Online Discovery of Feature Dependencies

Online representational expansion techniques have improved the learning speed of existing reinforcement learning (RL) algorithms in low dimensional domains, yet existing online expansion methods do not scale well to high dimensional problems. We conjecture that one of the main difficulties limiting this scaling is that features defined over the full-dimensional state space often generalize poorly. Hence, we introduce incremental Feature Dependency Discovery (iFDD) as a computationally-inexpensive method for representational expansion that can be combined with any online, value-based RL method that uses binary features. Unlike other online expansion techniques, iFDD creates new features in low dimensional subspaces of the full state space where feedback errors persist. We provide convergence and computational complexity guarantees for iFDD, as well as showing empirically that iFDD scales well to high dimensional multi-agent planning domains with hundreds of millions of state-action pairs.