Incremental Beam search

  • Authors:

  • S. G. Vadlamudi;Sandip Aine;P. P. Chakrabarti

  • Affiliations:

  • Department of Computer Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, WB 721302, India;Indraprastha Institute of Information Technology, New Delhi, DL 110020, India;Department of Computer Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, WB 721302, India

  • Venue:
  • Information Processing Letters
  • Year:
  • 2013

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Abstract

Beam search is a heuristic search algorithm that explores a state-space graph by expanding w most promising nodes at each level (depth) of the graph, where w is called the beam-width which is taken as input from the user. The quality of the solution produced by beam search does not always monotonically improve with the increase in beam-width making it difficult to choose an appropriate beam-width for effective use. We present an algorithm called Incremental Beam Search (IncB) which guarantees monotonicity, and is also anytime in nature. Experimental results on the sliding-tile puzzle, the traveling salesman, and the single-machine scheduling problems show that IncB significantly outperforms basic monotonic methods such as iterative widening beam search as well as some of the state-of-the-art anytime heuristic search algorithms in terms of the quality of the solution produced at the end as well as the anytime performance.