Author: James Swafford
Date: 18:46:07 11/21/00
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On November 21, 2000 at 10:23:04, Brian Richardson wrote: >On November 21, 2000 at 09:00:16, Rafael Andrist wrote: > >>Normally, quiescence search is used at the end of a tree. It seems to me, that >>it makes only sense to do qsearch after the last increment. But if there is a >>time limit and after the last increment is no time to do a qsearch (or you must >>stop in the middle of the search), the program can have a completly wrong >>evaluation. How is this handled in chess programs? >> >>Rafael B. Andrist > >Most programs use iterative deepening, so the principal variation (and a best >move so far) is always known from the prior (last) completed iteration. If the >qsearch or the "full width" search does not complete before a time limit I think >the results of that incomplete iteration are generally discarded. For example, >the search (and qsearch of each leaf node) finishes for iteration at depth n. >Depth n+1 does not finish. The best move from the depth n search is used. I don't think you need to complete the iteration, just the move. Let's say at iteration n your best move was m1. During iteration n+1, move m1 is the first root moved searched and gets a score. Then m2 is searched (and is finished) and gets a score s2. Let's say the time expires while searching m3 and you abort the search - so only two moves were completely searched in iteration n+1. If s2 > s1, I'd say choose move 2. Maybe that's what you meant; I'm not sure. :-) -- James
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