Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Question for Chess Programmers

Author: Peter McKenzie

Date: 22:31:30 12/21/98

Go up one level in this thread


On December 22, 1998 at 01:14:12, Sylvain Lacombe wrote:

>
>>I agree; there are usually a lot of forced mates in a given position, and the
>>first one found is usually NOT the fastest.
>>
>>James
>
>Well, if iterative deepening is implemented, it will find the fastest mate. If a
>mate his found at deep 4, their his no reason to continue the search cause there
>is nothing better than mate. But you need a condition for it to stop.

This isn't quite true.  One point is that you may find the mate in your
Q-search.  So for example, after a depth 4 search you might have a score
indicating mate in 7ply but after a depth 5 search you might find a mate in 5
ply.  This could happen because the move to deliver mate at depth 5 wasn't
looked at by the Q-search (ie. its not a capture or pawn promotion).

I think this sort of thing can only happen if you don't allow standing pat when
in check in the Q-search.

Another factor is null move pruning.  A deeper search may allow a quicker mate
to be exposed that hadn't been seen earlier due to nullmove pruning.

>
>The only thing i can think of for not implementing the PV play is the extra code
>it takes.
>
>Sylvain.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.