polytope
Linear-Memory and Decomposition-Invariant Linearly Convergent Conditional Gradient Algorithm for Structured Polytopes
Recently, several works have shown that natural modifications of the classical conditional gradient method (aka Frank-Wolfe algorithm) for constrained convex optimization, provably converge with a linear rate when the feasible set is a polytope, and the objective is smooth and strongly-convex. However, all of these results suffer from two significant shortcomings: i) large memory requirement due to the need to store an explicit convex decomposition of the current iterate, and as a consequence, large running-time overhead per iteration ii) the worst case convergence rate depends unfavorably on the dimension In this work we present a new conditional gradient variant and a corresponding analysis that improves on both of the above shortcomings. In particular, both memory and computation overheads are only linear in the dimension, and in addition, in case the optimal solution is sparse, the new convergence rate replaces a factor which is at least linear in the dimension in previous works, with a linear dependence on the number of non-zeros in the optimal solution At the heart of our method, and corresponding analysis, is a novel way to compute decomposition-invariant away-steps. While our theoretical guarantees do not apply to any polytope, they apply to several important structured polytopes that capture central concepts such as paths in graphs, perfect matchings in bipartite graphs, marginal distributions that arise in structured prediction tasks, and more. Our theoretical findings are complemented by empirical evidence that shows that our method delivers state-of-the-art performance.
Learning convex polytopes with margin
We present improved algorithm for properly learning convex polytopes in the realizable PAC setting from data with a margin. Our learning algorithm constructs a consistent polytope as an intersection of about t log t halfspaces with margins in time polynomial in t (where t is the number of halfspaces forming an optimal polytope). We also identify distinct generalizations of the notion of margin from hyperplanes to polytopes and investigate how they relate geometrically; this result may be of interest beyond the learning setting.
- Europe > Germany > Bavaria > Upper Bavaria > Munich (0.04)
- Europe > Poland > Lesser Poland Province > Kraków (0.04)
- Asia > Middle East > Jordan (0.04)
- Banking & Finance (0.93)
- Information Technology > Services (0.68)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Constraint-Based Reasoning (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Learning Graphical Models > Undirected Networks > Markov Models (0.46)
- North America > United States > Massachusetts > Middlesex County > Belmont (0.04)
- North America > United States > Illinois > Cook County > Chicago (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- (3 more...)
- North America > United States > Colorado > Boulder County > Boulder (0.04)
- Asia > Middle East > Jordan (0.04)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- North America > United States > California > Alameda County > Berkeley (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- Asia > Middle East > Jordan (0.04)
- Education (0.68)
- Leisure & Entertainment (0.68)
- Information Technology > Game Theory (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Agents (1.00)
- Information Technology > Artificial Intelligence > Machine Learning (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (0.68)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- North America > United States > California > Alameda County > Berkeley (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- Asia > Middle East > Jordan (0.04)
- Education (0.68)
- Leisure & Entertainment (0.68)
- Information Technology > Game Theory (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Agents (1.00)
- Information Technology > Artificial Intelligence > Machine Learning (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (0.68)
- North America > United States > Virginia (0.04)
- North America > United States > California > San Diego County > San Diego (0.04)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- (4 more...)
- Research Report > Experimental Study (1.00)
- Workflow (0.68)
- Government > Regional Government (0.46)
- Energy (0.45)
- North America > United States > Pennsylvania (0.04)
- North America > United States > Illinois > Cook County > Chicago (0.04)
- Asia > Middle East > Jordan (0.04)