Author: Filip Tvrzsky
Date: 05:06:01 02/16/03
Go up one level in this thread
On February 16, 2003 at 03:27:41, Uri Blass wrote: >On February 16, 2003 at 01:02:17, Anthony Cozzie wrote: > >>[D]3r2k1/pR3ppp/3Qp3/4n3/2P1PP2/4B3/4KP2/7q b - - 0 30 >> >>Zappa gives: >> >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 4 00:00:00.03 2kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 5 00:00:00.08 6kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 6 00:00:00.26 20kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 7 00:00:00.63 54kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 8 00:00:01.34 131kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 9 00:00:02.49 295kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 10 00:00:04.92 688kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qh5 >> = (9.21) Depth: 11 00:00:09.54 1542kN >> >>which is clearly silly. >> >>Without the transposition table, I get the following, rather messy, output: >> >>1...Rb8 >> - (9.63) Depth: 8 00:00:10.94 1532kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qd1 4. Qxd1 Rxd1 >> - (8.13) Depth: 8 00:00:17.33 2434kN >>1...Qf3 2. Kf1 Qh1 3. Ke2 Qh5 4. Kf1 Nc6 5. Rd7 Qh1 6. Ke2 Rxd7 7. Qxd7 Qxe4 >> = (3.56) Depth: 8 00:00:20.96 3011kN >>1...Qf3 2. Ke1 Qh1 3. Ke2 Qh5 4. Kf1 Qh3 5. Ke2 Qg4 6. Kf1 Qxf4 >> - (3.06) Depth: 9 00:00:35.07 5489kN >>1...Qf3 2. Ke1 Qh1 3. Ke2 Qh5 4. Kf1 Qh3 5. Ke2 Qg4 6. Kf1 Qh4 7. Qxd8 Qxd8 8. >>fxe5 Qd3 9. Kg2 >> = (2.61) Depth: 9 00:00:50.34 8168kN >>1...Qh5 2. Kf1 Qh1 3. Ke2 Qf3 4. Ke1 Nc6 5. Rd7 Qh1 6. Kd2 Qh5 >> - (2.11) Depth: 10 00:01:31.06 15360kN >>1...Qf3 2. Ke1 Qh1 3. Ke2 Qh5 4. Kf1 Qh3 5. Ke1 Nc6 6. Rd7 Qh1 7. Ke2 Rc8 8. f3 >>a5 >> = (2.40) Depth: 10 00:02:22.18 24297kN >>1...Qf3 2. Ke1 Qh1 3. Ke2 Qh5 4. Kf1 Nc6 5. Rd7 Qh1 6. Ke2 Rc8 7. f3 a5 8. Bc5 >>Qc1 >> = (2.20) Depth: 11 00:04:18.74 43985kN >> >>At depth 8, it starts to realize it is running out of checks, but even at depth >>11 it doesn't really understand the position. >> >>The problem appears to be as follows: >> >>Zappa analyzes the position at depth 1, and determines it can win white's queen >>with Rxd6. Search is stopped. >> >>Zappa analyzes the position at depth N, and follows the tree Qh5 Kf1 Qh1 Ke2. >>Here Zappa does not declare a repetition because the position has occurred only >>1 time in the tree. > >This is a mistake. > >If you see repetition of the root position You should evaluate it as a draw. > >I evaluate every repetition as a draw. >I can understand not evaluating every repetition as a draw but the only >repetition that it make sense not to evaluate as a draw are repetition of >history positions that mean repetition of positions that were at least 1 ply >before the root. > >If you are winning then you can win without repetition of the root position so >it does not make sense not to evaluate repetition of the root position as a >draw. > >Note that there are disadvantages of not evaluating repetition of history >positions as a draw and in positions that the program does not understand it may >waste time instead of playing a better move that is going to reduce it's score >but improve it's position. > >It is not clear to me that evaluating repetition not as a draw is better so >I prefered the simple solution that is used by many commercial programs and it >is to evaluate every repetition as a draw. > >I think that the best solution is to evaluate repetition of history position as >some average between a draw and the score that the program remember but I did >not try it and I did not consider it as important enough to test it. > > However, this is the root position, and its value has been >>stored in the hash as 9.21 by iteration N-1. And the cycle continues. > >The first thing that you need to check is if there is a repetition and only if >you see no repetition you can use the score from the hash tables. > >Uri I agree with Uri and want to add that IMHO there is no point in storing the root position evalution in the hash table during the search. I believe that repetition is one of few things which my engine handles quite well: Flip WB2: D5 00:00 8,04 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qf3 4.Ke1 D5 00:00 8,02 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qg4 4.Kf1 Rxd6 5.fxe5 Rd2 D5 00:00 7,93 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qh1 4.fxe5 D5 00:00 7,75 1. ... Qh5 2.Kf1 Qh3 3.Ke2 g5 4.fxe5 D5 00:00 7,34 1. ... Qh5 2.Kf1 Nc6 3.Qxd8 D5 00:00 6,60 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Rc8 4.Rb8 D5 00:00 5,58 1. ... Qh5 2.Kf1 Nc6 3.Rb8 Qh1 4.Ke2 Qh5 5.Kd3 Qd1 6.Bd2 Nb4 7.Kc3 D5 00:00 3,85 1. ... Qh5 2.Kf1 Nc6 3.Rd7 Qh1 4.Ke2 Rxd7 5.Qxd7 Qxe4 D6 00:00 3,85 1. ... Qh5 2.Kf1 Nc6 3.Rd7 Qh1 4.Ke2 Rxd7 D6 00:00 3,84 1. ... Qh5 2.Kf1 Rb8 3.fxe5 D6 00:00 3,84 1. ... Qh5 2.Kf1 Nc6 3.Rd7 Qh1 4.Ke2 Rxd7 5.Qxd7 Qxe4 D7 00:00 3,84 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qf3 4.Ke1 D7 00:00 3,83 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qf3 4.Ke1 Rf8 D7 00:00 3,77 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qg4 4.Kf1 Qxf4 D7 00:00 3,61 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Nf3 4.Ke2 Nd4 5.Qxd4 Qh5 6.Kd2 Qa5 7.Kc2 Rxd4 8.Bxd4 Qa2 9.Kc1 D7 00:00 3,21 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Nc6 4.Rd7 Rb8 5.Qxc6 D7 00:00 2,54 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Nf3 4.Ke2 Nd4 5.Qxd4 h6 D7 00:01 1,81 1. ... Qh5 2.Kf1 Nc6 3.Rd7 Rc8 4.Qd3 Qh3 5.Kg1 a5 D7 00:01 1,82 1. ... Nc6 2.Rd7 Rc8 3.Bb6 D7 00:01 1,83 1. ... Nc6 2.Rd7 Rc8 3.f5 Qxe4 D7 00:01 1,89 1. ... Nc6 2.Rd7 Rc8 3.f5 Qxe4 4.fxe6 fxe6 5.Ke1 D7 00:01 1,95 1. ... Nc6 2.Rd7 Rc8 3.f3 a5 4.c5 a4 5.Bf2 D8 00:01 1,95 1. ... Nc6 2.Rd7 Rxd7 3.Qxd7 Qh5 4.Kd2 h6 D8 00:01 1,94 1. ... Nc6 2.Rd7 Rxd7 3.Qxd7 Qh5 4.f3 Kh8 D8 00:01 1,88 1. ... Nc6 2.Rd7 Rxd7 3.Qxd7 Nd4 4.Bxd4 Qxe4 5.Kd2 Kf8 6.Bxg7 Kxg7 7.Kc3 Qf3 8.Kb2 8.Ka1 D8 00:01 1,72 1. ... Nc6 2.Rd7 Rxd7 3.Qxd7 Nd4 4.Bxd4 Qxe4 5.Kd2 a5 6.Bxg7 Qxf4 7.Kc2 D8 00:01 1,32 1. ... Nc6 2.Rd7 Rxd7 3.Qxd7 Nd4 4.Bxd4 Qxe4 5.Kd1 Qd3 6.Kc1 Qxc4 7.Kb1 Qc2 8.Ka1 Qd1 9.Ka2 Qd2 10.Ka1 Qc1 11.Ka2 e5 D8 00:02 0,94 1. ... Nc6 2.Rd7 Qh5 3.Kf1 Rc8 4.Qxc6 Qh3 D8 00:02 0,96 1. ... Qh5 2.Ke1 Nf3 3.Ke2 Nd4 4.Kd2 Nc6 5.Rd7 Rc8 6.Rd8 Nxd8 D8 00:02 0,98 1. ... Qh5 2.Ke1 Nf3 3.Ke2 Nd4 4.Kd2 Nc6 5.f3 D8 00:02 1,04 1. ... Qh5 2.Ke1 Nf3 3.Ke2 Nd4 4.Kd2 Nc6 5.Bd4 D8 00:02 1,20 1. ... Qh5 2.Ke1 Nf3 3.Ke2 Nd4 4.Kd2 Nc6 5.Rd7 Rc8 6.f5 D8 00:02 1,45 1. ... Qh5 2.Kf1 Qh3 3.Ke2 Qg4 4.Kf1 Nc6 5.Rd7 Rc8 6.Qd1 Qxd1 7.Rxd1 a5 D9 00:04 1,45 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Nf3 4.Ke2 Ng1 5.Ke1 Qxe3 6.fxe3 Nf3 7.Ke2 D9 00:04 1,44 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Qg4 4.fxe5 D9 00:04 1,38 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Qg4 4.fxe5 Qg1 5.Ke2 Qg4 6.Kd3 Qd1 7.Bd2 Qf1 8.Kc2 Rc8 D9 00:04 1,22 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Nd7 D9 00:04 0,82 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Qxe3 4.fxe3 Nf3 5.Ke2 Rxd6 6.Kxf3 g5 D9 00:05 0,15 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Qxe3 4.fxe3 Nd3 5.Qxd3 h5 6.Rxa7 Rxd3 7.Ra8 Kh7 8.Ke2 Rc3 D9 00:05 0,00 1. ... Qh5 2.Kf1 Qh3 3.Ke1 Nf3 4.Ke2 Ng1 5.Ke1 Nf3 D10 00:08 0,00 1. ... Qh5 2.Kf1 Qh1 3.Ke2 D11 00:14 0,00 1. ... Qh5 2.Kf1 Qh1 3.Ke2 Filip
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