Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: a question for programmers about the search depth

Author: Robert Hyatt

Date: 16:03:00 12/24/98

Go up one level in this thread


On December 24, 1998 at 11:02:09, blass uri wrote:

>
>On December 24, 1998 at 10:52:40, blass uri wrote:
>
>>
>>Suppose you do a brute force search to depth x then what is the longest lines
>>that you may search?
>
>I mean seeing everything for x plies when I say depth x.
>
>Uri
>
>
>
>
>
>>
>>I understood that for Junior the longest line is at most 4x and  for crafty the
>>longest line is at most 2x.
>>
>>correct me if I am wrong
>>
>>What is the longest line for other engines

first you have to have a common "depth" term.  The depth junior displays is
_not_ the same depth the rest of us display, so you can't compare that.

But in the case of Crafty, the nominal depth of search has nothing to do with
the number of moves in the PV.  IE with a 10 ply search I can hit ply=50 at
times if the extensions get triggered just right.  Someone posted a position
months ago that was a mate in 30, that Crafty found with a fairly shallow
(10 plies or so) search, yet it went a full 60 plies deep.  This position was
one of the "rebel" positions where there was a contest to construct the deepest
mate with the fewest nodes...

But when you see 10 plies, you do know that the pv was searched to at least 10
plies, but could possibly have went to 50 plies (or more) along some variations.
Also you know that other non-PV moves may well have not even been searched to
10 plies thanks to the null-move...




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.