Author: Peter McKenzie
Date: 14:53:35 11/20/01
Go up one level in this thread
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. 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 )
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