Author: Tord Romstad
Date: 11:24:55 01/08/04
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On January 08, 2004 at 11:47:46, Andreas Herrmann wrote: >On January 08, 2004 at 09:37:59, Tord Romstad wrote: > >>On January 08, 2004 at 08:39:24, Andreas Herrmann wrote: >> >>>in my engine, mobility is one of the most powerful parts in the eval. I >>>calculate it from my attack tables. >> >>One of the nice things you get almost for free with attack tables is that it >>is almost trivial to compute safe mobility rather than pseudo-legal mobility. >> >>>Calculating attack tables is very slow, but you can use them for a lot other >>>things. >> >>How slow is the attack table calculation for you? Do you have a couple of >>test positions we could compare? In the opening position (which is probably >>not a good position, because all sliding pieces are blocked) I generate my >>16-bit attack tables almost exactly 1000,000 times per second on a PIV 2.4 GHz. >> >>Tord > >it's very slow in my engine, it costs me in the most cases about 1 ply. But my >current attack tables, are not very good. I'm generating and using the attack >tables at the moment only in the opening and middle game, but not in the >endgame. I calculate them in all phases of the game. It is possible that I could do without them in the endgame, but I don't think it would buy me much. They are very quick to calculate when there are few pieces left on the board. >And i calculate only the number of attackers per side and the total attacking >piece value per side, while scanning my piece lists. With my current data, i >can't do for excample SEE in qsearch, or calculate hanging pieces and some other >stuff. So that was the reason for my question to Ed in my other posting, because >i'm looking for another better solution to do SEE and some other things. I see. >Your generating speed with 1 million per second seems realy fast. I don't think it is. Unfortunately I don't have many other data points, but if I recall correctly Rebel searches more than 1 million nodes per second in a typical middle game, and of course it does much more than just computing attack tables at every node. My guess is that my generating speed is well below average. Tord
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