Author: Serge Desmarais
Date: 16:39:38 09/27/98
Go up one level in this thread
On September 21, 1998 at 18:23:50, Robert Hyatt wrote: >On September 21, 1998 at 15:13:41, John Coffey wrote: > >>On September 21, 1998 at 14:58:33, John Coffey wrote: >> >>>If on the otherhand I search the first move that wins a piece, and all but one >>>of my opponents responses regains material, then I could do a null move after >>>all but one of my opponent's responses, thus saving close to 80 or 90%. Maybe >>>this is the piece of the puzzle that I am missing? >>> >>>Thanks for the response. Best wishes, >>> >>>John Coffey >> >>Errr... maybe not. If all but one of my opponents moves fail to regain a piece >>then doing a null move will effectively gives the other side two moves in a row >>and then they can regain the piece anyway, thus defeating the null move. So >>the null move must work when the opponent has no threats at all. It is hard >>for me to see this happening often enough to get such a dramatic *exponential* >>reduction in the tree size. >> >>Again I will take your word for it. I am assuming that we only try the >>null move when we have gained material? This is what I have read, but maybe >>you try null moves at other times? If so then this would make more sense >>to me. >> >>John Coffey > > >I try them _everywhere_ in the search, before trying any other move. The idea >is that if your opponent can't take two moves in a row and crush you, your >position is overwhelming and doesn't need any further searching to prove that >it is probably winning... But what if it is a quiet and blocked position with both sides moving behind their respective lines and with most pieces on the first rank at one time or another? Then, even giving 1 or 2 free shots to your opponent, he would not be able to really hurt you seriously in anyway, except by moving a pawn and breaking open a line, at worst winning a pawn? Serge Desmarais
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.