Author: Will Singleton
Date: 17:29:29 10/03/05
Go up one level in this thread
On October 03, 2005 at 17:24:41, Robert Hyatt wrote: >On October 03, 2005 at 16:04:51, Will Singleton wrote: > >>On October 03, 2005 at 11:43:22, Robert Hyatt wrote: >> >>>On October 02, 2005 at 13:49:37, Will Singleton wrote: >>> >>>>White wins easily by promoting and exchanging queens, but most comps can't see >>>>it. >>>> >>>>[d]8/5p1P/8/8/6K1/5P2/1k6/q7 w - - >>>> >>>>Amateur failed to exchange queens, and drew the game. I'm not quite sure why, >>>>seems like a simple search should be enough to handle this. Oddly, if the >>>>exchange is forced, the win is seen immediately. This happens with other progs >>>>as well. I thought I had taken steps to eliminate root-position dependencies in >>>>the search, but maybe something else is happening. >>>> >>>>Will >>> >>> >>>Here is what you need: >>> >>>Your program probably understands that if you remove the black queen, white is >>>winning because of the "outside passed pawn"??? (ignore the fact that the pawn >>>promotes instantly for now). If so, you need one more critical piece of >>>knowledge. >>> >>>Your program needsd to realize that if things are not obvious, no pawn to >>>promote, no distant passer on the board, but its king is closer to the remaining >>>pawns than the enemy king, the game is _still_ won. >>> >>>Set up a position like white/black pawns locked up at a4/a5, white passer at h2, >>>both kings near the center of the board. The easiest way to win is to push the >>>h-pawn. Black has to go over and stop it, and once it is gone, white is too >>>close to the remaining black a-pawn and the game is over. >>> >>>If you don't catch this case, you will play for a distant passer, but then >>>refuse to give it up, and once your king gets to the distant passer to defend >>>it, you can't force the promotion, and when you wait too long, as your king >>>finally gives up the passer, black eats it and then follows you across the board >>>and hems in your king on the a-file or else black gets to the a-file and the >>>game is a draw. But if you just push and get the black king too far away, you >>>win easily... >>> >>>Crafty plays this move instantly with no endgame tables of any kind, and shows a >>>big +score for white immediately, due to the above... >>> >>> >> >>Thanks for the info, it will be helpful in other situations. This one is >>different. After h8=Q a1=Q, we get this position: >> >>[d]7Q/5p2/8/8/6K1/5P2/k7/q7 w - - >> >>From here, Crafty takes 15 ply (over a minute on my comp) to see the exchange, >>then another ply to get a winning score. This is the problem I was referring >>to, albeit clumsily. >> >>Will > > >Here is crafty's output on my box, no endgame tables of any kind: > > 3 0.07 1.84 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Ke5 > 3-> 0.08 1.84 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Ke5 > 4 0.09 +1 1. Qxa1+!! > 4 0.10 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. Kxf7 > 4-> 0.12 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. Kxf7 > 5 0.14 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. Kxf7 > 5-> 0.16 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. Kxf7 > 6 0.18 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. f4 Kd3 5. Kxf7 > 6-> 0.20 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. f4 Kd3 5. Kxf7 > 7 0.22 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. f4 Kd3 5. Kxf7 > 7-> 0.24 2.82 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. f4 Kd3 5. Kxf7 > 8 0.26 2.72 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. f4 Kd3 5. Kxf7 Ke4 > 8-> 0.31 2.72 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. Kf6 Kc2 > 4. f4 Kd3 5. Kxf7 Ke4 > 9 0.32 -1 1. Qxa1+ > 9 0.34 1.66 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. f4 Kc2 > 4. Ke5 Kd3 5. f5 Ke3 6. f6 > 9-> 0.48 1.66 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. f4 Kc2 > 4. Ke5 Kd3 5. f5 Ke3 6. f6 > 10 0.51 1.30 1. Qxa1+ Kxa1 2. Kg3 Kb2 3. Kf2 Kb3 > 4. f4 Kc3 5. Ke1 Kd3 6. f5 Ke3 > 10-> 2.90 1.30 1. Qxa1+ Kxa1 2. Kg3 Kb2 3. Kf2 Kb3 > > >And it never changes its mind... > >It is certainly possible that you have a version with an evaluation bug. I have >been going over the thing line by line, and have completely re-vamped its >"organization" before we start a complete "re-do" of many features, particularly >king safety. But it should always trade queens, so long as the endgame code is >being utilized correctly, as above.... Odd. I'm using the 20.0 BH 32-bit compile, 96mb hash. Here's the output from winboard: 24828 >first : analyze 24843 <first : Analyze Mode: type "exit" to terminate. 25625 <first : 9 138 79 1139276 1. Qa8+ Kb2 2. Qb7+ Kc2 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 <HT> 26140 <first : 10 136 131 1907238 1. Qa8+ Kb2 2. Qb7+ Kc2 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Kg7 <HT> 26718 <first : 10 136 189 2732686 1. Qa8+ Kb2 2. Qb7+ Kc2 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Kg7 <HT> 26843 >first : . 27640 <first : 11 136 281 4087310 1. Qa8+ Kb2 2. Qb7+ Kc2 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Kg7 Qe5+ 10. Qf6 Qd5 28843 >first : . 28859 <first : 11 136 403 5874947 1. Qa8+ Kb2 2. Qb7+ Kc2 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Kg7 Qe5+ 10. Qf6 Qd5 34718 <first : 12 124 989 14769539 1. Qa8+ Kb2 2. Qb7+ Kc3 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Qh5 Qf4+ 10. Kg6 Qd6+ 11. Kg5 Kd2 39015 <first : 12 124 1418 21059912 1. Qa8+ Kb2 2. Qb7+ Kc3 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Qh5 Qf4+ 10. Kg6 Qd6+ 11. Kg5 Kd2 43890 <first : 13 124 1906 28434837 1. Qa8+ Kb2 2. Qb7+ Kc3 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Qh5 Qf4+ 10. Kg6 Kd3 11. Qg4 Qe5 49375 <first : 13 124 2454 36483094 1. Qa8+ Kb2 2. Qb7+ Kc3 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Qh5 Qf4+ 10. Kg6 Kd3 11. Qg4 Qe5 76218 <first : 14 118 5139 75528628 1. Qa8+ Kb2 2. Qb7+ Kc3 3. Qxf7 Qg1+ 4. Kf5 Qc5+ 5. Kg6 Qg1+ 6. Kf6 Qd4+ 7. Kg5 Qg1+ 8. Kh6 Qh2+ 9. Kg7 Qg3+ 10. Kh8 Qh3+ 11. Kg8 Kd3 12. f4 Ke2 96406 <first : 14 164 7157 105056493 1. Qxa1+!! 96422 <first : 14 180 7159 105069619 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. f4 Kc2 4. Ke5 Kd3 5. f5 Ke3 6. f6 Kd3 7. Kd6 Kd4 8. Ke7 Ke5 9. Kxf7 96437 <first : 14 180 7159 105076538 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. f4 Kc2 4. Ke5 Kd3 5. f5 Ke3 6. f6 Kd3 7. Kd6 Kd4 8. Ke7 Ke5 9. Kxf7 96437 <first : 15 180 7160 105094633 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. f4 Kc2 4. Ke5 Kd3 5. f5 Ke3 6. f6 Kd3 7. Kd6 Kd4 8. Ke7 Ke5 9. Kxf7 135218 <first : 15 180 11039 165103321 1. Qxa1+ Kxa1 2. Kf5 Kb1 3. f4 Kc2 4. Ke5 Kd3 5. f5 Ke3 6. f6 Kd3 7. Kd6 Kd4 8. Ke7 Ke5 9. Kxf7 135218 <first : 16 220 11039 165115199 1. Qxa1+!! 135234 <first : 16 320 11040 165126491 1. Qxa1+!! 135234 <first : 16 520 11040 165141365 1. Qxa1+!! 135265 <first : 16 442 11043 165169592 1. Qxa1+ Kxa1 2. Kf5 Kb2 3. f4 Kc3 4. Ke5 Kd3 5. f5 Ke3 6. f6 Kd3 7. Kd6 Ke3 8. Ke7 Ke4 9. Kxf7 Ke5 10. Ke7 <HT>
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