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Subject: Re: Measure of moveorder quality

Author: Pauli Misikangas

Date: 01:09:58 09/05/99

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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.

All the best,

Pauli Misikangas



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