Author: Mike Byrne
Date: 17:55:40 08/03/02
Go up one level in this thread
On August 02, 2002 at 17:08:03, Robert Hyatt wrote:
>On August 01, 2002 at 19:40:17, Martin Bauer wrote:
>
>>On August 01, 2002 at 08:12:13, Ulrich Tuerke wrote:
>>
>>>In order to get exact values, you in principle have to switch off alpa-beta at
>>>ply 1. But that's too expensive in terms of search tree sizes.
>>
>>Ok, thank you and all other people, who replyed to my question. I see it is not
>>so easy, I have to spend some extra work and be careful, that it does not waste
>>too much time.
>>
>>I dont want to trust the values at depth 1, because that is not a good look
>>ahead.
>>
>>>I do a pure minmax search at iteration #1. So, I get exact values at this level.
>>>These values - combined with other criteria - are some measure whether the best
>>>move is "an easy one".
>>
>>What about this Situation: I can recapture the queen in 1, but there also is a 7
>>move combination that wins two rooks. So a 1 ply search would say "easy move"
>>because it only sees the recapture of the queen. But in truth there is a
>>slightly better move that wins 2 rooks, what gives a little bit better value in
>>my program and I think in most others, too.
>>
>>if I half the search time in a 1min bullet game, I may be blind for the better 7
>>move combination, because of the reduced time. That is the reason, why I want to
>>ask for the difference of the two best moves with values resulting from depth 7.
>>Can ply 1 + some extra things replace ply 7. Or do I worry about things that
>>doesn't matter in practice? On what depends searching more or less in top
>>Engines?
>>
>>Bye
>>
>>Martin
>\
>Here is what I do in Crafty:
>
>1. I order all the root moves. To do this, I make each root move and do a
>captures-only q-search after each move to get a rough idea of the material
>situation on the board.
>
>2. If one move is better than all the rest (by at least 2.0 pawns) then I
>set the "easy move" flag.
>
>3. I then start the normal search.
>
>4. If, during the search, this move "fails low" at any point, "easy move" is
>cleared. If, during the search, another move becomes best, "easy move" is
>also cleared.
>
>5. When I have used 1/3 of the target time, and easy move is still set, I
>stop the search early.
>
>I do have some additional restrictions... IE this must be a recapture, ie
>To(move) must be identical to To(opponent's last move) which would make it
>a recapture. You don't want to say easy move too quickly. There is a
>famous position from Cray Blitz vs Belle in 1981, where white could play
>Qxb6 (the knight appeared to be hanging, but taking it led to great
>difficulty). Cray Blitz thought it was "easy" and didn't search long enough
>to see it was poisoned...
noise=1
Crafty v17.15 SE (2 cpus)
White(1): noise 1
noise level set to 1.
White(1): [D] 5r1k/6p1/1n2Q2p/4p3/8/7P/PP4PK/R1B1q3 w - - 28 bm Bxh6
White(1):
White(1): go
clearing hash tables
time surplus 0.00 time limit 10:00 (10:00)
nss depth time score variation (1)
starting thread 1
1 0.00 5.21 1. Qxb6 Rf2
1-> 0.03 5.21 1. Qxb6 Rf2
2 0.03 -- 1. Qxb6
2 0.03 ++ 1. Qxb6!!
2 0.03 5.67 1. Qxb6 Rc8 2. Qe3
2-> 0.03 5.67 1. Qxb6 Rc8 2. Qe3
3 0.03 -- 1. Qxb6
3 0.03 5.59 1. Qxb6 Qf2 2. Be3 Qf5
3-> 0.03 5.59 1. Qxb6 Qf2 2. Be3 Qf5
4 0.03 ++ 1. Qxb6!!
4 0.05 6.00 1. Qxb6 Qf2 2. Qe3 Qxe3 3. Bxe3
4-> 0.05 6.00 1. Qxb6 Qf2 2. Qe3 Qxe3 3. Bxe3
5 0.06 -- 1. Qxb6
5 0.06 5.72 1. Qxb6 Rc8 2. Qe3 Qxe3 3. Bxe3 Rc2
<HT>
5-> 0.08 5.72 1. Qxb6 Rc8 2. Qe3 Qxe3 3. Bxe3 Rc2
<HT>
6 0.09 ++ 1. Qxb6!!
6-> 0.11 6.11 1. Qxb6 Rc8 2. Qe3 Qxe3 3. Bxe3 Rc2
4. Bc1 <HT>
7 0.11 -- 1. Qxb6
7 0.30 -1.30 1. Qxb6 Rf1 2. Qd8+ Kh7 3. Qd3+ e4
4. Qxf1 Qxf1 5. b3 e3 6. Bb2 e2 7.
Bc3
7 0.33 ++ 1. Bxh6!!
7 0.41 -0.60 1. Bxh6 Qxa1 2. Qg6 Rg8 3. Be3 Rc8
4. Bxb6 Qxb2
(4) 7-> 0.80 -0.60 1. Bxh6 Qxa1 2. Qg6 Rg8 3. Be3 Rc8
4. Bxb6 Qxb2
(3) 8 0.87 -0.49 1. Bxh6 Qxa1 2. Qg6 Rg8 3. Qxb6 Qxa2
4. b4 Rc8 5. Bg5
(4) 8-> 1.36 -0.49 1. Bxh6 Qxa1 2. Qg6 Rg8 3. Qxb6 Qxa2
4. b4 Rc8 5. Bg5
9 1.48 ++ 1. Bxh6!!
(3) 9 1.64 0.00 1. Bxh6 Qxa1 2. Qg6 gxh6 3. Qxh6+ Kg8
4. Qg6+ Kh8 5. Qh6+
(4) 9-> 2.58 0.00 1. Bxh6 Qxa1 2. Qg6 gxh6 3. Qxh6+ Kg8
4. Qg6+ Kh8 5. Qh6+
(3) 10 2.98 0.00 1. Bxh6 Qxa1 2. Qg6 gxh6 3. Qxh6+ Kg8
4. Qg6+ Kh8 5. Qh6+
(2) 10-> 4.05 0.00 1. Bxh6 Qxa1 2. Qg6 gxh6 3. Qxh6+ Kg8
4. Qg6+ Kh8 5. Qh6+
11 4.75 0.00 1. Bxh6 Qxa1 2. Qg6 gxh6 3. Qxh6+ Kg8
4. Qg6+ Kh8 5. Qh6+
(2) 11-> 6.75 0.00 1. Bxh6 Qxa1 2. Qg6 gxh6 3. Qxh6+ Kg8
4. Qg6+ Kh8 5. Qh6+
12 11.41 0.07 1. Bxh6 Qxa1 2. Qe7 Rg8 3. Be3 Rc8
4. Bxb6 Qxb2 5. Bc7 Qb7 6. Qh4+ Kg8
7. Bxe5 Rc2 8. Qd8+ Kf7
(2) 12-> 16.33 0.07 1. Bxh6 Qxa1 2. Qe7 Rg8 3. Be3 Rc8
4. Bxb6 Qxb2 5. Bc7 Qb7 6. Qh4+ Kg8
7. Bxe5 Rc2 8. Qd8+ Kf7
13 21.27 0.10 1. Bxh6 Qxa1 2. Qe7 Rg8 3. Be3 Rc8
4. Bxb6 Qxb2 5. Bc7 Qxa2 6. Bxe5 Qg8
7. Qh4+ Qh7 8. Qxh7+ Kxh7 9. Kg3
13-> 27.98 0.10 1. Bxh6 Qxa1 2. Qe7 Rg8 3. Be3 Rc8
4. Bxb6 Qxb2 5. Bc7 Qxa2 6. Bxe5 Qg8
7. Qh4+ Qh7 8. Qxh7+ Kxh7 9. Kg3
White(1): ?
time=36.95 cpu=241% mat=1 n=47660K fh=92% nps=1289K
ext-> checks=4002140 recaps=128977 pawns=1500
ext-> 1rep=244593 thrt:34710 pawn sac=0
predicted=0 nodes=47660917 evals=0
endgame tablebase-> probes done=0 successful=0
SMP-> split=960 stop=211 data=10/64 cpu=1:29 elap=36.95
White(1): Bxh6
time used: 36.95
======================================================================
Black(1): undo
Qxb6 forced
White(1): Qxb6
time used: 19.07
clearing hash tables
time surplus 0.00 time limit 10:00 (10:00)
nss depth time score variation (1)
1 0.00 -5.37 1. ... Rf2 2. Qg6
1 0.00 ++ 1. ... Rc8!!
1-> 0.02 -4.98 1. ... Rc8
2 0.02 -- 1. ... Rc8
2 0.02 -5.60 1. ... Rc8 2. Qe3 Qf1
2 0.02 ++ 1. ... Rf2!!
2 0.02 -5.06 1. ... Rf2 2. Qg6 Qe2
2-> 0.02 -5.06 1. ... Rf2 2. Qg6 Qe2
3 0.02 -- 1. ... Rf2
3 0.02 -5.49 1. ... Rf2 2. a4 Kh7 3. b4
3-> 0.03 -5.49 1. ... Rf2 2. a4 Kh7 3. b4
4 0.03 -- 1. ... Rf2
4 0.03 -5.81 1. ... Rf2 2. Be3 Qxa1 3. Qb8+ Kh7
4. Bxf2
4 0.03 -5.72 1. ... Rc8 2. Qe3 Qxe3 3. Bxe3 Rc2
(2) 4-> 0.06 -5.72 1. ... Rc8 2. Qe3 Qxe3 3. Bxe3 Rc2
5 0.06 -- 1. ... Rc8
5 0.06 -6.04 1. ... Rc8 2. Qe3 Qxe3 3. Bxe3 Kh7
4. Kg3
5 0.10 ++ 1. ... Rf1!!
5 0.11 0.41 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. a4
5-> 0.11 0.41 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. a4
6 0.13 0.41 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. a4
6-> 0.14 0.41 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. a4
7 0.14 ++ 1. ... Rf1!!
7-> 0.16 0.80 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. a4
8 0.17 ++ 1. ... Rf1!!
(2) 8-> 0.21 1.19 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. a4
9 0.21 -- 1. ... Rf1
9 1.08 ++ 1. ... Rf1!!
9 1.81 3.52 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. a4 e3 6. b4 e2 7. Bb2
Qxa1 8. Bxa1 e1=Q
9-> 1.83 3.52 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. a4 e3 6. b4 e2 7. Bb2
Qxa1 8. Bxa1 e1=Q
10 2.02 3.57 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. Bb2 e2 7. b5
Qxa1 8. Bxa1 e1=Q
10-> 2.06 3.57 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. Bb2 e2 7. b5
Qxa1 8. Bxa1 e1=Q
11 2.44 3.29 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. Bb2 e2 7. b5
Qf4+ 8. Kh1 Qd2 9. Bxg7 Kxg7
11-> 2.56 3.29 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. Bb2 e2 7. b5
Qf4+ 8. Kh1 Qd2 9. Bxg7 Kxg7
12 2.85 ++ 1. ... Rf1!!
12 17.24 4.04 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. Bb2 e2 7. a3
Qf4+ 8. Kh1 Qd2 9. Bd4 Qxd4 10. Re1
12-> 17.50 4.04 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. b4 e3 6. Bb2 e2 7. a3
Qf4+ 8. Kh1 Qd2 9. Bd4 Qxd4 10. Re1
13 19.74 3.98 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. a3 e3 6. Bxe3 Qxa1 7.
Bd4 Qc1 8. Bc3 Qf4+ 9. Kh1 Kg6 10.
b4
13-> 20.19 3.98 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. a3 e3 6. Bxe3 Qxa1 7.
Bd4 Qc1 8. Bc3 Qf4+ 9. Kh1 Kg6 10.
b4
14 24.89 3.78 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. a3 e3 6. Bxe3 Qxa1 7.
Bd4 Qc1 8. Be5 Qe3 9. Bg3 Kg6 10. a4
14-> 25.53 3.78 1. ... Rf1 2. Qd8+ Kh7 3. Qd3+ e4 4.
Qxf1 Qxf1 5. a3 e3 6. Bxe3 Qxa1 7.
Bd4 Qc1 8. Be5 Qe3 9. Bg3 Kg6 10. a4
Black(0): ?
time=34.41 cpu=199% mat=-4 n=46304K fh=96% nps=1345K
ext-> checks=4706810 recaps=135233 pawns=14978
ext-> 1rep=369980 thrt:54945 pawn sac=0
predicted=0 nodes=46304432 evals=0
endgame tablebase-> probes done=0 successful=0
SMP-> split=1304 stop=129 data=10/64 cpu=1:08 elap=34.41
Black(1): Rf1
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