Faster min–max resource sharing in theory and practice

• Published in: Mathematical programming computation Vol. 3; no. 1; pp. 1 - 35
• Main Authors: Müller, Dirk, Radke, Klaus, Vygen, Jens
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.03.2011
• Subjects: Full Length Paper; Mathematics; Mathematics and Statistics; Mathematics of Computing; Operations Research/Decision Theory; Optimization; Theory of Computation; Fully polynomial approximation scheme; Global routing; Chip design; Min–max resource sharing; Fractional packing; 90C06; 90C90; 90C59; 90C48; 90C27; Parallelization
• ISSN: 1867-2949; 1867-2957
• DOI: 10.1007/s12532-011-0023-y

We consider the (block-angular) min–max resource sharing problem, which is defined as follows. Given finite sets of resources and of customers, a convex set , called block, and a convex function for every , the task is to find approximately attaining . As usual we assume that g c can be computed efficiently and we have a constant σ  ≥ 1 and oracle functions , called block solvers, which for and return an element with . We describe a simple algorithm which solves this problem with an approximation guarantee σ (1 +  ω ) for any ω  > 0, and whose running time is for any fixed σ  ≥ 1, where θ is the time for an oracle call. This generalizes and improves various previous results. We also prove other bounds and describe several speed-up techniques. In particular, we show how to parallelize the algorithm efficiently. In addition we review another algorithm, variants of which were studied before. We show that this algorithm is almost as fast in theory, but it was not competitive in our experiments. Our work was motivated mainly by global routing in chip design. Here the blocks are mixed-integer sets (whose elements are associated with Steiner trees), and we combine our algorithm with randomized rounding. We present experimental results on instances resulting from recent industrial chips, with millions of customers and resources. Our algorithm solves these instances nearly optimally in less than two hours.