Author: Vikrant Malvankar
Date: 19:54:09 03/07/06
Go up one level in this thread
On March 07, 2006 at 22:20:35, Dann Corbit wrote: >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. Are current Engines using differant evaluation techniques based on the move no. and pieces remaining on the board?
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