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Subject: Re: Bitboards and Quick Killer

Author: Andrew Dados

Date: 13:56:21 08/16/00

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On August 15, 2000 at 19:24:25, Tom Kerrigan wrote:

>On August 15, 2000 at 18:33:26, Larry Griffiths wrote:
>
>>On August 15, 2000 at 17:03:24, Tom Kerrigan wrote:
>>
>>>On August 15, 2000 at 13:43:55, Larry Griffiths wrote:
>>>
>>>
>>>No matter how you generate your moves, you should always be searching captures
>>>before killers.
>>>
>>>Also, at this early stage in your program's development, you should just
>>>generate all your moves at once and move on. Doing this "quick killer" stuff
>>>doesn't give you a very big performance gain and it makes your code much more
>>>complicated.
>>>
>>>-Tom
>>
>>I am using a lot of code concepts from my previous chess program.
>>This program is more object-oriented and uses bitboards heavily.
>>My "quick killer" code reduces the search time up to 50% and I consider
>>that a very good performance gain.
>
>That sounds odd to me.
>
>About 80-90% of your nodes should be in q-search, where you don't have to
>generate killers. So the most you can possibly hope for from "quick killer"
>stuff is 10-20% (and that obviously won't be achieved...).
>
>-Tom

A well written qsearch shouldn't use more then 60% total nodes imo.

Note a 'paradox' : if you can cut qsearch nodes by less then half from 90% down
to 50% your program overall speedup is up to 5 times (non qsearch nodes go up
from 10% to 50% of all).

-Andrew-



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