Author: Robert Hyatt
Date: 10:29:36 12/12/03
Go up one level in this thread
On December 12, 2003 at 12:38:26, Omid David Tabibi wrote: >On December 12, 2003 at 09:28:00, Robert Hyatt wrote: > >>On December 12, 2003 at 03:36:47, Omid David Tabibi wrote: >> >> >>> >>>I had similar problems in Falcon. I fixed the problem by storing the checkmate >>>score as a bound only. Not an efficient solution of course, but haven't >>>encountered any such bugs ever since. >> >> >>There is no need to cripple the search by not storing mate scores at all. >>Adjusting mate scores to not have such problems is very simple, as the >>following output shows: >> >> >> >> depth time score variation (1) >> 8 0.12 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 >> 8-> 0.12 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 >> 9 0.22 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 >> 9-> 0.22 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 >> 10 0.39 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 6. Qf8 >> 10-> 0.39 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 6. Qf8 >> 11 0.76 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 6. Qf8 Ka1 >> 11-> 0.76 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 6. Qf8 Ka1 >> 12 1.34 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 6. Qf8 Ka1 7. Kf6 >> 12-> 1.34 10.19 1. ... Kb6 2. Qg8 Ka5 3. Qf8 Ka4 4. >> Qh8 Ka3 5. Qg8 Kb2 6. Qf8 Ka1 7. Kf6 >> 13 1.87 -- 1. ... Kb6 >> 13 2.75 Mat09 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qd5 Ka7 7. Kc6 >> Kb8 8. Qd8+ <HT> >> 13-> 2.83 Mat09 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qd5 Ka7 7. Kc6 >> Kb8 8. Qd8+ <HT> >> 14 3.63 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 14-> 3.64 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 15 4.87 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 15-> 5.08 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 16 6.77 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 16-> 7.10 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 17 9.22 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 17-> 9.79 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 18 12.45 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 18-> 13.21 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 19 15.82 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 19-> 16.49 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 20 19.52 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 20-> 20.40 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 21 23.41 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 21-> 24.31 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 22 27.33 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 22-> 28.67 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 23 31.75 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 23-> 32.87 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 24 36.13 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 24-> 37.41 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 25 40.49 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 25-> 41.71 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 26 44.83 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 26-> 46.10 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 27 49.29 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 27-> 50.60 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 28 53.73 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 28-> 55.01 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 29 58.11 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 29-> 59.60 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 30 1:02 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 30-> 1:04 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 31 1:07 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 31-> 1:08 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 32 1:11 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 32-> 1:13 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> 33 1:16 Mat08 1. ... Kb6 2. Qh5 Ka6 3. Kf6 Kb6 4. >> Ke6 Ka6 5. Kd6 Kb6 6. Qc5+ Kb7 7. Qb5+ >> Ka7 8. Kc7 Ka8 9. Qb8# >> <etc> >> >>Shredder has a _serious_ bug in hashing somewhere. > >There are two ways to solve a problem: find a good solution, or erase the >problem :) I agree. But not storing exact mate scores is not (a) find a good solution. I don't know where the urban legend that you can't safely store mate scores came from, but it is false. I've been storing mate scores in my trans/ref table since the middle 1970's. Everyone else I knew back then did so as well. Why it would suddenly cause problems is a mystery, but why those problems are not solved is a _real_ mystery. IE as you can see from my output above, I don't see any funny-business with mate scores. Never have, in fact...
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