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. 2012 Mar 5;7(3):e32906. doi: 10.1371/journal.pone.0032906

Table 2. Spectral features.

Feature Index Feature Name Feature Explanation
20 Largest eigenvalue adjacency Largest valued eigenvalue
21 Second Largest eigenvalue adjacency Second largest valued eigenvalue
22 Trace of adjacency Sum of the eigenvalues of the adjancency matrix.
23 Energy of adjacency Squared sum of the eigenvalues of the adjancency matrix.
24 Number of zeros normalized Laplacian Number of eigenvalues that are 0.
25 Lower Slope The slope of the line for the eigenvalues that are between 0 and 1 when sorted and plotted.
26 Number of ones normalized Laplacian Number of eigenvalues that are 1.
27 Upper Slope The slope of the line for the eigenvalues that are between 1 and 2 when sorted and plotted.
28 Number of twos normalized Laplacian Number of eigenvalues that are 2.
29 Trace of Laplacian Sum of the eigenvalues
30 Energy of Laplacian Squared sum of the eigenvalues