Refraction algorithm for production systems with content addressable memory

摘要

An array processor system is provided with a system to implement a refraction algorithm to prevent incorrect expert system rule firing based on stale or future data, in those production system expert systems which employ content addressable memories for storage of the expert system's facts and its processing control information. The computer system is especially suitable for system which have expert system resources, and there are generic applications of refraction which can be used in any architecture, from scalar to massively parallel, and an associative memory or content addressable memory. The system need not use the RETE algorithm. The computer expert system, has an inference engine and a refraction check mechanism. It is provided with a time stamping mechanism. The computer memory will have working memory elements associated with the processing elements of the array processor. The array processor has a content addressable memory. A knowledge base is stored in the computer memory, and this base can be distributed among processing elements or pickets of the system. Each processing element or picket will have memory directly or indirectly associated with the processing element. The time stamping mechanism will order and identify the working memory elements. The computer program which forms the basis for the inferencing process controller system has controls which work with the operations of rules provided for examination of information in the system representing facts. The inferencing process contains the constraints which are subject to refraction checking. The refraction check system prevents the rule from subsequent firings on stale data. The refraction check prevents a rule from firing using data asserted into the inferencing system at a time later than the rule was selected for evaluation by the inferencing process. With the expert system resources the computer system instruction processing unit uses the content addressable memory provided by the memory store working memory elements to store the knowledge base.