Author: Komputer Korner
Date: 21:34:41 10/19/98
Go up one level in this thread
On October 15, 1998 at 19:56:31, Robert Hyatt wrote: >On October 15, 1998 at 14:08:24, ed wrote: > >>On October 15, 1998 at 10:12:45, Robert Hyatt wrote: >>>No it can't. Alpha/beta doesn't produce a score for *every* move searched. It >>>produces a score for the first (hopefully best) move and then only proves that >>>the score for every other move is lower, without determining how much lower. >> >>Yes, I do understand Alpha/Beta. Many a times, a pgm will have a tough time >>deciding/alternating between move A or B or C, and, and it is these move A and B >>and C that I want to see in the written analysis. Also, if the top 3 variations >>is displayed on the screen, it gotta be also possible to save to a file, won't >>you say? :) >> > >One point: repeat after me slowly: "there is no way for alpha/beta to produce >a best move, a second-best move and a third-best move, without tripling the >time it takes to complete the search..." > >There are approximations. IE you get the best move at ply=10, but then it is >replaced later by a better move at ply=10... you can show both PVs and say >they are the best two. Or you can save the ply=9 pvs too, but that is much >less accurate. > >Or you can do it the correct way: search all moves, save the best as "#1", >then remove that move from the move list, and search all the moves except that >one again. That gets #2. Repeat as often as you want, knowing that each >search will take about as long as the previous one, since the best move takes >90% of the total time... > > > >> >>>It takes a second search to get the real score/PV for a second-best move... >> >>Hmmm... now that u mention it, it does make sense. Bob why can't programs present the move list either in a log file or on screen in the alpha beta order? CSTAL does a 1 ply search to get the score evals for each legal move but unfortunately it doesn't list the moves in the alpha beta order of the engine search. Why couldn't a program do this? -- Komputer Korner
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