In order to compare the CGIs predicted by CpGCluster with different values of d，we compute four features for each CGI, first is the CGI length，second is the CG content, the third is CpG O/E ratio of the CGI，and the last is CpG density：

Here, N is the length of the CGI, CpGNum, CNum and GNum represent the number of CpG, number of C, number of G respectively.