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Subject: Re: To check or not to check, this is the quiescence question

Author: Uri Blass

Date: 08:01:09 10/14/03

Go up one level in this thread


On October 14, 2003 at 10:55:51, Robert Hyatt wrote:

>On October 14, 2003 at 10:31:49, Tord Romstad wrote:
>
>>On October 14, 2003 at 10:06:41, Robert Hyatt wrote:
>>
>>>On October 14, 2003 at 08:42:05, Tord Romstad wrote:
>>
>>>>I think it is a good idea to use the SEE for checking moves, too.  Only search
>>>>checks which do not lose material.
>>>
>>>Then you admit defeat before you start.  See the simple draw by stalemate
>>>idea where you have a king and rook, and your king can't move.  You just
>>>make unsafe check after unsafe check because the rook can't be taken.
>>
>>I don't see how not searching losing checks in the qsearch is admitting defeat
>>any more than not searching losing captures is.  In both cases, you will make
>>mistakes, but also save lots of time.
>
>That's the point.  "admitting defeat" means "accepting additional errors".
>
>I wasn't talking about losing games, specifically.  The q-search based only
>on captures if _full_ of errors.  It fails to understand any tactic except
>those specifically depending on captures.  IE no pins.  No threats.  No
>double attacks.  No skewers.  No checks.
>
>If you add safe checks, that is a small part of the above list of things it
>will overlook.  A part small enough that it probably won't help much, and
>it might hurt if it wastes too much time.
>
>Perhaps my "admitting defeat" was too vague a descriptive term??
>
>
>>
>>>Safe checks are probably better than no checks, assuming you believe you
>>>have to do checks in the q-search.  But, as I have said so many times, if
>>>your q-search is going to have so many holes, find a way to avoid putting
>>>such a heavy responsibility on the q-search in the first place.
>>
>>Sure.  I wish I could get good results with a minimalistic qsearch like
>>yours.  Unfortunately it never worked very well so far.  But perhaps
>>Omid is right that a minimalistic qsearch works better with nullmove
>>R=2 than with R=3 (which I use).  I will run some experiments with R=2
>>and no checks in qsearch when I find the time.
>>
>>Tord
>
>I use R=3 to R=2, and I really haven't seen anything bad.

bad is something relative.

My guess is that Crafty can be better with the right implementation of checks
in the qsearch.

Uri



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