Improvement and Estimate of MTD-f.

Accession number;03A0679577
Title;Improvement and Estimate of MTD-f.
Author; SHIBAHARA KAZUTOMO (Tokyo Univ. of Agric. and Technol.) INUI NOBUO (Tokyo Univ. of Agric. and Technol.) KOTANI YOSHIYUKI (Tokyo Univ. of Agric. and Technol.)
Journal Title;Joho Shori Gakkai Kenkyu Hokoku
Journal Code:Z0031B
ISSN:0919-6072
VOL.2003;NO.79(GI-10);PAGE.1-8(2003)
Figure&Table&Reference;FIG.3, TBL.3, REF.4
Pub. Country;Japan
Language;Japanese
Abstract;The best-first search is an ideal algorithm but is practically difficult to use because of the problem of strage. MTD is an advanced best-first search which explores a game-tree in a depth-first manner. MTD uses a NULL-window search at a root node in several times and is able to find a solution with less number of search node than an alpha-beta search. Previous researches reported that MTD-f, which uses an approximate minimax value at first for the NULL-window search, showed the best results. We show the nature of MTD-f for random-game trees in this paper. From this observation, we propose several methods for the improvement and analyze these performances. These method are concerned how to determine initial values of NULL-windows. As a consequence, MTD-f with MTD-step, called MTD-f-step, and MTD-f-alpha-beta can find solutions 3 percent faster than MTD-f in our experiments. (author abst.)