Author: Tom Kerrigan
Date: 10:54:03 03/23/00
Go up one level in this thread
On March 23, 2000 at 13:49:59, Andrew Dados wrote: >On March 23, 2000 at 13:37:02, Tom Kerrigan wrote: > >>On March 23, 2000 at 13:18:52, Andrew Dados wrote: >> >>>On March 23, 2000 at 13:08:51, John Coffey wrote: >>> >>>>Does interative deepening insure that a program will pick the fastest >>>>improvement? I.e. if a program can improve its position by .1 pawn in 3 moves, >>>>how do I know that it won't choose a .1 improvement in 5 moves instead? >>>> >>>>John Coffey >>> >>> Any brute-force search (including alpha-beta) guarantees it by definition :) >> >>I don't think so. The brute force searches that people do in computer chess rely >>on evaluation functions that do not distinguish between depths. >> >>-Tom > >The question as I understood was: When there is an improvement within e.g. 3 >plies, can we be sure that our search won't miss it (searching 3 plies deep). >And _that_ we can be sure. > >two remarks: >1) null move pruning <> brute-force search. >2) 'improvement' is defined by program solely: evaluation function, qsearch and >all horizon effects, not by us. That's not the way I read the question. "if a program can improve its position by .1 pawn in 3 moves, how do I know that it won't choose a .1 improvement in 5 moves instead?" This doesn't imply that the program missed anything at either depth. And if a program is searching 5 moves deep, then it will always choose the move that improves the position _after_ 5 moves. Whether or not this also improves its position after 3 moves is up for grabs. -Tom
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