Author: Sune Fischer
Date: 05:22:15 12/20/02
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On December 20, 2002 at 08:00:31, Gerd Isenberg wrote: >>The overhead of making/unmaking pinned pieces is extremely small. >>I count about 0.5-1.5% pinns, the make/unmake move rutines take maybe 20% (in my >>case) but I only need to do half a move to see if the move is legal, in total >>that's about 0.075% overhead because of illegal pinned moves!! >> >>I'm pretty sure there is _no way_ you can detect pinns faster and improve on >>this overhead. > >Hi Sune, > >I'm not sure, specially if we consider hammer or SSE2. I use dumb6fill for 2 or >3 directions simultaniously (8 mmx-registers). With SSE2 or hammer it can be >done for all 8-directions in parallel, with sliders and king in one 128-bit-xmm >register. A lot of work to save 0.1%, at best :) >>I agree, there are other reasons to do it. It must be good for extensions, as >>Uri says a pinned queen might be reason to extend. >> >>One of the best things though, must be if you generate all moves all the time, >>that would be real nice for extensions and threat detections. >> >>But I didn't think any bitboarders generated all moves since bitboards are so >>good at incremental generation, is this what you do? >> >>-S. > >I guess yes, but incremental generation is possibly the wrong term. I don't look >to previously generated moves two plies before. It's a finite state machine move >generator, trying to generate as less as possible, hoping for a cutoff. Yes, that's what I figured :) > But my >final approach with hammer in mind is quite unclear so far. The question is, how much do you need those extensions? I also like the full knowledge idea, but on the other hand if you slow down the program 100% just to produce a good extension here and there, it might be better just to run brute force faster and get the extension simply because you go that extra ply. When going an extra ply you also see a lot of other stuff of course. -S. >Gerd
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