Author: Robert Hyatt
Date: 22:47:23 02/15/03
Go up one level in this thread
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
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