Reward Potentials for Planning with Learned Neural Network Transition
  Models
  Optimal planning with respect to learned neural network (NN) models in
continuous action and state spaces using mixed-integer linear programming
(MILP) is a challenging task for branch-and-bound solvers due to the poor
linear relaxation of the underlying MILP model. For a given set of features,
potential heuristics provide an efficient framework for computing bounds on
cost (reward) functions. In this paper, we model the problem of finding optimal
potential bounds for learned NN models as a bilevel program, and solve it using
a novel finite-time constraint generation algorithm. We then strengthen the
linear relaxation of the underlying MILP model by introducing constraints to
bound the reward function based on the precomputed reward potentials.
Experimentally, we show that our algorithm efficiently computes reward
potentials for learned NN models, and that the overhead of computing reward
potentials is justified by the overall strengthening of the underlying MILP
model for the task of planning over long horizons.
