A fixed-parameter tractable algorithm for combinatorial filter reduction

Fuente: arXiv
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Main Authors: Zhang, Yulin, Shell, Dylan A.
Format: Preprint
Published: 2023
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author Zhang, Yulin
Shell, Dylan A.
author_facet Zhang, Yulin
Shell, Dylan A.
contents What is the minimal information that a robot must retain to achieve its task? To design economical robots, the literature dealing with reduction of combinatorial filters approaches this problem algorithmically. As lossless state compression is NP-hard, prior work has examined, along with minimization algorithms, a variety of special cases in which specific properties enable efficient solution. Complementing those findings, this paper refines the present understanding from the perspective of parameterized complexity. We give a fixed-parameter tractable algorithm for the general reduction problem by exploiting a transformation into clique covering. The transformation introduces new constraints that arise from sequential dependencies encoded within the input filter -- some of these constraints can be repaired, others are treated through enumeration. Through this approach, we identify parameters affecting filter reduction that are based upon inter-constraint couplings (expressed as a notion of their height and width), which add to the structural parameters present in the unconstrained problem of minimal clique covering. Compared with existing work, we precisely identify and quantitatively characterize those features that contribute to the problem's hardness: given a problem instance, the combinatorial core may be a fraction of the instance's full size, with a small subset of constraints needing to be considered, and even those may have directly identifiable couplings that collapse degrees of freedom in the enumeration.
format Preprint
id arxiv_https___arxiv_org_abs_2309_06664
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A fixed-parameter tractable algorithm for combinatorial filter reduction
Zhang, Yulin
Shell, Dylan A.
Robotics
What is the minimal information that a robot must retain to achieve its task? To design economical robots, the literature dealing with reduction of combinatorial filters approaches this problem algorithmically. As lossless state compression is NP-hard, prior work has examined, along with minimization algorithms, a variety of special cases in which specific properties enable efficient solution. Complementing those findings, this paper refines the present understanding from the perspective of parameterized complexity. We give a fixed-parameter tractable algorithm for the general reduction problem by exploiting a transformation into clique covering. The transformation introduces new constraints that arise from sequential dependencies encoded within the input filter -- some of these constraints can be repaired, others are treated through enumeration. Through this approach, we identify parameters affecting filter reduction that are based upon inter-constraint couplings (expressed as a notion of their height and width), which add to the structural parameters present in the unconstrained problem of minimal clique covering. Compared with existing work, we precisely identify and quantitatively characterize those features that contribute to the problem's hardness: given a problem instance, the combinatorial core may be a fraction of the instance's full size, with a small subset of constraints needing to be considered, and even those may have directly identifiable couplings that collapse degrees of freedom in the enumeration.
title A fixed-parameter tractable algorithm for combinatorial filter reduction
topic Robotics
url https://arxiv.org/abs/2309.06664