Author: Pauli Misikangas
Date: 05:55:34 09/05/99
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On September 05, 1999 at 04:09:58, Pauli Misikangas wrote: >On September 04, 1999 at 22:15:16, Robert Hyatt wrote: > >>The measurement I do inside crafty is to count the number of positions where I >>get a fail-high, and then count the number of positions where I get a fail high >>on the _first_ move I search. I am generally seeing this average about 94%, >>which means 94% of the times when I fail high, I fail high on the first move, >>which is pretty good. > >Have you tested what this "first-fails-high" percentage is when searching to >different depths? In other words, instead of using only one counter for >fail-highs, use one for each depth. So, if you get a fail-high in a node that >was searched to depth d, increase counter fail_high_counter[d] and if the move >was the first one, increase also first_failed_high[d]. What kind of >first-fails-high percentages (100*first_failed_high[d]/fail_high_counter[d]) do >you get for each d? > >In my understanding, finding a fail-high move quickly is much more important in >nodes near the root than in leaf nodes. If you don't count fail-highs separately >for each depth, fail highs in leaf nodes will dominate and hide possible >weaknesses in move ordering near the root. Do you agree? > >If 94% first-fails-high percentage is "pretty good" for a chess program, what >would you expect the percentage to be for a shogi program that has a good move >ordering? In shogi, you have average 80 possible moves per turn while in chess >you have "only" 35. You can find some fail-high statistics of my shogi program ("Shocky") from my web page http://www.cs.helsinki.fi/Pauli.Misikangas/shocky/failhigh.txt Statistics are from a game in which Shocky played against Shotest 3 (3rd best shogi program in the world), and won. :-) Here is a sample of the statistics. For example, the table below shows that I got 235037 fail-highs on the first move when searching to depth 2 and that it was 86.5% of the total fail-highs at that depth. The percentages are accumulative, e.g. in 96% of the fail-highs at depth 1, the fail-high move was within first 6 moves. Move Quiescense Depth 1 Depth 2 ----|---------------------|------------------|------------------| ... 1 : 6507600 93.8% 608743 82.3% 235037 86.5% 2 : 287578 97.9% 63112 90.8% 16116 92.5% 3 : 77930 99.1% 18759 93.3% 5134 94.4% 4 : 28986 99.5% 8833 94.5% 2514 95.3% 5 : 13510 99.7% 6148 95.4% 1910 96% 6 : 8062 99.8% 4812 96% 1562 96.6% 7 : 4496 99.9% 4066 96.6% 1339 97.1% 8 : 2628 99.9% 3429 97% 1125 97.5% 9 : 2447 99.9% 3055 97.4% 924 97.8% 10 : 1544 100% 2650 97.8% 784 98.1% ... Interestingly, the first-fails-high percentages seem to bet better when the depth increases. Is this normal? Best, Pauli Misikangas
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