Author: Tony Werten
Date: 01:36:53 08/08/01
Go up one level in this thread
On August 08, 2001 at 04:27:51, Alvaro Jose Povoa Cardoso wrote: >On August 07, 2001 at 23:08:14, Robert Hyatt wrote: > >>On August 07, 2001 at 16:42:27, Alvaro Jose Povoa Cardoso wrote: >> >>>Do you still have the ETC version of Crafty? >> >> >>No. But here is what you need: >> >>1. A function that will compute a updated hash key given a specific move. >>This is needed to avoid the MakeMove() overhead that will arise when running >>thru the move list to find if any of the resulting positions are hash hits. >> >>2. A simple ordering function that takes the move list, makes them one at a >>time, and probes the hash table to see if you get a hit and that hit will be >>an exact score that causes a cutoff, or if it will directly cause a cutoff. >>If so, that is the move you try first at this ply. >> > >I thought I could return immediately! You should be able to but there are some complicated matters wich are easiest solved by just making the move. (fe your repetition code.) cheers, Tony > > > > >>>If not could you post the ETC code/pseudocode, if that is not asking too much? >>>I know the net result of implementing ETC is null, but I think my program >>>(checkers) could benefit more than chess programs from ETC (at least I would >>>like to test). >>>I'm confused with ETC. Taking Crafty as the example, should we use HashProbe() >>>with ETC or should we make a special version of HashProbe() that does not >>>changes alpha and beta since all we want is the hash score? >>>Correct me if I'm wrong: >>>When using ETC, after making each move we should probe the hash table for the >>>opposite side right? >> >> >>Yes, as you are effectively "making" a move. >> >> >> >>>So instead of >>> HashProbe(tree,ply,depth,wtm,&alpha,&beta,&mate_threat) >>>we should do >>> HashProbe(tree,ply,depth,ChangeSide(wtm),&alpha,&beta,&mate_threat) >>> >>>Cutoffs should be done if the hash score >= BETA right? >>>When probing the hash table for ETCs should we consider >>>Upperbounds/Lowerbounds/Exactscores or >>>sould we simply use the hash score? >>> >>> >>>Thank you, >>>Alvaro Cardoso
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