Abstract: A knowledge compilation/pattern reasoning system has two subsystems: a pattern generating subsystem for interpreting human representation of knowledge and physical models and transforming them into pattern data, and an executing subsystem for analyzing states by using the generated pattern data and decision criterion data. An operation system of the kind adopting pattern type reasoning may be loaded with only the executing subsystem which uses pattern data compiled by the pattern generating subsystem beforehand, for the purpose of implementing high-speed execution. Since the transformation of human representation of knowledge and physical models into pattern data is effected by the pattern generating subsystem which is independent of the executing system, human representation of knowledge and physical models and pattern data are desirably interfaced to each other.