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Subject: Re: root move ordering

Author: Stuart Cracraft

Date: 09:23:23 09/23/04

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On September 23, 2004 at 05:10:40, martin fierz wrote:

>On September 23, 2004 at 04:14:15, Tony Werten wrote:
>
>>On September 23, 2004 at 04:10:18, martin fierz wrote:
>>
>>>[snip]
>>>
>>>>There is _no_ overhead.  It is done only at the root, once per iteration.  For a
>>>>12 ply search, a total of 12 times.  That won't use measurable CPU time.  The
>>>>point is that root move ordering is critical for efficiency..
>>>
>>>exactly how critical for efficiency would you believe it to be?
>>
>>Depends on the bestmove. If that is constant, it's less important than after a
>>rootfaillow.
>>
>>Tony
>
>ha! what kind of an answer is that :-)
>
>seriously though: it's clear that there is some importance to it, but can
>anybody quantify it? e.g. like this: "ordering root moves by size of subtrees
>gains X elo compared to constant static ordering done at ply 1".
>
>cheers
>  martin

I would like to comment that I don't see what the point of ordering
by subtree size is. That subtree is already searched. There is no
flowover to other subtrees of brother moves at ply 0 to benefit those
brothers.

That is why when I experimented today with a ply == 0 resort after each
move is searched that I resorted with the new history heuristic table.

I got a very slight increase in problems solved (2 out of 300) with
a slight 2% drop in total nodes searched.

Stuart





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