Computer Chess Club Archives


Search

Terms

Messages

Subject: Null move question

Author: Pallav Nawani

Date: 11:05:30 05/12/04


Hello,

I am trying to implement NULL move heuristic in my chess program, Natwarlal.
Addition of null move reduces the number of nodes drastically, but it leads to
the program making stupid captures. For instance, capturing a pawn by a bishop
when the  pawn is well defended. What should I do to avoid this problem?

The code I use follows:
(gi is the structure used to hold moves, undo stack, etc.)

  // Lets try a NULL move
   if(!avoidnull
	 && !gi.uptr->incheck
	 && gi.ply > 1) {

      make_null_move(gi);
      if(depth - NULLRED  > 0)
	 score = -search(gi, -beta, -alpha, depth - NULLRED);
      else
	 score = -qsearch(gi, -beta, -alpha);
      undo_null_move(gi);
      if(score >= beta) {
	    return beta;
      }
   }

Thanks in advance.
Pallav Nawani



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.