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Subject: Re: Root move ordering - an experiment

Author: Robert Hyatt

Date: 20:53:09 09/27/04

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On September 27, 2004 at 23:45:54, Stuart Cracraft wrote:

>I experimented with reordering root ply at iterative depth iply >  1
>where 1 is the root ply, with the results of iply-1 sorted by the
>total nodes of quiescence and main search defined as the # of entries
>for each of those subroutines.
>
>I didn't sort at root node on the first sort by quiescence but instead
>by my normal scheme though I tried quiescence and it was worse. I felt
>this gave a better chance to the above method.
>
>I sorted moves at the root ply for iply > 1 in the following way
>for 7 different parts to the experiment.
>
>   sort by normal method (history heuristic, mvv/lva, see, etc.
>   sort exactly by subtree node count, nothing else
>   sort by subtree node count added to normal score (hh, mvv/lva, see, etc.)
>   same as previous but node count x 10 before addition
>   same as previous but node count x 100 before addition
>   same as previous but node count x 1000 before addition
>   same as previous but node count x 10000 before addition
>
>The results, measured by # right on Win-at-Chess varied from
>250 for the first in the list above to 234 for the last.
>Most bunched up between 244-247 except the first was 250,
>my current best on WAC with handtuning everything.
>
>For me, I'm convinced that this style of sorting root ply is
>slightly less good for my short searches compared to what I am using:
>a combination of history, heuristic, see(), and centrality with
>various bonuses, about a half page of code sprinkled about.
>
>The advantage  of sorting root node by subtree is the simplicity.
>It eliminates about a half a page of code and introduces
>about a quarter page of code for only slightly lesser results
>(within 1-2% of my current result) so that is good.
>
>Still I think I'll leave it #ifdefed out for now and use it as
>a baseline that is only improvable upon with handtuning of my
>current methods and others to be discovered.
>
>Stuart



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