Author: Uri Blass
Date: 10:18:00 06/05/04
Go up one level in this thread
On June 05, 2004 at 13:01:34, Will Singleton wrote: >On June 05, 2004 at 12:53:53, Uri Blass wrote: > >>On June 05, 2004 at 12:32:47, Will Singleton wrote: >> >>>On June 05, 2004 at 10:13:35, Anthony Cozzie wrote: >>> >>>>On June 04, 2004 at 19:03:53, Anthony Cozzie wrote: >>>> >>>>>From Yace-Zappa >>>>> >>>>>[D]3q1rk1/pp1bppbp/3p1npB/8/2rNP1P1/2N2P2/PPPQ4/2KR3R b - - 0 16 >>>>> >>>>>1... Nf6xe4 2. f3xe4 Bg7xd4 3. Qd2-d3 b7-b5 4. Nc3-d5 Bd4-e5 5. Bh6xf8 Qd8xf8 6. >>>>>g4-g5 Qf8-g7 7. c2-c3 Rc4-a4 8. Kc1-b1 Kg8-f8 >>>>> = (0.32) Depth: 15/38 00:06:02.03 263847kN >>>>> >>>>>The game continued Nxe4 Qe3 Rxc3 bxc3 Qh6 Nf6 and now your program should be >>>>>able to see g5! and white is able to win the queen. >>>>> >>>>>Anyone out there that can avoid Nxe4 in reasonable time? >>>>> >>>>>anthony >>>> >>>>OK, as has been pointed out by about 25 people, the mistake is not Nxe4, but >>>>Bxh6 (a move which somehow I conviently omitted from the my line). >>>> >>>>[D]3q1rk1/pp1bppbp/3p2pB/8/3Nn1P1/2P1QP2/P1P5/2KR3R b - - 0 18 >>>> >>>>Even this one is pretty hard for Zappa, it needs 70 seconds to realize Bxh6 is >>>>losing and 6 minutes switch to Nf6. >>>> >>>>1... Bg7xh6 2. Rh1xh6 Ne4-f6 3. Rd1-h1 e7-e5 4. Nd4-f5 Bd7xf5 5. g4xf5 Qd8-a5 6. >>>>Qe3-g5 Qa5-a3 7. Kc1-d1 Kg8-g7 8. f5xg6 f7xg6 >>>> = (0.50) Depth: 14/31 00:00:46.41 37517kN >>>>1 ...Bg7xh6-- >>>> - (0.25) Depth: 15/30 00:01:08.74 55010kN >>>>1... Bg7xh6 2. Qe3xh6 Ne4-f6 3. g4-g5 Nf6-h5 4. Rh1xh5 g6xh5 5. Rd1-h1 Qd8-a5 6. >>>>Rh1xh5 Bd7-f5 7. Nd4xf5 Qa5xf5 8. g5-g6 Qf5xg6 9. Rh5-g5 Rf8-c8 10. Rg5xg6 h7xg6 >>>> = (-2.83) Depth: 15/34 00:03:02.47 147329kN >>>>1... Ne4-f6 2. Bh6xg7 Kg8xg7 3. Nd4-f5 Bd7xf5 4. g4xf5 Qd8-a5 5. Qe3xe7 Qa5xa2 >>>>6. Qe7xb7 Qa2-a3 7. Qb7-b2 Qa3-c5 8. f5xg6 f7xg6 9. Rh1-e1 Rf8-c8 10. Re1-e7 >>>>Kg7-h6 >>>> = (0.18) Depth: 15/36 00:05:34.28 269390kN >>>> >>>>anthony >>> >>> >>>The time it takes to find Nf6 after seeing the problem with Bxh6 is rather long >>>for some programs. For example, Crafty (3 min), Ruffian (1:30) and Zappa >>>(2:30). This is because the problem occurs at a high search depth. >>> >>>Amateur does better in switching to the right move, taking only 10 sec. It does >>>this by "cheating," which is to say, reducing the search depth when a large >>>score drop occurs. I don't really see a downside to this. >>> >>>Crafty >>>14 191 11683 124623699 1. ... Bxh6 2. Qxh6 Nf6 >>>14 16 30945 341466474 1. ... Nf6 2. Bxg7 Kxg7 >>> >>>Ruffian >>>14 -161 10004 121228508 Bxh6 Qxh6 Nf6 >>>14 -5 18402 223090636 Nf6 Bxg7 Kxg7 >>> >>>Amateur >>>16 -243 12517 49364251 Bxh6 Qxh6 Nf6 >>>13 -243 12517 49364252 Bxh6 >>>13 87 13581 53146356 Nf6 Bxg7 Kxg7 >> >> >>all these programs do better than movei that cannot get so deep. >>Movei find at depth 14 that Bxh6 is bad but it takes it clearly more time and >>even more nodes(movei is relatively slow searcher). >> >>Note that movei has no threat mate extensions and I suspect that threat mate >>extensions can help to find that Bxh6 is bad at least one ply earlier. >> >>Uri > >OK, but do you have a comment regarding the point of my post? Here is movei's analysis on A1000(64 mbytes hash) 13 8 44893 84863341 g7h6 h1h6 e4f6 g4g5 f6h5 d4b3 f7f6 g5f6 f8f6 e3a7 d8f8 h6h5 g6h5 a7b7 14 -233 108410 203785129 g7h6 e3h6 e4f6 g4g5 f6h5 h1h5 g6h5 d1h1 d8a5 h1h5 d7f5 d4f5 a5f5 g5g6 f5g6 h5g5 f8c8 g5g6 f7g6 14 -232 149797 276778309 e4f6 14 -203 156552 291129800 e4f6 You can see that even if you look only at the time between Bh6 and failing high the time is not good and more than 400 seconds on A1000 is still more than 2 minutes on fast hardware and it is not all the story. Movei's policy today is not to believe fail high unless it solves them because they may be wrong fail high. It means that if movei has not enough time to solve the fail high of Nf6 it will play Bxh6 I will probably change it in the future but in games it is not very important because in most of the cases movei has time to solve fail high problems. Uri
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