Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: DB will never play with REBEL, they simple are afraid no to do well

Author: Ratko V Tomic

Date: 13:14:06 10/15/99

Go up one level in this thread


>>Roughly
>>estimating, there are perhaps 3-4 non-junk moves in a typical middlegame
>>position and the effective branching factor may be 6-8 in such position.
>
>I've never seen such a high branching factor in any sort of typical position.
>3-4 (even sometimes 2) is a much more typical branching factor for today's
>programs.
>

The best you can do with the full width search (I was not counting extensions
here, which are highly selective) is the square root of the number of legal
moves, which in a middle game would be typically 35-45 or so, giving thus B as
stated earlier. With some form of forward prunning, you can do better, of
course. Do you have some branching factor figures for the stronger among the
selective search programs?

In any case, as long as the effective branching factor is greater than the
average number of non-junk moves per node, the percentage of non-junk nodes
examined goes exponentially to zero as depth increases. While I have put above
3-4 as non-junk moves, that may be a bit generous as well. Experiment, along the
lines suggested earlier, would probably answer this question reasonably
accurately.




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.