Author: Robert Hyatt
Date: 08:41:51 04/20/04
Go up one level in this thread
On April 20, 2004 at 06:10:05, Omid David Tabibi wrote:
>On April 19, 2004 at 22:50:56, Robert Hyatt wrote:
>
>>On April 19, 2004 at 15:49:14, Andrew Williams wrote:
>>
>>>On April 18, 2004 at 19:56:25, Andrew Wagner wrote:
>>>
>>>Try searching longer. PM is getting this at ply 27 (78kns, 0.76 seconds) at the
>>>moment, although I've seen it return the correct move at various different plies
>>>over the years.
>>>
>>>Andrew
>>
>>Something might be wrong. It is a 26 ply combination to win a pawn, with no
>>hash table at all... Hashing usually lets us hit the solution quicker. IE
>>Crafty typically solves it at depth=18...
>
>In his article "PEASANT: An endgame program for kings and pawns", Newborn
>writes: "Position 70 would require a 30-ply search (25,000 hours)"
I remember Monty's paper, but that was not where I got the 26 from. Somewhere
in the past 15 years someone posted some detailed analysis on this position and
had reported that white wins a pawn on the 27th ply, concluding that a 26 ply
search (+captures) would be enough to see it. The first program to solve it was
chess 4.7 at depth=23, taking 23 minutes on the CDC Cyber 176. I've never seen
a 26 ply search that didn't find this, although if Monty was correct with 30
plies, that would not be unreasonable.
Intuitively 30 is too big, because Crafty and Cray Blitz have almost always
solved this at depth=18, and that puts quite a demand on the hash table...
>
>But running the position on Falcon:
>
>Falcon 1.0.12.6 running on GenuineIntel 733MHz 256MB:
>depth time nodes nps score variation
>18/18 0.12 17k 149k 0.76 1.a1b2 a7a6 2.b2c3 a6b7 3.c3d3 b7c7
> 4.d3e3 c7d7 5.e3d2 d7c7 6.d2d3 c7b6
> 7.d3c2 b6b7 8.c2c3 b7c7 9.c3c4 c7d7
>19/20 1.05 284k 270k 0.76 1.a1b2 a7a8 2.b2c3 a8b7 3.c3d3
>19/20 1.05 284k 270k 0.86 1.a1b1++
>19/20 1.06 284k 268k 1.92 1.a1b1++
>19/20 2.58 744k 288k 2.36 1.a1b1 a7b7 2.b1c1 b7c7 3.c1d1 c7d7
> 4.d1c2 d7c8 5.c2d2 c8d7 6.d2c3 d7e7
> 7.c3c4 e7d7 8.c4b5 d7c7 9.b5a5 c7b7
> 10.a5b4
>
>It takes a mere 1 second at depth 19!
I just tried this again, and as expected, things have changed. With default
hash, it takes crafty to depth=23 to solve it, in .1 seconds, this on my 750mhz
laptop.
So perhaps the 26 is not that far off for Andrew...
22-> 0.10 1.21 1. Kb2 Ka8 2. Kc2 Kb8 3. Kc3 Kb7 4.
Kc4 Kb6 5. Kb3 Kc7 6. Kc2 Kc8 7. Kd2
<HT>
23 0.11 1.21 1. Kb2 Ka8 2. Kc2 Kb8 3. Kc3 Kb7 4.
Kc4 Kb6 5. Kb3 Kc7 6. Kc2 Kc8 7. Kd2
<HT>
23 0.11 +1 1. Kb1!!
23 0.11 1.21 1. Kb1 Ka8 2. Kb2 Kb7 3. Kc3 Kc7 4.
Kd3 Kb7 5. Kc4 Kb6 6. Kb3 Kc7 7. Kc2
Kc8 8. Kd2 <HT>
23-> 0.11 1.21 1. Kb1 Ka8 2. Kb2 Kb7 3. Kc3 Kc7 4.
Kd3 Kb7 5. Kc4 Kb6 6. Kb3 Kc7 7. Kc2
Kc8 8. Kd2 <HT>
24 0.12 +1 1. Kb1!!
24 0.12 +3 1. Kb1!!
24 0.15 3.54 1. Kb1 Kb7 2. Kc1 Kb8 3. Kc2 Kc8 4.
Kd2 Kc7 5. Kd3 Kb7 6. Ke3 Kc7 7. Kf3
Kd7 8. Kg3 Ke7 9. Kh4 Kf6 10. Kh5 Kf7
11. Kg5 Kg7 12. Kxf5 Kf7
24-> 0.17 3.54 1. Kb1 Kb7 2. Kc1 Kb8 3. Kc2 Kc8 4.
Kd2 Kc7 5. Kd3 Kb7 6. Ke3 Kc7 7. Kf3
Kd7 8. Kg3 Ke7 9. Kh4 Kf6 10. Kh5 Kf7
11. Kg5 Kg7 12. Kxf5 Kf7
>
>
>
>>
>>
>>>
>>>> Ok, I've been banging my head against this one all day. This is Fine #70:
>>>>[d]8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - -
>>>>
>>>> Below is Trueno's output for the position. Of course, the correct result is
>>>>+1.8 (Trueno counts pawns as .9) with the best move of Kb1. It finds that but
>>>>then changes its mind. I've been told that this position is generally infamous
>>>>for catching hash bugs. Anyone have any suggestions how to attack this one? Null
>>>>move is off, and I'm evaluating material only, using a single replace-always
>>>>hash table. Any suggestions would be VERY much appreciated). Andrew
>>>>
>>>> -------------------------------
>>>> 8 | . | . | . | . | . | . | . | . |
>>>> |-------------------------------|
>>>> 7 | k | . | . | . | . | . | . | . |
>>>> |-------------------------------|
>>>> 6 | . | . | . | p | . | . | . | . |
>>>> |-------------------------------|
>>>> 5 | p | . | . | P | . | p | . | . |
>>>> |-------------------------------|
>>>> 4 | P | . | . | P | . | P | . | . |
>>>> |-------------------------------|
>>>> 3 | . | . | . | . | . | . | . | . |
>>>> |-------------------------------|
>>>> 2 | . | . | . | . | . | . | . | . |
>>>> |-------------------------------|
>>>> 1 | K | . | . | . | . | . | . | . |
>>>> -------------------------------
>>>> A B C D E F G H
>>>>
>>>>Fifty: 0 En Passant: 0
>>>>Castle: 0000
>>>>Ply: 0 To move: True
>>>>
>>>>
>>>>1. Score: .9; Time: 0; nodes: 4; PV: a1-b2
>>>>2. Score: .9; Time: 0; nodes: 15; PV: a1-b2 a7-b6
>>>>3. Score: .9; Time: 0; nodes: 48; PV: a1-b2 a7-b6 b2-c3
>>>>4. Score: .9; Time: 0; nodes: 111; PV: a1-b2 a7-b6 b2-c3 b6-c7
>>>>5. Score: .9; Time: 0; nodes: 231; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4
>>>>6. Score: .9; Time: 0; nodes: 408; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>7. Score: .9; Time: 0; nodes: 671; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7 c4-d3
>>>>8. Score: .9; Time: 0; nodes: 1003; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7
>>>>9. Score: .9; Time: 0; nodes: 1443; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4
>>>>10. Score: .9; Time: 0; nodes: 1968; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7
>>>>11. Score: .9; Time: 0; nodes: 2735; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3
>>>>12. Score: .9; Time: 0; nodes: 3522; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7
>>>>13. Score: .9; Time: 0; nodes: 4416; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4
>>>>14. Score: .9; Time: 1; nodes: 5410; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7
>>>>15. Score: .9; Time: 1; nodes: 6584; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3
>>>>16. Score: .9; Time: 1; nodes: 7885; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7
>>>>17. Score: .9; Time: 1; nodes: 9273; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4
>>>>18. Score: .9; Time: 1; nodes: 10845; PV: a1-b2 a7-b6 b2-c3 b6-c7 c3-c4 c7-d7
>>>>c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7
>>>>19. Score: .9; Time: 1; nodes: 16249; PV: a1-b2 a7-b6 b2-c3 b6-b7 c3-c4 b7-b6
>>>>c4-d3 b6-c7 d3-c4 c7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3
>>>>20. Score: .9; Time: 1; nodes: 18816; PV: a1-b2 a7-b6 b2-c3 b6-b7 c3-c4 b7-b6
>>>>c4-d3 b6-c7 d3-c4 c7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3 d7-e7 d3-c4 e7-d7 c4-d3
>>>>d7-e7
>>>>21. Score: 1.8; Time: 2; nodes: 30305; PV: a1-b1 a7-b6 b1-c2 b6-b7 c2-d2 b7-c7
>>>>d2-d3 c7-b6 d3-e3 b6-c7 e3-f3 c7-d7 f3-g3 d7-e7 g3-h4 e7-f6 h4-h5 f6-f7 h5-g5
>>>>f7-e8 g5-f5
>>>>22. Score: 1.8; Time: 2; nodes: 40127; PV: a1-b1 a7-b6 b1-c2 b6-b7 c2-d2 b7-c7
>>>>d2-d3 c7-b6 d3-e3 b6-c7 e3-f3 c7-d7 f3-g3 d7-e7 g3-h4 e7-f6 h4-h5 f6-f7 h5-g5
>>>>f7-e8 g5-f5 e8-e7
>>>>23. Score: 1.8; Time: 2; nodes: 50869; PV: a1-b1 a7-b6 b1-c2 b6-b7 c2-d2 b7-c7
>>>>d2-d3 c7-b6 d3-e3 b6-c7 e3-f3 c7-d7 f3-g3 d7-e7 g3-h4 e7-f6 h4-h5 f6-f7 h5-g5
>>>>f7-e8 g5-f5 e8-e7 f5-e4
>>>>24. Score: 1.8; Time: 3; nodes: 64039; PV: a1-a2 a7-b6 a2-b3 b6-c7 b3-c3 c7-b6
>>>>c3-c2 b6-a6 c2-d2 a6-b6 d2-e3 b6-c7 e3-f3 c7-d7 f3-g3 d7-e7 g3-h4 e7-f6 h4-h5
>>>>f6-f7 h5-g5 f7-e8 g5-f5 e8-e7
>>>>25. Score: 1.8; Time: 3; nodes: 75500; PV: a1-b2 a7-b6 b2-c3 b6-b7 c3-d2 b7-c7
>>>>d2-d3 c7-b6 d3-e3 b6-c7 e3-f3 c7-d7 f3-g3 d7-e7 g3-h4 e7-f6 h4-h5 f6-f7 h5-g5
>>>>f7-e8 g5-f5 e8-e7 f5-e4 e7-d7 e4-f5
>>>>26. Score: 1.8; Time: 4; nodes: 83644; PV: a1-b2 a7-b6 b2-c3 b6-b7 c3-d2 b7-c7
>>>>d2-d3 c7-b6 d3-e3 b6-c7 e3-f3 c7-d7 f3-g3 d7-e7 g3-h4 e7-f6 h4-h5 f6-f7 h5-g5
>>>>f7-e8 g5-f5 e8-e7 f5-e4 e7-d7 e4-f5 d7-e7
>>>>I play a1-b2
>>>>Nodes: 83k; NPS: 21414; QNodes: 0; MO%: 98; FHA: 2; HC%: 55; Hash%: 58; NM%: 0;
>>>>egtb hits: 0; Ext's: 0; Total time searched: 3.906
>>>>
>>>>(MO% = first-move fail-high percent; FHA isn't important; HC is the percent of
>>>>time the hash move causes a cutoff; Hash% is the percent of time I find the move
>>>>in the hash table; the rest is un-important)
>>>>
>>>>(told you it was a long post)
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