Author: José Carlos
Date: 12:10:42 08/04/04
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On August 04, 2004 at 14:52:45, Cesar Contreras wrote: >I'm having problems figuring out how to implement an SEE, i supose you need to >generate all moves to both sides, ordering on any way the captures, and >calculate the captures. Any info you can add will be apreciated. > >Thx You don't need to generate moves, only attacks to a given square. The idea of SEE (static exchange evaluator) is to predict the outcome of a capture sequence in a given square statically. So you want to know all pieces of both colors that attack that square. Then, your sort the pieces by increasing value (try to capture with small pieces first) and start simulating the captures, keeping track of the material. Consider this position: [D]rnbqkb1r/pp2pppp/2p2n2/3p4/4P3/2NP4/PPP2PPP/R1BQKBNR w KQkq - 0 4 You want to know the SEE of the two possible captures: 1. Nxd5: black can take with pawn, knight and queen, in this order. Black takes with pawn (you eliminate Pc6 from the list). Now you're at -2.00 (1.00-3.00). You can take with Pe4. exd4 and you're at -1.00; you can stop here because you know for sure you're gonna lose material with Nxd5 2. exd5: again cxd5, Nxd5 and Qxd5 for black. First cxd5. Eval=0. You still have one attacker, the knight: Nxd5 (+1.00). Black Nxd5 (-2.00) for you. You have no more attackers, so you review the capture list. You see you can sit after black's cxd5 with eval 0. So SEE value for exd5 is zero. This is the idea. The implementation is more fun if you figure out ;) José C.
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