Author: Christophe Theron
Date: 11:05:24 06/01/00
Go up one level in this thread
On May 31, 2000 at 18:57:38, Tom Kerrigan wrote:
>On May 31, 2000 at 18:02:42, Bas Hamstra wrote:
>
>>Tom,
>>
>>I read another thread about Killers and have an opinion on it.
>>
>>- Doing captures separately speeds you up considerably
>
>Depends on what you mean by "considerably." I'm doing a full width search on
>~10% of the nodes that I search. So the speedup that I can expect is
>significantly less than 10%.
I understand from this that 90% of your nodes are in QSearch? Right?
In any case, better ordering of 10% of your moves can give a speedup higher than
10%.
Better move ordering can actually give you more cutoffs later in the tree. Move
ordering actually has an impact on the whole subtree, and all the subtrees
searched after.
For example, searching just ONE node out of order at the root of the search can
easily double your tree size.
Christophe
>>- Doing an on the fly legality check for killers speeds you up noticably
>
>Not if you've already generated them. :)
>
>>- Doing SEE based pruning of losing captures in the qsearch cuts the number of
>>nodes and improves node/qnode ratio. You don't have to SEE sort for it. I doubt
>>SEE sorting is a winner anyway.
>
>I've used SEE for a long time and I haven't been extremely happy with it. It's
>not in my experimental program.
>
>>- Having the former, you can skip losing captures in the normal search as well
>>with it, and do those later. Improves sorting noticably.
>
>In my previous programs, using the SEE to order moves had a speedup of 10%.
>
>-Tom
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