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Subject: Re: Bitboards and Quick Killer

Author: Tom Kerrigan

Date: 16:05:36 08/16/00

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On August 16, 2000 at 16:56:21, Andrew Dados wrote:

>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).

I think you're counting qsearch nodes differently than me. The way I count them,
I believe it's impossible to be < 60%.

-Tom



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