Abstract
We study the task of gathering k energy-constrained mobile agents in an undirected edge-weighted graph. Each agent is initially placed on an arbitrary node and has a limited amount of energy, which constrains the distance it can move. Since this may render gathering at a single point impossible, we study three variants of near-gathering:
The goal is to move the agents into a configuration that minimizes either (i) the radius of a ball containing all agents, (ii) the maximum distance between any two agents, or (iii) the average distance between the agents. We prove that (i) is polynomial-time solvable, (ii) has a polynomial-time 2-approximation with a matching NP-hardness lower bound, while (iii) admits a polynomial-time \(2(1-\tfrac{1}{k})\)-approximation, but no FPTAS, unless \(\text {P}=\text {NP}\). We extend some of our results to additive approximation.
This work was partially supported by the SNF (project 200021L_156620) and by the ANR (project ANCOR anr-14-CE36-0002-01), while A. Bärtschi was working at ETH Zürich, and E. Bampas and C. Karousatou were working at Aix-Marseille Université. The Los Alamos National Laboratory report number is LA-UR-19-23906.
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Bärtschi, A., Bampas, E., Chalopin, J., Das, S., Karousatou, C., Mihalák, M. (2019). Near-Gathering of Energy-Constrained Mobile Agents. In: Censor-Hillel, K., Flammini, M. (eds) Structural Information and Communication Complexity. SIROCCO 2019. Lecture Notes in Computer Science(), vol 11639. Springer, Cham. https://doi.org/10.1007/978-3-030-24922-9_4
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