The formal rules, the algorithm and the program for functional models verification

The methodology of functional modeling provides visual and understandable means of describing the domain for a wide range of specialists. The paper proposes a formal language for describing a functional model based on graph theory. Within this language, each functional diagram is represented as a graph with marked edges. The nodes of this graph define the function blocks, the edges correspond to the arrows of the diagram. We develop rules for diagram bounds description with special nodes, the arrows positions using the system of roles, branching arrows as a set of special nodes and multiple edges. The hierarchy which links individual diagrams into a single model, is defined by the relation of decomposition on graphs. We form rules that connect the arrows of the parent and child functional diagrams in correctly constructed functional models. To verify these rules, a functional model verification algorithm has been developed. This algorithm is implemented by means of logic programming using the PROLOG language. The structure of the fact base for describing the relations of decomposition, nodes, and edges of graphs is proposed. A set of predicates is provided to verify the correctness of the functional model description.