Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: A question about quiescence search

Author: Alessandro Damiani

Date: 17:34:19 10/19/02

Go up one level in this thread


On October 19, 2002 at 20:08:49, Nagendra Singh Tomar wrote:

>Another question that is part of the same discussion is
>if(sval > alpha)
>{
>    if(sval >= beta)
>    {
>
>    }
>    alpha = sval; /* why this */
>}
>
>be setting alpha to sval we are telling the qsearcher that we will not be
>interested in any score less than the static score at the qsearch root.
>Why so?
>Normally we decide bounds on the search with a previous search done with a
>higher or same depth as the current search. But here we are deciding the bounds
>of a deeper search (qsearch) with a lesser depth search (static eval at the
>qsearch root).
>
>Any comments are highly welcome
>
>tomar
>

this is just maximizing. by using operator "max" one would write (pseudo
language):

   alpha:= alpha max value

as we know this is aquivalent to

   if alpha<value ->
      alpha:= value
   [] alpha>=value ->
      skip
   fi

or in C:

   if (value>alpha)
      alpha= value;


in the code you present maximazing and beta cut-off are just combined.

Alessandro



This page took 0.01 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.