Problem Variants

Algorithms

Offline

Backward-Recurrent Capacity Provisioning [1]

SSCO - Fractional - Uni-Dimensional

Stays within bounds on the optimal solution moving backwards in time.

Convex Optimization

SCO - Fractional

Finds the minimizer of a convex objective.

Graph-Based Optimal Algorithm (in one dimension) [5]

SSCO - Integral - Uni-Dimensional

Finds a shortest path in a graph using dynamic programming (in polynomial time).

Graph-Based Optimal Algorithm [9]

SSCO - Integral

Finds a shortest path in a graph using dynamic programming (not in polynomial time).

Graph-Based Polynomial-Time Approximation Scheme [9]

SSCO - Integral

Extends the graph-based optimal algorithm by only considering a subset of the decision space to achieve a better performance.

Static Fractional Optimum

SCO - Fractional

Solves a smaller problem than Convex Optimization to obtain an optimal static solution.

Static Integral Optimum

SCO - Integral

Cycles through all possible configurations to find the optimal static integral solution. Convexity is used to stop the search of the decision space quickly in practice, however, the worst-case runtime is exponential.

Online

Lazy Capacity Provisioning [1]

SSCO - Fractional - Uni-Dimensional - 3-competitive

Lazily stays within fractional bounds on the decision space.

Lazy Capacity Provisioning [5]

SSCO - Integral - Uni-Dimensional - 3-competitive (optimal for a deterministic algorithm)

Lazily stays within integral bounds on the decision space.

Memoryless algorithm [3]

SSCO - Fractional - Uni-Dimensional - 3-competitive (optimal for a memoryless algorithm)

Moves towards the minimizer of the hitting cost balancing the paid movement cost. Special case of Primal Online Balanced Descent.

Probabilistic Algorithm [3]

SSCO - Fractional - Uni-Dimensional - 2-competitive (optimal)

Constructs a probability distribution of well-performing configurations over time.

Randmoly Biased Greedy [4]

SCO - Fractional - Uni-Dimensional - 2-competitive (optimal)

Uses a work function to balance hitting and movement costs.

Randomized Integral Relaxation [5]

SSCO - Integral - Uni-Dimensional - 2-competitive (optimal)

Randomly rounds solutions of any 2-competitive fractional algorithm.

Lazy Budgeting for SLO [8]

SLO - Integral - 2d-competitive (optimal for a deterministic algorithm)

Keeps servers active for some minimum time delta even when they are not use to balance hitting costs and movement costs.

Lazy Budgeting for SLO (randomized) [8]

SLO - Integral - (e / (e - 1))d-competitive

Keeps servers active for some minimum time delta even when they are not use to balance hitting costs and movement costs.

Lazy Budgeting for SBLO [9]

SBLO - Integral - 2d + 1 + \epsilon-competitive

Keeps servers active for some minimum time delta even when they are not use to balance hitting costs and movement costs.

Online Gradient Descent [4]

SCO - Fractional

Achieves sublinear regret by learning the static offline optimum.

Primal Online Balanced Descent [6]

SCO - Fractional - 3+\mathcal{O}(1/\alpha)-competitive for the \ell_2 norm and locally \alpha-polyhedral hitting costs, \mathcal{O}(\sqrt{d})-competitive for the \ell_1 norm; mirror map must be m-strongly convex and M-Lipschitz smooth in the switching cost norm

Takes a gradient step orthogonal to some landing level set balancing costs in the primal space.

Dual Online Balanced Descent [6]

SCO - Fractional - mirror map must be m-strongly convex and M-Lipschitz smooth in the switching cost norm

Takes a gradient step orthogonal to some landing level set balancing costs in the dual space. Achieves sublinear regret.

Greedy Online Balanced Descent [7]

SCO - Fractional - \mathcal{O}(1 / \sqrt{m})-competitive for m-quasiconvex hitting costs and \ell_2-squared switching costs

Takes a normal OBD-step and then an additional step directly towards the minimizer of the hitting cost depending on the convexity parameter m.

Regularized Online Balanced Descent [7]

SCO - Fractional - \mathcal{O}(1 / \sqrt{m})-competitive (optimal) for m-strongly convex and differentiable hitting costs and switching costs modeled as the Bregman divergence where the potential function is \alpha-strongly convex, \beta-strongly smooth, differentiable, and its Fenchel Conjugate is differentiable; \Omega(1/m)-competitive for m-quasiconvex hitting costs and \ell_2-squared switching costs

Using a computationally simpler local view.

Receding Horizon Control [2]

SSCO - Fractional - (1 + \Omega(\beta/e_0))-competitive where e_0 is the idle cost and \beta is the scaling of the Manhattan distance; when uni-dimensional the competitive ratio is 1 + \mathcal{O}(1/w)

Averaging Fixed Horizon Control [2]

SSCO - Fractional - 1 + \mathcal{O}(1/w)-competitive

References

  1. Minghong Lin and Adam Wierman and Lachlan L. H. Andrew and Eno Thereska. Dynamic right-sizing for power-proportional data centers. 2011.
  2. Minghong Lin and Zhenhua Liu and Adam Wierman and Lachlan L. H. Andrew. Online Algorithms for Geographical Load Balancing. 2012.
  3. Nikhil Bansal and Anupam Gupta and Ravishankar Krishnaswamy and Kirk Pruhs and Kevin Schewior and Cliff Stein. A 2-Competitive Algorithm For Online Convex Optimization With Switching Costs. 2015.
  4. Lachlan L. H. Andrew and Siddharth Barman and Katrina Ligett and Minghong Lin and Adam Myerson and Alan Roytman and Adam Wierman. A Tale of Two Metrics: Simultaneous Bounds on Competitiveness and Regret. 2015.
  5. Susanne Albers and Jens Quedenfeld. Optimal Algorithms for Right-Sizing Data Centers. 2018.
  6. Niangjun Chen and Gautam Goel and Adam Wierman. Smoothed Online Convex Optimization in High Dimensions via Online Balanced Descent. 2018.
  7. Gautam Goel and Yiheng Lin and Haoyuan Sun and Adam Wierman. Beyond Online Balanced Descent: An Optimal Algorithm for Smoothed Online Optimization. 2019.
  8. Susanne Albers and Jens Quedenfeld. Algorithms for Energy Conservation in Heterogeneous Data Centers. 2021.
  9. Susanne Albers and Jens Quedenfeld. Algorithms for Right-Sizing Heterogeneous Data Centers. 2021.