Author: Uri Blass
Date: 12:55:01 06/18/01
Go up one level in this thread
On June 18, 2001 at 15:46:13, Bas Hamstra wrote: >On June 18, 2001 at 13:05:38, Robert Hyatt wrote: > >>On June 18, 2001 at 10:51:12, Bas Hamstra wrote: >> >>>On June 18, 2001 at 08:33:21, Ulrich Tuerke wrote: >>> >>>>On June 18, 2001 at 08:28:08, Bas Hamstra wrote: >>>> >>>>>On June 17, 2001 at 01:09:50, Robert Hyatt wrote: >>>>> >>>>>>On June 16, 2001 at 22:59:06, Vincent Diepeveen wrote: >>>>>> >>>>>>>Hello, >>>>>>> >>>>>>>From Gian-Carlo i received tonight a cool version of crafty 18.10, >>>>>>>namely a modified version of crafty. The modification was that it >>>>>>>is using a small sense of Singular extensions, using a 'moreland' >>>>>>>implementation. >>>>>>> >>>>>> >>>>>> >>>>>>Instead of modifying Crafty to simulate Deep Blue, why didn't you >>>>>>modify Netscape? Or anything else? I don't see _any_ point in >>>>>>taking a very fishy version of crafty and trying to conclude _anything_ >>>>>>about deep blue from it... >>>>>> >>>>>>Unless you are into counting chickens to forecast weather, or something >>>>>>else... >>>>> >>>>>I don't agree here. It is fun. Maybe not extremely accurate, but it says >>>>>*something* about the efficiency of their search, which I believe is horrible. I >>>>>think using SE and not nullmove is *inefficient* as compared to nullmove. We >>>>>don't need 100.0000% accurate data when it's obviously an order of magnitude >>>>>more inefficient. >>>> >>>>May be you are right, if the program is running on a PC. However if you can >>>>reach a huge depth anyway because of hardware, may be you can afford to use >>>>this, because it doesn't matter too much wasting one ply depth ? >>> >>>I don't see why inefficiency becomes less of a problem at higher depths. >>>Nullmove pruning reduces your effective branching factor to 2,5 where brute >>>force gets 4,5. So you could suspect at higher depths the difference in search >>>depths grows, starting with 2 ply, up till how much, 5 ply? >> >>Several things here. First a normal alpha/beta program does _not_ have a >>branching factor of 4.5... it is roughly sqrt(n_root_moves) which is closer >>to 6. > >Not at all. Have you never tried Crafty without nullmove? See below my engine >output, rootposition. Where is the 6? I have never had 6, in my opinion 4,5 on >average is normal. I think that the initial position is relatively simple so the branching factor is lower in this position. Hash tables can also help for the branching factor at small depthes but I doubt if they help much at big depthes. Uri
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