Author: Uri Blass
Date: 13:00:32 05/20/01
Go up one level in this thread
On May 20, 2001 at 15:35:17, Uri Blass wrote: >On May 20, 2001 at 14:26:15, Vine Smith wrote: > >>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. > >I prefer black's position after b4 but >I am not sure about the disastrous effect of white missing queen > >Following the main line of chess programs is a bad idea because it is known that >the end of the main line is often wrong. > >The real test is to give programs to play. >Tiger beated Fritz in the game but it is not a convincing proof because it is >only one game. > >It is better to play games at slower time control between programs and only if I >see that black wins all the games I will say that black is probably winning. >Before seeing it I can only say that I prefer black but I am not sure if black >has enough to win the game. > > >I think that evaluating it more than christophe does may cause problems even if >black can win the specific position because sacrificing for the idea of putting >the queen at this situation is risky because the queen can finally escape by >ideas like a4. > >Finally I can add that it seems that 8 processors may help Fritz to avoid the >problem > >Here is some analysis of Deep Fritz on PIII800(64 mbytes) > >Fritz - Gambit Tiger 2.0 >r3r1k1/2pb1q1p/p2b2p1/Qp1P1p2/4n3/P3BN1P/1PB2PP1/3RR1K1 w - - 0 1 > >Analysis by Deep Fritz: > >21.Bxe4! > ² (0.47) Depth: 1/3 00:00:00 >21.Bxe4 fxe4 22.Ng5 > ² (0.44) Depth: 2/6 00:00:00 >21.b4! > ² (0.47) Depth: 2/8 00:00:00 >21.b4! Qf6 > ² (0.53) Depth: 2/8 00:00:00 >21.b4 Nc3 22.Ng5 > ² (0.44) Depth: 3/10 00:00:00 >21.b3! > ² (0.47) Depth: 3/12 00:00:00 1kN >21.b3 f4 22.Bxe4 Rxe4 23.Ng5 > ² (0.38) Depth: 4/15 00:00:00 2kN >21.b4! > ² (0.41) Depth: 4/15 00:00:00 3kN >21.Bxe4! > ² (0.44) Depth: 4/15 00:00:00 3kN >21.Bxe4! fxe4 22.Ng5 Qf6 > ² (0.50) Depth: 4/15 00:00:00 3kN >21.Bxe4 fxe4 22.Ng5 Qf5 23.Rd4 h6 > ² (0.44) Depth: 5/14 00:00:00 8kN >21.b3! > ² (0.47) Depth: 5/21 00:00:00 14kN >21.b3 Qf6 22.Bxe4 fxe4 23.Nd4 Qe5 24.Nc6 Qh2+ 25.Kf1 > ² (0.47) Depth: 6/24 00:00:00 31kN >21.b3 Qf6 22.b4 Rad8 23.Bxe4 Rxe4 24.Bd4 Qf7 > ² (0.47) Depth: 7/23 00:00:00 115kN >21.b3 Nf6 22.Rd4 Kg7 23.Ng5 Qg8 24.Red1 h6 > ² (0.34) Depth: 8/25 00:00:00 333kN >21.Re2! > ² (0.38) Depth: 8/25 00:00:01 528kN >21.Re2 Nf6 22.Ng5 Qe7 23.g3 f4 24.gxf4 Bxf4 25.Rde1 Be5 > ² (0.31) Depth: 9/29 00:00:02 1577kN >21.Bb1! > ² (0.34) Depth: 9/29 00:00:04 2348kN >21.Bb1 Bc8 22.Bxe4 fxe4 23.Ng5 Qf6 24.Rd4 Qe5 25.Rxe4 Qh2+ 26.Kf1 Rxe4 > ² (0.28) Depth: 10/29 00:00:08 4721kN >21.b3! > ² (0.31) Depth: 10/29 00:00:10 6301kN >21.b4! > ² (0.34) Depth: 10/29 00:00:14 8313kN >21.b4 Bc8 22.Bd3 Bb7 23.Bxe4 fxe4 24.Ng5 Qf5 25.Ne6 Rec8 26.Nd4 Qxd5 > = (0.25) Depth: 11/31 00:00:22 13182kN >21.b4 Bc8 22.Bd3 Bd7 23.Bxe4 fxe4 24.Ng5 Qf6 25.Rd4 Qe5 26.f4 Qf5 > = (0.16) Depth: 12/31 00:00:41 24964kN >21.Bb1! > = (0.19) Depth: 12/31 00:00:58 35516kN >21.Rd4! > = (0.22) Depth: 12/34 00:01:40 62541kN >21.Rd4 Bc5 22.Rd3 Bd6 23.Bd4 Bc8 24.Rde3 Bb7 25.Bxe4 fxe4 26.Rxe4 Rxe4 > = (0.22) Depth: 13/35 00:03:18 124595kN >21.Rd4 Bc5 22.Rd3 Bd6 23.Bd4 Bc8 24.Nd2 Nf6 25.Rxe8+ Nxe8 26.Nf3 Bb7 > = (0.19) Depth: 14/35 00:05:00 190098kN >21.b4! > = (0.22) Depth: 14/38 00:06:33 248720kN >21.b4 Rad8 22.Rd3 Bc8 23.Bb3 g5 24.Nd4 f4 25.Bc1 Qg6 26.Bc2 > = (0.13) Depth: 15/41 00:15:23 586010kN >21.Rd4! > = (0.16) Depth: 15/41 00:18:07 695940kN > >(Blass, Tel-Aviv 20.05.2001) > > > >This analysis suggests that with 8 processors Deep Fritz may avoid b4 at >tournament time control. > >Uri and after more time Deep Fritz prefers b3 21.b3! = (0.19) Depth: 15/41 00:40:11 1535989kN Uri
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