Author: Vincent Diepeveen
Date: 09:47:55 10/11/02
Go up one level in this thread
On October 11, 2002 at 11:59:19, José Carlos wrote: >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. the simpler your evaluation is though, the easier it is to predict which branch is going to suit your evaluation better. >>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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