:24:29, Christophe Theron wrote: >On May 20, 2001 at 04:25:41, Frank Phillips wrote: > >>On May 19, 2001 at 23:48:48, Christophe Theron wrote: >> >>>On May 19, 2001 at 23:37:31, Ratko V Tomic wrote: >>> >>>>>I'm extremely surprised that my creature managed to survive more >>>>> than 30 moves, given a 300 times speed handicap. >>>> >>>>The flip side is that the current programs running at some >>>>future machines at 300 GHz won't be able to crush the current >>>>programs on 1 GHz any more convincingly (in terms of how >>>>many moves the slower machine can hang on) than what happened >>>>in this matchup. >>>> >>>>This is the same effect that many players have experienced >>>>when upgrading their hardware to 2-3 times faster one and >>>>then being disapponted, after all the expense and hopes, >>>>when they can't even notice any difference in the perceived >>>>program strength (aginst humans). >>> >>> >>> >>>You are absolutely right. >>> >>>I think we are already beginning to experience the effects of dimishing returns >>>in chess on current hardware at long time controls. >>> >>> >>> >>> Christophe >> >>Would someone take the time to explain this simply and clearly, to me. I can >>understand that if you are already beating humans (or some other group of >>players) most of the time, then increasing the speed still means you are beating >>them most of the time and maybe a bit more, but until a machine can see _all_ >>there is to see how would it not improve by seeing more and how can you say >>(apriori) that it will improve only at a diminishing return? In other words, I >>can believe that results against a set of players is aysomtopic, tending towards >>100 percent, but do see why this is necessarily true of the game played by two >>otherwiseequally matched entities. > > > >In my opinion it has to do with the fact that in a given chess position the >number of moves is limited. Generally you have between 20 and 50 legal moves. > >From these moves, only an even more limited subset does not lead to an obvious >loss. > >And from this subset there is an even more limited subset of moves (2 or 3 >generally) that can be played, and chosing between them is a matter of >preference because the amount of computation needed to prove which one is better >is too big for any computer. > >So once you reach the stage where you can see which 2 or 3 moves are playable, >it would take an additional huge computation to see further. > >I think some chess programs on current computers at long time controls have >already reached this stage, and this is why is becomes increasingly difficult to >say which one is better. > >This is a very simplistic explanation which lacks mathematical support, I know, >but that's how I explain dimishing returns. > > > > Christophe Is it possible that there is also a problem with bad evaluations infecting whole branches in the tree of analysis? In Fritz vs. Gambit Tiger at Leiden, Fritz played 21.b4, shutting in its queen. Was this not a dreadful move? Yet, I had Fritz analyze after this point through 18 ply, and the evaluation was just +0.06 (after which it mysteriously halted analysis). And Tiger 14 has reached 20 ply looking at this same position, with an evaluation of just +0.46 after 21...Nc3 22.Rd3 Qf6 23.Kf1 Ne4 24.Bd4 Qf7 25.Bb2 g5 26.Rde3 Bf4 27.Bxe4 fxe4 28.Rxe4 Rxe4 29.Rxe4 Qxd5 30.Re7. Actually, the final position is lost for White after 30...Qd3+ 31.Re2 Qb1+ 32.Ne1 Bf5, but White doesn't need to play 30.Re7. The point is that neither program, given even 10-12 hours to think (on a PIII 850) appreciates the disastrous effects of White's missing queen. As poor evaluations like this clog up the search, all lines begin to look like one another, despite huge differences between them that would be clear to any human player examining these positions. Regards, Vine Smith
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.