Author: Daniel Clausen
Date: 02:32:07 05/13/02
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On May 13, 2002 at 00:22:28, Russell Reagan wrote: >If I have one legal move array, will that work for searching recursively? For >example, in AlphaBeta() where it says GenerateLegalMoves(), if I have a global >variable that won't work, at least it doesn't seem like it would, because you >would be writing over the moves from previous plys. So it would seem like you >would need a local variable for this. But in TSCP it looks like Tom used a >global legal move list in gen_dat[] but he also has a first_move[] array that >could do something to make this work. I think I get the general idea, but I'm >not very clear on it. > >It seems like a simpler solution would be to use a local variable inside >AlphaBeta() to store the legal moves, then they would be saved on the stack >during recursive calls. Is there any downside to this method? I'm not quite sure why people use the approach of using a global array and a first_move[] array really. Basically it's a stack. Since there already is a stack, I prefer to use this one rather than implementing my own. Note that allocating space on the stack doesn't really cost anything, as long you don't initialize the array each time. (luckily C doesn't do this by default with local variables) I guess you can gain some NPS with the global array approach, but IMHO it's not worth it. YMMV, as always. Similarly I don't see why people use this triangle array for the PVs. I prefer the straightforward solution as Bruce also explains on his excellent web page (http://www.seanet.com/~brucemo/topics/pv.htm) It's crystal clear, doesn't give me any headaches and is maybe a few NPS slower. So what. Sargon
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