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Subject: Re: Root move ordering - an experiment

Author: Robert Hyatt

Date: 11:07:52 09/28/04

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On September 28, 2004 at 13:43:48, Stuart Cracraft wrote:

>On September 28, 2004 at 08:44:04, martin fierz wrote:
>
>>On September 28, 2004 at 08:19:15, Stuart Cracraft wrote:
>>
>>>On September 28, 2004 at 02:14:51, martin fierz wrote:
>>>
>>>>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
>>>>
>>>>...as ed schröder said to me: "terrible testing". he was right, of course.
>>>>
>>>>cheers
>>>>  martin
>>>
>>>Each to his own.
>>
>>if you get free advice from one of the world's best computer chess programmers
>>it is a good idea to use it. there's not much point writing tons of posts here
>>asking for advice if you don't listen....
>>
>>cheers
>>  martin
>
>Well, condemnations aside, without specific feedback beyond "Oh that's just
>bad" (I can get that at work from the boss or from relatives) -- I don't
>respond well to that kind of input. It is non-constructive.
>
>Specific constructive feedback, regardless of the person's perceived or
>actual stature please.
>
>Stuart

Here is what is bad:

You are searching for 1 second per position.  Exactly how accurate do you think
that one second time interval is?  Probably +/- .1 seconds or so.  So you
introduce a random variability because your time error is a major fraction of
the total time used.  If you search for 60 seconds, the operating system won't
introduce nearly as much error (still +/- .1 second or whatever it really is)
and that error percentage is small enough that it will not introduce nearly as
much random noise.

1 second is simply NFG.  At least you should make it 1 sec + complete current
iteration before stopping.  And that might not be good enough on such short
searches...




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