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Subject: Re: root move ordering

Author: Tony Werten

Date: 03:37:33 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".

If you want exact science, don't get involved in computerchess :)

But seriously, I don't think it matters much while the bestmove stays constant.
Maybe slightly better killermoves, maybe slightly better hash cutoffs, but I
doubt it's significant.

After a faillow however, finding the new bestmove at 2nd place will be a lot
nicer than failing high on move 2, resolving it, failing high on move 3
resolving it, etc.

But coming back to exact science, I don't think it will be more than ..., say ..
, eh .. 15 ELO ? ( with an uncertainty of +-50%)

Tony

>
>cheers
>  martin



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