Author: Dann Corbit
Date: 11:03:50 09/14/00
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On September 14, 2000 at 13:42:49, Ed Schröder wrote: >In the upcoming Rebel Century 3.0 I have implemented a little >statistic routine that reveals something about the nature of SEARCH >that could be important for the future of computer chess in the sense >that it says "something" one may expect in the near future because >of faster and faster PC's. > >Research on this issue have already been done by Bob and Ernst and >it has made me curious so I have spend a little time on it. The >statistic shows 2 things: > >a) number of fail-low's for each depth; >b) number of "changed moves" for each depth. > >(a) is not so important as often fail-low's do not mean anything but I >wanted to know anyway. > >(b) is extremely important as it shows for each depth how many times >Rebel changed its mind. As you can see in the below statistic the % >diminish and diminish the deeper Rebel goes. > >How to read the overview: >- first column: iteration depth; >- second column: number of times the depth was reached; >- third column: number of fail-low's; >- fourth column: percentage of fail-low's; >- Fifth column: number of changed moves; >- Last column: percentage of changed moves; > >SEARCH OVERVIEW >=============== > >1 4726 0 ( 0) 0 ( 0) >2 4726 1000 (21) 1889 (39) >3 4726 495 (10) 1468 (31) >4 4719 209 ( 4) 1085 (22) >5 4719 218 ( 4) 1222 (25) >6 4699 191 ( 4) 1139 (24) >7 4655 141 ( 3) 948 (20) >8 4572 109 ( 2) 837 (18) >9 4457 79 ( 1) 777 (17) >10 3998 86 ( 2) 644 (16) >11 3015 64 ( 2) 374 (12) >12 1904 55 ( 2) 204 (10) >13 1093 37 ( 3) 77 ( 7) >14 584 22 ( 3) 35 ( 5) >15 356 15 ( 4) 22 ( 6) >16 230 7 ( 3) 6 ( 2) >17 157 6 ( 3) 2 ( 1) >18 123 6 ( 4) 3 ( 2) >19 88 0 ( 0) 0 ( 0) >20 67 0 ( 0) 1 ( 1) >21 55 0 ( 0) 1 ( 1) >22 54 0 ( 0) 1 ( 1) >23 50 0 ( 0) 0 ( 0) >24 47 0 ( 0) 0 ( 0) >25 40 0 ( 0) 0 ( 0) >26 30 0 ( 0) 0 ( 0) >27 28 0 ( 0) 0 ( 0) >28 22 0 ( 0) 0 ( 0) >29 19 0 ( 0) 0 ( 0) >30 14 0 ( 0) 0 ( 0) >31 14 0 ( 0) 0 ( 0) >32 13 0 ( 0) 0 ( 0) >33 12 0 ( 0) 0 ( 0) >34 12 0 ( 0) 0 ( 0) >35 10 0 ( 0) 0 ( 0) >36 10 0 ( 0) 0 ( 0) >37 10 0 ( 0) 0 ( 0) >38 10 0 ( 0) 0 ( 0) >39 10 0 ( 0) 0 ( 0) >40 8 0 ( 0) 0 ( 0) >41 8 0 ( 0) 0 ( 0) >42 5 0 ( 0) 0 ( 0) >43 4 0 ( 0) 0 ( 0) >44 3 0 ( 0) 0 ( 0) >45 3 0 ( 0) 0 ( 0) >46 2 0 ( 0) 0 ( 0) >47 2 0 ( 0) 0 ( 0) >48 2 0 ( 0) 0 ( 0) >49 2 0 ( 0) 0 ( 0) >50 2 0 ( 0) 0 ( 0) >51 2 0 ( 0) 0 ( 0) >52 2 0 ( 0) 0 ( 0) >53 2 0 ( 0) 0 ( 0) >54 2 0 ( 0) 0 ( 0) >55 2 0 ( 0) 0 ( 0) >56 2 0 ( 0) 0 ( 0) >57 2 0 ( 0) 0 ( 0) >58 2 0 ( 0) 0 ( 0) >59 2 0 ( 0) 0 ( 0) >60 2 0 ( 0) 0 ( 0) > >After iteration 19 one hardly sees any changes. One might wonder >if a doubling in speed is still good for 50-70 elo (as often said >here). > >One thing that should be added to the overview is a division in >middle-game and end-game (I think). > >The overview was created by playing a 40/40 auto232 match (about >50 games). Results are automatically kept so that a next auto232 >match the statistic is automatically updated. > >Also if you are playing your normal (manual) games or analyze positions >the statistic is maintained. It would be nice to see how the statistic >would look like after say 100,000 moves. I think this is a fantastic idea. When analyzing an EPD position, I think "depth of last change" might be nice for a comment (c3 or something). This would be especially helpful to know when a position might trip up an opponent. I disagree that we can form an opinion about the value of deeper searches at this point. The reason I make a bold and silly statement like that despite your clear evidence is the sort of searches that will give 60 plies depth. If we were able to achieve 60 plies from the opening position, I think that is far more valuable than 60 plies in the deep endgame. I suspect that none of the positions searched very deeply were complicated board positions with many possiblilities for alternatives. When we are in the opening, middle game, or early endgame, I think these are the places where deep searches are valuable. If you have only 7 pieces left on the board, there are not that many possibly good choices. Of course, I could be completely wrong. But I think another valuable column would be "piece count" so that we could do queries based not only on depth but also upon complication. Your ideas are very inventive and creative. No wonder you produce such a wonderful product. -- Dann "Slavering for a Win32 EPD analyzer version of Rebel" Corbit
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