Cutoff section. The local or total indices can be calculated taking into consideration all elements in matrices of algebraic forms [KA (Keep All]. However, the software avails other options in cutoff, such as, 1) SRW (Self-Returning Walk). Here only diagonal elements of algebraic forms are taken into account, 2) NSWR (Non Self-Returning Walk). Only off-diagonal elements of algebraic forms are taken into account and 3) LG[P/L] (lag P/L). The idea of a lag is taken from autocorrelation descriptors, only that here the meaning is quite different. This cutoff is applied to the elements in the algebraic forms matrices, namely, NS, SS, DS, MP. Here, if lag P/L is used, the matrix elements are different from zero for relations of atoms that have a topological/geometric distance, equal/less to a specified k value.