Author: James Swafford
Date: 09:21:56 01/29/02
Go up one level in this thread
On January 29, 2002 at 09:53:21, Robert Hyatt wrote: >On January 28, 2002 at 23:20:45, James Swafford wrote: > >> >>Does anybody do this? I just implemented a passed pawn extension >>that extends the depth by 1 if the move was a pawn move to the >>sixth or seventh rank, and that pawn is not blocked by a pawn of >>the opposite color. >> >>The results are pretty disappointing. It really blew up my search. >>I decided to modify the implementation by saying only looking for >>pawn pushes to the seventh rank, and it still can blow up pretty >>bad. >> >>Obviously most over the board positions would not trigger this >>extension, but there are some that would blow up the search like >>mad. >> >>One thought I had is to use a fractional extension scheme. That >>may help, but I'd like to know if anybody else does this extension, >>and what mechanisms they have in place to keep the search bloat >>under control. >> >>It's interesting to note that Bruce lists five different extensions >>on his (excellent) web page; he hasn't actually written about any of >>them yet, but passed pawn isn't even listed. Hmm... >> >>Any ideas or comments? >> >>-- >>James > > >I extend 3/4 ply when a passer reaches the 7th. But that only happens on the >ply where it is pushed to the 7th... I knew you did fractional ply extensions from some time back. How do you deal with the fraction once all extensions have been added up? For example, if you end up with extensions totalling 1.75 ply, do you truncate or round?
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.