Author: Alessandro Scotti
Date: 08:43:16 08/24/04
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On August 24, 2004 at 11:32:28, Tord Romstad wrote: >On August 24, 2004 at 10:56:13, Alessandro Scotti wrote: > >>On August 24, 2004 at 10:50:07, Álvaro Begué wrote: >> >>>>I tracked the cause to the quiescence search returning mate, where it doesn't >>>>actually explore all the possible variations. >>>Your diagnostic is incorrect. There is no problem with returning mate scores in >>>the quiescence search. You must be doing something else wrong. >> >>If I evaluate a position using the quiescence search and that returns "mate in >>5", how can I be sure that it's really a mate in 5 if the quiescence search >>hasn't explored all the possible moves? > >It sounds like you have forgotten to allow the return of "stand pat" scores >in the qsearch, or something similar. If you are at a qsearch node where the >side to move is not in check, and all the moves you search are refuted by a >mate, you shouldn't return the mate score, but the stand pat score. The only >way the qsearch can possibly return a mate score is if the side to move at >the first ply of the qsearch is in check, and all legal check evasions are >refuted by a mate. And in this case, of course, you *can* be sure that it's >really a mate in x moves. Tord, I think this explanation and the magic words "stand pat" have rung a bell in my head... :-) Can't check the code right now but I think you put me on the right track... thanks!
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