Author: Pauli Misikangas
Date: 05:55:34 09/05/99
Go up one level in this thread
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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