Author: Pham Minh Tri
Date: 22:26:16 10/24/00
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On October 24, 2000 at 22:40:12, Robert Hyatt wrote: >On October 24, 2000 at 20:01:31, Pham Minh Tri wrote: > >>Hi, >> >>In the book "Scalable Search in Computer Chess" you listed the move-ordering >>scheme as following: >>1. hashed move >>2. good capture moves >>3. killer moves >>4. history moves, >>5. statically pre-sorted remaining moves >>6. bad capture moves. >> >>My question are: >>1. How about pv move? Do you install them into hash table? If yes, what is >>benefit (I think if we keep separating pv and hashed moves, we will have more >>good moves for searching first). > >I'm not Ernst, but think about your question. Why would the hash table have >a "best move" that is _not_ the PV move? The only problem is that the hash >table won't have a best move for every ply, because every other ply doesn't >have a "best move" at all in the context of alpha/beta. The fix (for me) is >to simply "stuff" the PV into the hash table at the start of each iteration. Thank alot for your answer. Actually, I learnt how to stuff the PV moves into hash table from your Crafty. I was wordering why you do not retrieve pv move from pv table and use the best move from hash table as the second best move (it may improve a little move ordering)? >>2. How do you divide good and bad capture moves? Are the bad capture moves >>really "bad" therefore you listed them in the end (I mean they would be higher >>order)? >>3. Could you explain more details about statically pre-sorted remaining moves? >>Thank you in advance, >>Pham > > >Ernst uses MVV/LVA, which means the first capture he tries is the most valuable >piece that is being attacked by any of his pieces, and then he tries the least >valuable attacker for that piece. Others of us use SEE (static exchange >evaluator) which is a bit more accurate, but costs a bit more computationally.
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