Author: José Carlos
Date: 05:52:03 11/20/01
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On November 20, 2001 at 05:24:24, Andrew Williams 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 > >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). Then, if the static eval is > Alpha, do Alpha = eval, which will save some nodes. José C. >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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