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Subject: Re: Selective Searching

Author: Don Dailey

Date: 09:48:44 02/07/98

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Hi Stuart,

Your post confuses me.  You asked about selective searches and then I
find out you know all about it.   But then you want info on Langs search
and we have just posted all kinds of stuff on this.  The bottom line is
that we do not know,  we just have some specualtions.  Re-read the posts
of the last month or so.

If you are looking for some secret techique everyone but you knows
about, then I'm not aware of any.  Everyone has their own little bag of
tricks they swear by and any single one is probably not worth much by
itself.  To write a strong program you must do a lot of things slightly
better than the others!  When I figure out how I'll let you know!

I'm always looking for the mythical 1 line change that add 100 rating
points to the program but haven't found it yet (except when it's taking
out the latest bug!)

- Don

P.S.  It is unclear whether Langs search "secrets" are any better than
good null move pruning.  His program is impressive (and different) but
seems to be in the same league as the other top 4 or 5, most of which
use null move prunning.



On February 06, 1998 at 20:23:44, Stuart Cracraft wrote:

>On February 06, 1998 at 18:44:35, Don Dailey wrote:
>
>>On February 06, 1998 at 14:02:11, Stuart Cracraft wrote:
>>
>>>A number of years ago, commercial programs like Lang's, and others
>>>seemed to get about 100 points stronger due to being selective
>>>searchers over their brute-force full-width, with capture quiescence
>>>counterparts.
>>>
>>>Is this true? If so, what are the nature of the changes involved?
>>>
>>>Thanks,
>>>Stuart
>>
>>Hi Stuart,
>>
>>You need to know about null move searching if you are writting a chess
>>program. There are some good articles in ICCA past issues and you should
>>definitely try to dig them up.  Just about every program now uses it but
>>there are a few exceptions.    No one knows for sure what Richard Lang
>>does but it's likely to involve similar ideas.   If you want I can send
>>you the basic idea and some psuedo code.
>>
>>- Don
>
>I do use null move currently and wouldn't be without it. Have been
>using it for quite a while. No problem with it. Quite a few exceptions
>for when it is not used though and I think I have a number of them.
>
>Sure, send anything you might be illustrative.
>
>--Stuart



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