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Subject: Re: Measure of moveorder quality

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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