Author: Dann Corbit
Date: 16:05:09 04/01/04
Go up one level in this thread
On April 01, 2004 at 18:38:59, Sune Fischer wrote: >On April 01, 2004 at 18:29:27, Dann Corbit wrote: > >>On April 01, 2004 at 17:59:38, Eugene Nalimov wrote: >> >>>On April 01, 2004 at 15:16:34, Marc Bourzutschky wrote: >>> >>>>The Chessmaster format is indeed better >>> >>>What does it mean "better"? :-) >>> >>>It stores less information, thus compresses better. >> >>I have an idea that I think would be helpful if you should be so kind as to >>perform it. >> >>Write a scanner that reads your wonderful EGTB files and spits out a two bit >>state only for each position (won/lost/drawn/broke) to create bitbase files. >> >>The reason I suggest it is that a bazillion programmers won't have to reinvent >>the wheel. >> >>I suggest the use of the bitbase files early in the search (completely pulled >>into ram) and then EGTB at the leaves if the bitbase indicates it is worthwhile. > >You must mean it the opposite way, bitbases at the leaves and EGTBs a near root? > >I think it would be better to use bitbases in the entire search and only use >full EGTBs when the position is at the root. > >Or, if you want the search to eventually return mate scores, probe EGTBs when >bitbases say it is won and beta>=mate_bound or bitbases says it lost and >alpha<=-mate_bound. >Perhaps probing directly into EGTBs when window allows it would be faster, >matter of tuning of course. I guess I had not thought about it carefully enough. I imagined using bitbases to get a won/lost/drawn opinion (at all nodes). But unless you know the exact value of the leaves, I don't see how you can choose the best move. I imagined something like this: If the best evaluation is drawn or lost, who cares. Do whatever move is among the suggested list. If the best evaluation is won, then: Examine the bottom leaves that are won and perk the correct values back up. How will we otherwise find the true value? I am afraid I don't understand how it can work.
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