Author: Robert Hyatt
Date: 16:55:58 03/24/99
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On March 24, 1999 at 12:26:16, Bruce Moreland wrote: > >On March 24, 1999 at 08:45:23, Robert Hyatt wrote: > >>Quiesce is a simple search that looks like this (details omitted but basic >>idea is present): >> >> int Quiesce(alpha,beta,wtm) { >> alpha=Evaluate(etc); >> if (alpha > beta) return(beta); > >You mean alpha >= beta, but this is goofy if Evaluate returns a value < alpha, >isn't it? This will make your window wider. > >bruce > yes... I just tried to make the code short. it really looks like this: value=Evaluate(); if (value > alpha) { if (value > beta) return(beta); alpha=value; } etc... Bob >> while(more_captures) { >> MakeNextCapture(); >> value=-Quiesce(-beta,-alpha,wtm^1); >> if (value > alpha) { >> if (value >= beta) return(beta); >> alpha=value; >> } >> } >> return(alpha); >> } >> >> >>the difference between Quiesce and Search is that Quiesce sets the lower bound >>to the current positional evaluation + material. Because we allow the current >>side to 'stand pat' and not play any move (capture only) if he doesn't want to. >> >>Search() doesn't allow one side to 'not move' as that is illegal. But here we >>use it to 'stop' the sequence of captures and exit, or else we can make a >>capture that helps our score, but then the opponent gets to decide whether he >>wants to 'stand pat' or make a capture in response. >> >>Hope that helps.. >> >>If something isn't clear, feel free to ask, as there could easily be a typo in >>the above...
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