Author: Andrew Williams
Date: 02:24:24 11/20/01
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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 That's exactly how it is done. On entry to your quiesce() function, do an evaluation and store the result. If the result is >= beta, you can return beta as your result immediately (it's a great position from whoseTurn's point of view so there's no need to do more work). Otherwise, try the captures. If none of them gives a score greater than the stored evaluation you did at the top, return that because you assume that there is at least one non-capturing move that is "neutral". Andrew
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