4.16 The Detour-Path Matrix

The detour-path matrix, denoted by pDM, is similarly defined as the vertex-distance-path matrix, that is, the matrix pDM is a square symmetric V × V matrix whose off-diagonal elements i,j count all paths of any length that are included within the longest path between vertex i and j [218]. Each element i,j of the pDM is computed from the corresponding detour matrix as follows:

[pDM]ij=
[DM]ij + 1          if ij
2
     
  0                            otherwise                          (67)    

The detour-path matrix of G1 (see structure A in Figure 2) is given below.

pDM(G1)=
0
1
3
15
10
15
21
1
0
1
10
6
10
15
3
1
0
6
3
6
3
15
10
6
0
6
4
6
10
6
3
6
0
6
10
15
10
6
4
6
0
1
21
15
10
6
10
1
0

The hyper-detour index can be obtained from the detour-path matrix. For acyclic graphs, the detour-path matrix is equal to the distance-path matrix and consequently, the hyper-detour index for acyclic graphs is equal to the hyper-distance-path index obtained from the distance-path matrix.

<< . . . >>