[Discussion] - Measuring move ordering

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Cardoso
Posts: 275
Joined: Thu Mar 16, 2006 6:39 pm

Re: [Discussion] - Measuring move ordering

Post by Cardoso » Fri Mar 02, 2018 6:03 pm

Another thing to take into consideration is the position specificity, I mean on equal positions with high probability of changing the best move several times you might get worse move ordering.
On sharp/winning positions you get much better move ordering.
But I suspect you already know that :wink:

Aleks Peshkov
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Location: Russia

Re: [Discussion] - Measuring move ordering

Post by Aleks Peshkov » Mon Mar 05, 2018 10:18 am

There is a true metric: ratio of nodes pruned relative to full minimax tree.

jdart
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Location: http://www.arasanchess.org

Re: [Discussion] - Measuring move ordering

Post by jdart » Mon Mar 05, 2018 3:11 pm

The stats I have are over the whole search tree (excluding qsearch), not just for the root. The character of the position will likely change as the search progresses deeper.

--Jon

Cardoso
Posts: 275
Joined: Thu Mar 16, 2006 6:39 pm

Re: [Discussion] - Measuring move ordering

Post by Cardoso » Mon Mar 05, 2018 10:56 pm

Jon, my stats also come from the whole search tree except qsearch.
What I have observed is that an equal and unstable position (several changes in the best move) at the root usually gives poorer FH ratios like for example 82%8%2%1%.
And a winning stable position usually gives much better FH ratios, usually something like 95%2%1%0% and sometimes even something like 98%1%0%0%.
Notice I've used the word usually, there are many exceptions.
Engines are different of course, and mine is even more different since it is a checkers engine.

Cardoso
Posts: 275
Joined: Thu Mar 16, 2006 6:39 pm

Re: [Discussion] - Measuring move ordering

Post by Cardoso » Mon Mar 05, 2018 11:01 pm

I understand.
But these days with such agressive alphabeta LMR/LMP/Razoring/Futility, etc, the tree get so different from the minimax tree that is almost impossible to do that true metric you suggested.

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