Author: José Carlos
Date: 08:59:19 10/11/02
Go up one level in this thread
On October 11, 2002 at 11:15:14, Vincent Diepeveen wrote: >On October 11, 2002 at 11:11:01, Jeremiah Penery wrote: > >>On October 11, 2002 at 10:46:16, Gian-Carlo Pascutto wrote: >> >>>On October 11, 2002 at 10:38:12, Jeremiah Penery wrote: >>> >>>>On October 11, 2002 at 08:09:59, Vincent Diepeveen wrote: >>>> >>>>>you skip one important point. Because of a simplistic evaluation >>>>>it was able to get 12.2 ply. If you use a more complex evaluation >>>>>then you do fullwidth not get 12.2 ply at all, but more like 10.5 ply. >>>> >>>>It did evaluation in hardware. The complexity of the function has NOTHING to do >>>>with the speed of computing it. This is obviously something you don't >>>>understand, or you wouldn't be writing crap like the above, or the below. >>> >>>You missed Vincents point. His point was that a more complicated >>>evaluation (with bigger positional scores) will slow down the search >>>compared to (for example) a piece-square evaluation, because it causes >>>more instability. >> >>Having a more complicated evaluation does not require having bigger positional >>scores, but I agree that in the general case that is what happens. However, >>search instability depends on the correctness of your evaluation function and >>your move ordering - the variability of the evaluation function is secondary. >>If your evaluation is very complex, but also extremely accurate, it will be far >>more stable than a simpler but less accurate evaluation will yield. > >If you always return 0 as score, then any move will give a cutoff. If your evaluation is good enough to always know what side is winning, it will be very stable. >If you are material based, just material, then capturing a piece will >give usually a cutoff. If you can evaluate tactical factors in eval, you'll try the best capture first, and give a cutoff. >If you have a complex evaluation, then you do not know in advance whether >trying a capture is going to give a cutoff. If your eval is good enough, you can. >Obviously it's harder to order moves too. Try a random eval. It will give a horrible branching factor. And it's pretty simple. It's not how _complex_, it's how _adequate_. You want an evaluation function that fit into your search so well to help it finding the best move as soon as possible. Period. >If you knew ahead which move would going to give a cutoff for you, >why the hell would you do a search anyway? If you know it 100% sure, you don't need the search. But 100% is not possible (at least, today). But the closer to the 100%, the better, of course. José C. >It's a trivial thing in algorithms. Already reported years ago by >the darkthought team (Peter Gillgasch). > >Best regards, >Vincent
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