Aspects of Efficient Focusing

This paper refers to a diagnostic engine based on de Kleer’s GDE. It discusses two aspects of efficient focusing: First, an ATMS is presented that combines focusing techniques with the lazy label evaluation. Second, a candidate generator is presented that prunes the search space using a preference ordering and the knowledge about the last conflict that ruled out a diagnosis. The preferred candidates are generated sequentially according to a predefined priority ordering. That ordering can be used to focus both, the ATMS and the candidate generator, on a constant number of diagnoses.