Author: scott farrell
Date: 09:57:10 06/18/03
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On June 16, 2003 at 16:34:09, Andrea Griffini wrote: I had a routine that I used for ETC, that did doMoveUpdateKeysOnly - so it was a quicker make/unmake move, just for ETC. I eventually got rid of the whole lot though, I didnt get enough pay back, YMMV. Scott >I'm writing a chess program (iigchess on FICS) and I implemented >something I've seen described and to which I didn't think myself >before, that is doing a scan on all moves when entering a node >in the alpha-beta search to see if any of the reachable positions >is already in the hash table and its value can justify a beta cut. >Doing this after the hash table probe for this node but before >doing the move sorting and before starting evaluating the moves >seemed to me a possibility to save something, but after implementing >it I saw that I was actually getting an *increased* number of >visited nodes to reach the same search depth. > >Does this means there's a bug in my code or that can indeed happen ? > >My hash table is just a single-probe always-update one, but I >suppose that shouldn't be the problem. Also a position in the hash >table is considered usable only if the search depth that generated >the stored result is not lower than current search depth or if we >are in capture search (search depth is expressed in units of one >tenth of a ply, depth<0 means capture search). > >Andrea
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