Author: Jeremiah Penery
Date: 01:12:38 01/28/00
Go up one level in this thread
On January 28, 2000 at 01:35:20, Dave Gomboc wrote: >On January 27, 2000 at 21:20:46, Christophe Theron wrote: > >>On January 27, 2000 at 14:21:19, Dave Gomboc wrote: >> >>>On January 27, 2000 at 13:00:39, Christophe Theron wrote: >>> >>>>On January 27, 2000 at 00:06:19, Dave Gomboc wrote: >>>> >>>>>On January 25, 2000 at 21:26:19, Christophe Theron wrote: >>>>> >>>>>>On January 25, 2000 at 13:33:36, Dave Gomboc wrote: >>>>>> >>>>>>>It seems weird to me that when Ed Schroder says Rebel does better without >>>>>>>null-move than with it, people believe it, but people criticize the DB team for >>>>>>>not using it (e.g. from your text above: "by not using a good, known pruning >>>>>>>system..."). >>>>>> >>>>>>If the DB team did not have enough time, they could simply take the null move >>>>>>algorithm because there is documentation available on it. >>>>>> >>>>>>However null move is not the final say. Rebel does very well with ANOTHER >>>>>>pruning system. Junior does very well with ANOTHER pruning system as well. And >>>>>>there are other programs that do fine without null move, one of which I know >>>>>>very well. >>>>> >>>>>Yes, and DB does very well with ANOTHER pruning system too. What's your point? >>>>> >>>>>Dave >>>> >>>> >>>>My point is that they claimed that they did not use one. Several of us, looking >>>>at the apparent branching factor shown in the DB log files, have doubts about >>>>this. >>>> >>>> >>>> Christophe >>> >>>Where did they claim that they did not use one? In their published work they >>>clearly stated the contrary. >>> >>>Dave >> >> >>What did they say? >> >> >> Christophe > >Argh, I can't find the paper! > >In the software, there are some full-width plies, then some selective plies. In >the hardware, there are some full-width plies again. > >That is from memory though. > >Maybe Ernst can pull out his copy of Search Control in Deep Blue? I think the 'selective plies' are the extensions. The full-width plies at the end of the search, in hardware, coincide more with the evaluation function than anything. Rather than doing a static evaluation at the end of the search, they did that evaluation based on a 4-ply search done in hardware, to lessen any error involved.
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