Optimally stable plan repair

Plan repair is the problem of solving a given planning problem by using a solution plan of a similar problem. This paper presents the first approach where the repair has to be done optimally, that is, we aim at finding a minimum distance plan from an input plan; we do so by introducing a number of compilation schemes that convert a classical planning problem into another where optimal plans correspond to plans with the minimum distance from an input plan. We also address the problem of finding a minimum distance plan from a set of input plans, instead of just one plan. Our experiments using a number of planners show that such a simple approach can solve many problems optimally and more effectively than replanning from scratch for a large number of cases. Also, the approach proves competitive with ${\mathsf{LPG}\textrm{-}\mathsf{adapt}}$ , a state-of-the-art approach for the plan repair problem.