Author: Dann Corbit
Date: 15:56:19 04/17/02
Go up one level in this thread
On April 17, 2002 at 17:45:03, Peter McKenzie wrote:
>On April 17, 2002 at 16:53:30, Gian-Carlo Pascutto wrote:
>
>>On April 17, 2002 at 16:40:01, Dann Corbit wrote:
>>
>>>I don't see how it can completely remove the tactic from ever being seen unless
>>>the implementation of null move is broken.
>>
>>If it has a zugzwang, you will _never_ see it if you don't check for it
>>(verification search, double nullmove), or use another trick like force
>>nullmoves away from the root (that is what Crafty does).
>>
>>You can always play the 'nullmove' no matter what depth, so you'll
>>never realize the nullmove is no good.
>>
>>i.e. you make an illegal move that is not possible in the real game, and
>>increasing search depth won't change this.
>
>Yes, you are correct. Some programs can never solve the following:
>
>[D]8/8/2p5/pkp3R1/7B/P7/2p3K1/8 w - -
>
>http://homepages.caverock.net.nz/~peter/eg_test/pet013.htm
How do we know that they can never solve it? Maybe they just take a
stupendously long time. Here is a crafty session, where I let it reuse the hash
table on subsequent searches:
choose from book moves randomly (using weights.)
choose from 5 best moves.
book learning enabled
result learning enabled
position learning enabled
threshold set to 9 pawns.
5 piece tablebase files found
19045kb of RAM used for TB indices and decompression tables
Crafty v18.13
White(1): hash 200M
hash table memory = 192M bytes.
White(1): st 60
search time set to 60.00.
White(1): epdpfga \a4.epd a4.out
PFGA: EPD record: 1
end-game phase
clearing hash tables
time surplus 0.00 time limit 1:00 (1:00)
nss depth time score variation (1)
8-> 0.20 -0.61 1. Rxc5+ Kxc5 2. Bg5 Kd5 3. Bc1 c5
4. Kf3 c4 5. Ke3
9 0.39 -0.52 1. Rxc5+ Kxc5 2. Bg5 Kd4 3. Kf3 c5
4. Ke2 Kc3 5. Bc1 c4
9-> 0.61 -0.52 1. Rxc5+ Kxc5 2. Bg5 Kd4 3. Kf3 c5
4. Ke2 Kc3 5. Bc1 c4
10 0.71 -0.45 1. Rxc5+ Kxc5 2. Bg5 Kd4 3. Kf3 c5
4. Ke2 Kc3 5. Bc1 c4 6. a4
10-> 0.90 -0.45 1. Rxc5+ Kxc5 2. Bg5 Kd4 3. Kf3 c5
4. Ke2 Kc3 5. Bc1 c4 6. a4
11 1.27 -- 1. Rxc5+
11 1.39 -1.15 1. Rxc5+ Kxc5 2. Bg5 Kd4 3. Kf3 Kd3
4. Bc1 c5 5. Kf4 c4 6. Ke5 c3
11-> 2.26 -1.15 1. Rxc5+ Kxc5 2. Bg5 Kd4 3. Kf3 Kd3
4. Bc1 c5 5. Kf4 c4 6. Ke5 c3
12 2.27 ++ 1. Rxc5+!!
12 2.87 -0.68 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 c5
4. Bc1 Kb3 5. Ke4 c4 6. Kd4 c3 7. a4
12-> 3.64 -0.68 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 c5
4. Bc1 Kb3 5. Ke4 c4 6. Kd4 c3 7. a4
13 4.81 -0.78 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 c5 5. Kf4 c4 6. Ke5 c3 7. Kd5
a4 <HT>
13-> 7.01 -0.78 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 c5 5. Kf4 c4 6. Ke5 c3 7. Kd5
a4 <HT>
14 8.26 -0.75 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 c5 5. a4 c4 6. Kf4 c3 7. Ke5
Kc4 8. Kd6 <HT>
14-> 11.79 -0.75 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 c5 5. a4 c4 6. Kf4 c3 7. Ke5
Kc4 8. Kd6 <HT>
15 14.61 -- 1. Rxc5+
15 15.66 -1.17 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 c5 5. a4 c4 6. Bh6 Kc3 7. Bc1
Kb3 8. Ke4 Kxa4
15-> 25.29 -1.17 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 c5 5. a4 c4 6. Bh6 Kc3 7. Bc1
Kb3 8. Ke4 Kxa4
16 28.17 -0.85 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 a4 5. Be3 c5 6. Bc1 c4 7. Kf4
c3 8. Ke5 Kc4 9. Kd6
16-> 40.35 -0.85 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. Bc1 a4 5. Be3 c5 6. Bc1 c4 7. Kf4
c3 8. Ke5 Kc4 9. Kd6
17 43.54 -- 1. Rxc5+
17 46.47 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kd3
4. a4 c5 5. Bc1 c4 6. Be3 c3 7. Bc1
Kd4 8. Be3+ Kc4 9. Ke2 Kb3 10. Kd3
time=1:00 cpu=99% mat=5 n=17613837 fh=94% nps=290k
ext-> chk=677588 cap=617 pp=13086 1rep=9212 mate=746
predicted=0 nodes=17613837 evals=0
endgame tablebase-> probes done=10070 successful=10070
White(1): st 999
search time set to 999.00.
White(1): epdpfga \a4.epd a4.out
PFGA: EPD record: 1
time surplus 0.00 time limit 16:39 (16:39)
nss depth time score variation (1)
8 0.42 -5.37 1. Rg3 c1=Q 2. Rb3+ Ka4 3. Rf3 Qc2+
4. Kg3 Kb5 5. Bf6 Qe4
8 0.56 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
8-> 0.56 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
9 0.56 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
9-> 0.66 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
10 0.66 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
10-> 0.80 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
11 0.80 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
11-> 0.93 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
12 0.93 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
12-> 1.21 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
13 1.22 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
13-> 1.80 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
14 1.80 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
14-> 3.21 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
15 3.21 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
15-> 5.97 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
16 5.97 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
16-> 11.08 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
17 11.08 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
17-> 20.92 -1.23 1. Rxc5+ Kxc5 2. Bg5 Kc4 <HT>
18 28.33 -- 1. Rxc5+
18 1:05 -8.72 1. Rxc5+ Kxc5 2. Bg5 Kc4 3. Kf3 Kb3
4. Bc1 Ka2 5. a4 Kb1 6. Bf4 c1=Q 7.
Bc7 Qa3+ 8. Kf4 Qxa4+ 9. Ke3 Qb3+ 10.
Kd4 Qd1+ 11. Kc4 Qc2+ 12. Kd4 c5+ 13.
Kd5 a4
time=16:39 cpu=100% mat=5 n=482916432 fh=87% nps=483k
ext-> chk=43611667 cap=5777 pp=1816621 1rep=763949 mate=4893
predicted=0 nodes=482916432 evals=0
endgame tablebase-> probes done=44439 successful=44439
White(1): epdpfga \a4.epd a4.out
PFGA: EPD record: 1
time surplus 0.00 time limit 16:39 (16:39)
nss depth time score variation (1)
9 0.52 -1.62 1. a4+ Kb6 2. Rxc5 Kxc5 3. Bg5 Kb4
4. Kf3 Kxa4 5. Ke4 Kb3
9-> 0.64 -1.62 1. a4+ Kb6 2. Rxc5 Kxc5 3. Bg5 Kb4
4. Kf3 Kxa4 5. Ke4 Kb3
10 0.71 -- 1. a4+
10 2.19 -5.07 1. a4+ Kb6 2. Bf2 c1=Q 3. Rf5 Qc2 4.
Rg5 Qe4+ 5. Kg3 Qd3+ 6. Kg2 Qc2 <HT>
10-> 2.47 -5.07 1. a4+ Kb6 2. Bf2 c1=Q 3. Rf5 Qc2 4.
Rg5 Qe4+ 5. Kg3 Qd3+ 6. Kg2 Qc2 <HT>
11 4.93 -5.22 1. a4+ Kb6 2. Bf2 c1=Q 3. Rf5 Qc2 4.
Rg5 Ka6 5. Rxc5 Qxa4 6. Kf3 Kb6
11-> 5.68 -5.22 1. a4+ Kb6 2. Bf2 c1=Q 3. Rf5 Qc2 4.
Rg5 Ka6 5. Rxc5 Qxa4 6. Kf3 Kb6
12 8.60 -5.18 1. a4+ Kb6 2. Bf2 c1=Q 3. Rh5 Qc2 4.
Kg3 Qg6+ 5. Kh4 Qf6+ 6. Kg3 Qd6+ 7.
Kh3 Qd7+ 8. Kh4 Qd8+ 9. Kh3 Qc8+ 10.
Kg2
12-> 9.38 -5.18 1. a4+ Kb6 2. Bf2 c1=Q 3. Rh5 Qc2 4.
Kg3 Qg6+ 5. Kh4 Qf6+ 6. Kg3 Qd6+ 7.
Kh3 Qd7+ 8. Kh4 Qd8+ 9. Kh3 Qc8+ 10.
Kg2
13 13.20 -5.15 1. a4+ Kb6 2. Bf2 c1=Q 3. Rh5 Qc2 4.
Kg3 Qxa4 5. Bxc5+ Kb5 6. Bf2+ Ka6 7.
Bc5 <HT>
13-> 14.81 -5.15 1. a4+ Kb6 2. Bf2 c1=Q 3. Rh5 Qc2 4.
Kg3 Qxa4 5. Bxc5+ Kb5 6. Bf2+ Ka6 7.
Bc5 <HT>
14 31.50 -5.37 1. a4+ Kb6 2. Bf2 c1=Q 3. Rh5 Qc2 4.
Rg5 Ka6 5. Rxc5 Qxa4 6. Kf3 Qd1+ 7.
Ke4 Qd6 8. Re5 a4
14-> 39.95 -5.37 1. a4+ Kb6 2. Bf2 c1=Q 3. Rh5 Qc2 4.
Rg5 Ka6 5. Rxc5 Qxa4 6. Kf3 Qd1+ 7.
Ke4 Qd6 8. Re5 a4
15 1:09 ++ 1. a4+!!
15 10:16 -2.30 1. a4+ Kb6 2. Rxc5 Kxc5 3. Bg5 Kb4
4. Kf3 Kxa4 5. Ke4 Ka3 6. Bc1+ Ka2
7. Kd3 Kb1 8. Kd2 c5 9. Ba3
15-> 10:32 -2.30 1. a4+ Kb6 2. Rxc5 Kxc5 3. Bg5 Kb4
4. Kf3 Kxa4 5. Ke4 Ka3 6. Bc1+ Ka2
7. Kd3 Kb1 8. Kd2 c5 9. Ba3
16 10:40 -2.52 1. a4+ Kb6 2. Rxc5 Kxc5 3. Bg5 Kb4
4. Kf3 Kxa4 5. Ke4 Ka3 6. Bc1+ Ka2
7. Kd3 Kb1 8. Kd2 c5 9. Ba3 c4
16-> 10:52 -2.52 1. a4+ Kb6 2. Rxc5 Kxc5 3. Bg5 Kb4
4. Kf3 Kxa4 5. Ke4 Ka3 6. Bc1+ Ka2
7. Kd3 Kb1 8. Kd2 c5 9. Ba3 c4
17 11:04 -- 1. a4+
time=16:39 cpu=99% mat=5 n=496622998 fh=95% nps=497k
ext-> chk=41894944 cap=17578 pp=745472 1rep=665609 mate=5596
predicted=0 nodes=496622998 evals=0
endgame tablebase-> probes done=71968 successful=71968
Still isn't too wild about it and just failed low. But will a 3 day search
resolve to the draw? Hard to know unless we are really patient.
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