Author: Dann Corbit
Date: 19:20:35 03/07/06
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On March 07, 2006 at 22:12:42, Nathan Thom wrote: >On March 07, 2006 at 21:34:10, Dann Corbit wrote: >> >>Opening books hold the frequently played positions near the origin. >>If we are talking about some position 50-60 plies down the road, the odds of >>hitting it during game play are "astronomical". No, they're "commical" -- and >>uneconomical. >> >>Just the bare positions -- ignoring half-move clock and 3-time repeat are 10 to >>the 50th power. So, let's suppose that our intrepid programmer analyzes one >>billion positions. The odds in hitting one of them are one in ten to the >>forty-first power. Not good. Plus you would have a bit of bloat storing the >>positions and a bit of time spent searching for them. >> >>Now, let's suppose that we bypass all these objections and say "What the heck, >>let's do it anyway!" >> >>Well, when we look at memory, we will see (one billion * hash element size) >>bytes of memory consumed. A very small hash entry would consume 16 bytes but >>we'll say he's clever and stores only 8 bytes. That would be 8 gigs of ram. >> >>"Well..." (you may retort) "perhaps they are loaded on demand." >> >>I suppose that a page fault for every new position would slow down the program >>so much that we would see 50-100 NPS at best. While Rybka may be a slow >>searcher (let's not start that debate) it's certainly not that slow. >> >>I suppose we're just going to have to admit that V.R. is a clever guy, and that >>he hasn't stored the middle game in the computer's data segments. > >What about only considering parts of the board (<64 squares) or only specific >pieces. e.g. only consider rooks+kings and have a pre-generated table of the >most common situations and best move? Sure, the other pieces which have been >ignored could make the move ridiculous or illegal but i wonder what kind of >success rate this would give? In the evaluation it would give good success. But that is what everyone does. As data statements it would have zero usefulness.
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