Author: James Swafford
Date: 14:57:35 11/20/01
Go up one level in this thread
On November 20, 2001 at 17:53:35, Peter McKenzie wrote: >On November 20, 2001 at 16:55:13, Michel Langeveld wrote: > >>On November 20, 2001 at 05:04:42, Michel Langeveld wrote: >> >>>Hello all, >>> >>>I implemented qsearch in my program nullmover, but got a problem for it back. >>> >>>When I search with a depth 1 (just testing at the moment) my program thinks that >>>after the openingmove 1. d4, ... h6! is the best move. >>> >>>After h6 the qsearch starts. >>> >>>[D]rnbqkbnr/ppppppp1/7p/8/3P4/8/PPP1PPPP/RNBQKBNR w KQkq - 0 2 >>> >>>The qsearch evaluates _only_ captures now. The program thinks white HAS to take >>>on h6 then (is only capture in that position) and black can win a bishop after >>>gxh6 or Rxh6. So score is about +2 for black then. This is incorrect of >>>course.... >>> >>>I'm thinking about ways to solve this. One way is to implement a null move so >>>that beside capturing there's always a doing nothing option. But I was curious >>>how you guys solve this thing. >>> >>>Regards, >>> >>>Michel Langeveld >> >>Ok, >> >>Fixed the qsearch with a no move situation >>Debugged it and tested it. It works very well at the moment. >> >>I also implemented a better move ordening. >>My search sometimes BOOMS already at ply 1 in tactical positions. >>How can I fix this? Can I stop qsearch at an centain depth? > >You can, but its not recommended. You shouldn't need too. > Are you sure? I'm sure it doesn't happen very often, but it seems naive to let the recursive call go and go and go... You've got me curious. I'm going to put in a counter and see how often that happens. -- James >I guess you either have a bug or your move ordering is broken. Are you >searching captures only? Or you ordering using MVV/LVA ? > >> >>history: >>(d2-d4 e7-e6 c1-e3 f8-d6 d4-d5 e8-f8 e3xa7 d6xh2 a7xb8 h2xg1 h1xh7 > >d6xh2 indicates you aren't using MVV/LVA >Always capture the Most Valuable Victim (MVV) first! a8xa7 should be searched >before d6xh2. a8xa7 will cause a quick fail high, therefore d6xh2 will never >need to be searched at all. > >> a8xa2 b8xc7 g1xf2 e1xf2 d8xc7 d5xe6 a2xb2 e6xf7 h8xh7 f7xg8B b2xb1 >> d1xb1 f8xg8 b1xb7 c7xc2 b7xd7 c2xe2 f1xe2 c8xd7 )
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.