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Subject: Re: A Question on simple Alpha-Beta versus PVS/Negascout

Author: Andrei Fortuna

Date: 17:57:02 03/23/00

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On March 22, 2000 at 14:27:45, Ernst A. Heinz wrote:

>Hi Andrei,
>>In my chess program Freyr I've used simple alpha beta from the start, each time
>>I tried to change it to pvs/negascout it didn't work as expected because it
>>just generated too many nodes. Does anyone else experienced this behavior ?
>>Is there a logical explanation for this ?
>PVS requires good move ordering to work well. Otherwise, the frequent
>researches kill its performance.
>Assuming that your PVS implementation is okay, I would conjecture that
>your move ordering represents the limiting factor here.

I found my problem.
My move ordering is not very bad, but I had a bad quiescence function which was
sometimes bailing out too soon. I rewrote it and now pvs performs better than
plain AB.

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