Author: Ingo Lindam
Date: 07:50:47 12/05/02
Hello all, quoting myself I would like to start a new discussion about why I think its worth two obtain N-best-trees (as a result of the search process), containing the N-best moves in each exactly evaluated node of the search tree. Robert Hyatt agreed that the effort to do this should be able to estimate by getting N*N times slower. This means 4 times slower to obtain a 2-best-tree instead of just obtaining a single PV: Ofcourse I am aware of winning nothing and just loosing a lot of time when I play games and my aim is just to obtain the best move according to one given evaluation function (at the end of the quote I hint on the possibility to use the N-best-tree for rescoring on basis of a second, improved evaluation function that is more complex and therefor just usable on a reduced search space/tree). " BUT... I think engines can do more than this (if we allow them to do so). They can analyse and give a tree to argue for their decission by giving a scored tree, rather than a single variation. And also the developer will save so much time (yes, SAVE time) by doing this (not when playing a game) but when testing and developing. Give the engine a lot of time to analyse some crucial/test positions, store the tree and than enjoy the speedup when testing several evaluation methods on this reduced search tree. And when you agree that doing a N-best search slows down not exponentially, but going deeper into the searchtree does. Then there must be a certain limit for going deeper. And when you have no time to go deeper, why not use a better, more complex evaluation function on the N-best tree in that time. Even more when you think of... a) N is const.!: so = O(N*N * x^ply) = O(c * x^ply) keeps O(x^ply) in O(ply) notation b) rescoring on the N-best tree can given without any problems to another processor or even maschine. c) even generating the N+1-best-tree given a N-best-tree can done by an additional maschine for ply K as soon as N-best tree for play K. d) generation the N+1-best-tree (i the MP case) can be accellerated by giving the hash of generating the N-best tree. Do I miss something?" Internette Gruesse, Ingo
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