Approximation Algorithms for Demand Strip Packing

Gálvez, Waldo; Grandoni, Fabrizio; Ameli, Afrouz Jabal; Khodamoradi, Kamyar

doi:10.48550/arxiv.2105.08577

Cited by 1 publication

(1 citation statement)

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“…Variants of 2SP where items can be sliced using vertical cuts find applications in resource allocation problems [3,16,19]. Many packing algorithms [28,25,8] solve the sliceable version of the problem as a subroutine.…”

Section: :5mentioning

confidence: 99%

Tight Approximation Algorithms for Geometric Bin Packing with Skewed Items

Khan

Sharma

2023

Algorithmica

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In the Two-dimensional Bin Packing (2BP) problem, we are given a set of rectangles of height and width at most one and our goal is to find an axis-aligned nonoverlapping packing of these rectangles into the minimum number of unit square bins. The problem admits no APTAS and the current best approximation ratio is 1.406 by Bansal and Khan [SODA'14]. A well-studied variant of the problem is Guillotine Two-dimensional Bin Packing (G2BP), where all rectangles must be packed in such a way that every rectangle in the packing can be obtained by recursively applying a sequence of end-to-end axis-parallel cuts, also called guillotine cuts. Bansal, Lodi, and Sviridenko [FOCS'05] obtained an APTAS for this problem. Let λ be the smallest constant such that for every set I of items, the number of bins in the optimal solution to G2BP for I is upper bounded by λ opt(I) + c, where opt(I) is the number of bins in the optimal solution to 2BP for I and c is a constant. It is known that 4/3 ≤ λ ≤ 1.692. Bansal and Khan [SODA'14] conjectured that λ = 4/3. The conjecture, if true, will imply a (4/3 + ε)-approximation algorithm for 2BP. According to convention, for a given constant δ > 0, a rectangle is large if both its height and width are at least δ, and otherwise it is called skewed. We make progress towards the conjecture by showing λ = 4/3 for skewed instance, i.e., when all input rectangles are skewed. Even for this case, the previous best upper bound on λ was roughly 1.692. We also give an APTAS for 2BP for skewed instance, though general 2BP does not admit an APTAS.

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