Online Vector Packing
Talkat Optimization and Decision-Making Under Uncertainty (Simons Institute, September 2016) · 2016-09-19..09-23
summary
General online vector packing is essentially hopeless in the worst case: competitive ratio grows Θ(d) for arbitrary vectors, and an information-theoretic lower bound nearly D^{1−ε} appears for the b=1 case. Assuming every coordinate ≤1/B yields sublinear bounds (upper ~D^{1/(something like B·log D)}, lower ~D^{1/B}). A e-competitive fractional sliding-window algorithm uses density 1/x; randomized rounding plus spillover yields an unsplittable randomized ~e-competitive algorithm for tiny vectors (sizes ≲ ε^2 log D), and a lower bound approaching e via duality shows e is essentially tight as d→∞.
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chapters (26)
- 0:00Intro
- 1:45amazon Cloud Computing
- 5:53Two Dimensional Interpretation
- 6:18Vector Bin Packing Problem
- 6:46Online Algorithms
- 7:11Example: First Fit
- 9:42VBP(B=1) Lower Bound
- 12:24Online Vector Packing • In practice, task demands are small compared to capacity
- 14:13VBP Lower Bound
- 16:41Closing The Gap
- 17:49Two Dimensional Vector Packing
- 18:25Algorithm for arbitrary dimension
- 18:42Our Techniques
- 19:05The Splittable model
- 19:42Phase 1: Splittable Model - OPT
- 21:13Multidimensional Setting
- 21:27Sliding Window Algorithm
- 29:10Randomized Unsplittable Algorithm
- 31:27Proof Idea
- 32:18(1 + ε)e-competitive deterministic Alg
- 36:04Lower Bound (d=2)
- 37:52Phase 2 ALG opens additional cA bins by end of Phase 2
- 39:46Lower Bound for arbitrary d
- 45:56Online Lower Bounds via Duality
- 47:27Conclusions
- 48:04Open Problems
