Author: Tony Werten
Date: 07:55:57 11/29/01
Go up one level in this thread
On November 29, 2001 at 06:27:43, James Swafford wrote: >On November 29, 2001 at 01:10:25, Tony Werten wrote: > >>On November 28, 2001 at 20:16:45, James Swafford wrote: >> >>>On November 28, 2001 at 13:41:26, Tony Werten wrote: >>> >>>>On November 28, 2001 at 13:05:23, Derek Mauro wrote: >>>> >>>>>When I call search(), I'm supposed to be using -INFINITY as alpha and INFINITY >>>>>as beta. Anyway, I've never used INFINITY in a program before. How do I use >>>>>INFINIITY? Do I need to include a special library or just define it as the >>>>>largest possible int value, or something else? >>>> >>>>Just use the value you use for checkmate (without depth correction ) That's >>>>infinite enough. >>>> >>>>Tony >>> >>>The absolute value for INFINITY for me is a little bigger than >>>CHECKMATE, so that the condition if (score > alpha) is true >>>even when the first move gets a score -CHECKMATE and alpha is >>>-INFINITY. Nothing gets backed up to the pv unless that condition >>>is met. (Of course you're in serious trouble in that case. :) >> >>You're already in trouble if a move scores -checkmate. If it happens at ply 0 >>than the game is finished, if it is ply 1 or more the score should be >>-checkmate+1 (or more ) > >That's true, assuming he will use depth correction. (I do.) >The point is to ensure the first move will get placed in the pv. >If the range of valid scores is in the closed interval [-CM .. CM], >why make assumptions when it's easier to move INFINITY outside >that range? True, but I got into the strange habit lately to do this anyway. The idea is that if I think it shouldn't break anything, and I give it the chance there are 2 possibilities. Either it doesn't break anything or I should rethink. It does seem to chance the small bugs into big ones, wich are easier to find. > >A silly argument to be sure... Yes, but then again, life tends to be rather silly. (with a few exceptions) Tony > >-- >James > > > > > > >> >>Tony >> >>> >>> >>>-- >>>James
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