Graph Representation

The graph class

The basic data structure in fault-diangosis is a bipartite structural graph, encoded in the GraphBipartite class. It contains equation vertices, variable vertices and edges which connect the first two.

The GraphBipartite class is meant to serve only as a data structure, not as an API. All operations on the GraphBipartite object should be handles by the parent GraphInterface object.

All of the vertice and edge classes are subclasses of the GraphElement superclass. The basic property of each GraphElement is its unique id. The IDProvider class objects provides unique IDs for every new GraphElement. A unique ID allows for continuous tracking of graph elements throughout any graph transformations.

Vertex class

Each vertex, either an equation or a variable includes the following properties:

• alias - a human readable name
• edgeIDArray - an array containing the IDs of the edges adjacent to the vertex
• neighbourArray - an array containing the IDs of the immediate neighbouring vertices to this vertex
• matchedTo - the ID of the vertex this vertex is (potentially) matched to

Equations

Equation is a subclass of the Vertex class.

Variables

Variables is a subclass of the Vertex class. They carry qualitative information via the (non-exclusive) properties:

• isKnown - whether this variable is known
• isMeasured - whether this variable is a known system measurement
• isInput, isOutput - whether this variable is a system IO
• isResidual - whether this variable is a residual signal

Edge class

The Edge class encodes most of the structural information of the class, through the following properties:

• weight - weight information reflecting the cost of the solution of the adjacent variable by the adjacent equation
• isDerivative, isIntegral, isNonSolvable - These properties carry the causality information