The diameter of a graph is the length of the shortest path between the most distanced nodes. d measures the extent of a graph and the topological length between two nodes. The number of links (edges) between the furthest nodes (2 and 7) of the above graph is 4. Consequently, the diameter of this graph is 4. The highest value of the topological distance of this matrix (Shimbel distance) is the diameter of the graph (d=4). In the case of a non-oriented graph, the matrix is transposable.