783 research outputs found

    Vector Bin Packing with Multiple-Choice

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    We consider a variant of bin packing called multiple-choice vector bin packing. In this problem we are given a set of items, where each item can be selected in one of several DD-dimensional incarnations. We are also given TT bin types, each with its own cost and DD-dimensional size. Our goal is to pack the items in a set of bins of minimum overall cost. The problem is motivated by scheduling in networks with guaranteed quality of service (QoS), but due to its general formulation it has many other applications as well. We present an approximation algorithm that is guaranteed to produce a solution whose cost is about lnD\ln D times the optimum. For the running time to be polynomial we require D=O(1)D=O(1) and T=O(logn)T=O(\log n). This extends previous results for vector bin packing, in which each item has a single incarnation and there is only one bin type. To obtain our result we also present a PTAS for the multiple-choice version of multidimensional knapsack, where we are given only one bin and the goal is to pack a maximum weight set of (incarnations of) items in that bin

    An FPTAS for the Δ\Delta-modular multidimensional knapsack problem

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    It is known that there is no EPTAS for the mm-dimensional knapsack problem unless W[1]=FPTW[1] = FPT. It is true already for the case, when m=2m = 2. But, an FPTAS still can exist for some other particular cases of the problem. In this note, we show that the mm-dimensional knapsack problem with a Δ\Delta-modular constraints matrix admits an FPTAS, whose complexity bound depends on Δ\Delta linearly. More precisely, the proposed algorithm complexity is O(TLP(1/ε)m+3(2m)2m+6Δ),O(T_{LP} \cdot (1/\varepsilon)^{m+3} \cdot (2m)^{2m + 6} \cdot \Delta), where TLPT_{LP} is the linear programming complexity bound. In particular, for fixed mm the arithmetical complexity bound becomes O(n(1/ε)m+3Δ). O(n \cdot (1/\varepsilon)^{m+3} \cdot \Delta). Our algorithm is actually a generalisation of the classical FPTAS for the 11-dimensional case. Strictly speaking, the considered problem can be solved by an exact polynomial-time algorithm, when mm is fixed and Δ\Delta grows as a polynomial on nn. This fact can be observed combining previously known results. In this paper, we give a slightly more accurate analysis to present an exact algorithm with the complexity bound O(nΔm+1), for m being fixed. O(n \cdot \Delta^{m + 1}), \quad \text{ for $m$ being fixed}. Note that the last bound is non-linear by Δ\Delta with respect to the given FPTAS
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