Goto

Collaborating Authors

 monotone submodular function



The Power of Optimization from Samples

Neural Information Processing Systems

We consider the problem of optimization from samples of monotone submodular functions with bounded curvature. In numerous applications, the function optimized is not known a priori, but instead learned from data. What are the guarantees we have when optimizing functions from sampled data? In this paper we show that for any monotone submodular function with curvature c there is a (1 c)/(1 + c c2) approximation algorithm for maximization under cardinality constraints when polynomially-many samples are drawn from the uniform distribution over feasible sets. Moreover, we show that this algorithm is optimal. That is, for any c< 1, there exists a submodular function with curvature c for which no algorithm can achieve a better approximation. The curvature assumption is crucial as for general monotone submodular functions no algorithm can obtain a constant-factor approximation for maximization under a cardinality constraint when observing polynomially-many samples drawn from any distribution over feasible sets, even when the function is statistically learnable.








The Cost of Consistency: Submodular Maximization with Constant Recourse

arXiv.org Machine Learning

In this work, we study online submodular maximization, and how the requirement of maintaining a stable solution impacts the approximation. In particular, we seek bounds on the best-possible approximation ratio that is attainable when the algorithm is allowed to make at most a constant number of updates per step. We show a tight information-theoretic bound of $\tfrac{2}{3}$ for general monotone submodular functions, and an improved (also tight) bound of $\tfrac{3}{4}$ for coverage functions. Since both these bounds are attained by non poly-time algorithms, we also give a poly-time randomized algorithm that achieves a $0.51$-approximation. Combined with an information-theoretic hardness of $\tfrac{1}{2}$ for deterministic algorithms from prior work, our work thus shows a separation between deterministic and randomized algorithms, both information theoretically and for poly-time algorithms.


Reviews: Multi-objective Maximization of Monotone Submodular Functions with Cardinality Constraint

Neural Information Processing Systems

The paper proposes three efficient multiobjective submodular maximization algorithms. I like this paper, and has no clear objection to the paper. The techniques (using one-pass procedure for picking the heavy elements, separating MWU and the continuous greedy) are simple and effective, and seem to be applied for more general problems. The first paragraph (many well known ...) is arguable. There are many non-submodular combinatorial optimization problems.