Author: Anthony Cozzie
Date: 23:26:02 02/15/03
Go up one level in this thread
On February 16, 2003 at 01:47:23, Robert Hyatt 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. 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. >> >>There has to be some way to fix this, but I can't seem to find it. >> >>anthony > > >How can it be useful from the hash? IE iteration N-1 should not have >enough "draft" to be useful in iteration N. > >Crafty says draw at depth=9 on my laptop: > > 7 0.72 -1.44 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. c5 Qf3 > 7-> 0.94 -1.44 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. c5 Qf3 > 8 1.72 -1.29 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. Qa6 Nf3+ > 7. Ke2 Ng1+ 8. Ke1 > 8-> 2.13 -1.29 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. Qa6 Nf3+ > 7. Ke2 Ng1+ 8. Ke1 > 9 3.03 -- 1. ... Qh5+ > 9 4.63 0.00 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. Rb8 Nf3+ > 7. Ke2 Ng1+ 8. Ke1 > 9-> 5.88 0.00 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. Rb8 Nf3+ > 7. Ke2 Ng1+ 8. Ke1 > 10 8.27 0.00 1. ... Qh5+ 2. Kf1 Qh3+ 3. Ke1 Nf3+ > 4. Ke2 Ng1+ 5. Ke1 Rc8 6. Rb8 Nf3+ > 7. Ke2 Ng1+ 8. Ke1 well, at depth N, after Qh5 Kf1 Qh1 Ke2, 2 moves are checks and are extended, but the 'depth remaining' is N-2 < N-1. I'm sure the position is a draw, but the fact tha Zappa is unable to recognize this worries me. anthony
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