TY - JOUR T1 - A unified approach to scheduling on unrelated parallel machines JF - J. ACM Y1 - 2009 A1 - Kumar,V. S. Anil A1 - Marathe,Madhav V. A1 - Parthasarathy,Srinivasan A1 - Srinivasan, Aravind KW - Approximation algorithms KW - Randomized rounding KW - scheduling under multiple criteria AB - We develop a single rounding algorithm for scheduling on unrelated parallel machines; this algorithm works well with the known linear programming-, quadratic programming-, and convex programming-relaxations for scheduling to minimize completion time, makespan, and other well-studied objective functions. This algorithm leads to the following applications for the general setting of unrelated parallel machines: (i) a bicriteria algorithm for a schedule whose weighted completion-time and makespan simultaneously exhibit the current-best individual approximations for these criteria; (ii) better-than-two approximation guarantees for scheduling to minimize the Lp norm of the vector of machine-loads, for all 1 < p < ∞; and (iii) the first constant-factor multicriteria approximation algorithms that can handle the weighted completion-time and any given collection of integer Lp norms. Our algorithm has a natural interpretation as a melding of linear-algebraic and probabilistic approaches. Via this view, it yields a common generalization of rounding theorems due to Karp et al. [1987] and Shmoys & Tardos [1993], and leads to improved approximation algorithms for the problem of scheduling with resource-dependent processing times introduced by Grigoriev et al. [2007]. VL - 56 SN - 0004-5411 UR - http://doi.acm.org/10.1145/1552285.1552289 CP - 5 M3 - 10.1145/1552285.1552289 ER -