Software for Iterative Optimization of Plans

The Iterative Plan Optimization computer program automatically optimizes plans with respect to preferences expressed by human planners. This program incorporates a generalization of commonly occurring plan-quality metrics to provide a language for expression of preferences. The program implements a technique of iterative optimization that is a generalization of a prior technique of iterative repair, in which conflicts are detected and addressed one at a time until either no conflicts exist or a user-defined time limit has been exceeded. During iterative optimization, low-scoring preferences are detected and addressed individually until the maximum score is attained or until a user-defined time limit has been exceeded. A preference is a quality metric for a plan variable and can be improved by modifying the plan in a manner similar to that of repairing it. Plan modifications can include moving, creating, and deleting activities. For each preference, a domain-independent improvement-expert subprogram automatically generates the subset of modifications that could potentially improve the preference score.