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Bayesian Optimization in Linear Time
Schneider, Jesse, Welch, William J.
Bayesian optimization is a sequential method for minimizing objective functions that are expensive to evaluate and about which few assumptions can be made. By using all gathered data to train a Gaussian process model for the function and adaptively employing a mixture of global exploration and local exploitation, this method has been used for optimization in many fields including machine learning, automotive engineering and reinforcement learning. However, the standard method suffers from two problems: 1) with cubic computational complexity in the training-set size it eventually becomes computationally infeasible to train the model, and 2) globally modeling the objective function is not necessarily optimal given the local nature of minimization. Using flexible and recursive binary partitioning of the search space, we adapt both the modeling and acquisitive aspects of standard Bayesian optimization to work harmoniously with the partitioning scheme, thereby ameliorating both standard shortcomings. We compare our method against a commonly used Bayesian optimization library on seven challenging test functions, ranging in dimensionality from $6$ to $124$, and show that our method achieves superior optimization performance in all tests. In addition our method has linear computational complexity.
Polyhedron Attention Module: Learning Adaptive-order Interactions Anonymous Author(s) Affiliation Address email Appendixes1
Contents2 ADeriving Eq. 2. 23 BThe hyperplane set generated by the oblique tree is a superset of that created by the4 ReLU-activated plain DNN 35 CProof of Theorem 1 46 DProof of Theorem 2 57 EProof of Theorem 3 68 FProof of Theorem 4 79 GImplementation Detail 810 We consider a L-layer (L 2) ReLU activated plain DNN module f: Rn0 RnL with input12 x Rp. Eq. 2 in the main text can be30 obtained by rewriting P An oblique tree is a binary tree where each node splits the space by a hyperplane rather than by34 thresholding a single feature. The tree starts with the root of the full input space S, and by recursively35 splitting S, the tree grows deeper. For a D-depth (D 3) binary tree, there are 2D 1 1 internal36 nodes and 2D 1 leaf nodes. As shown in Figure 1, each internal and leaf node maintains a sub-space37 representing a polyhedron in S, and each layer of the tree corresponds to a partition of the input38 space into polyhedrons.
RGMDT: Return-Gap-MinimizingDecisionTree ExtractioninNon-EuclideanMetricSpace
In this paper, we establish an upper bound on the return gap between the oracle expert policy and an optimal decision tree policy. This enables us to recast the DT extraction problem into a novel non-euclidean clustering problem over the local observation and action values space of each agent, with action values as cluster labels and the upper bound on the return gap as clustering loss.