allocate com_size per community in FOMD_Rcpp

[kevinushey]

Background

The next Rcpp release (see RcppCore/Rcpp#1513) checks that the operands of a sugar expression, and a vector assigned into a matrix row, column or Range subset, have matching lengths. Previously a longer operand was silently truncated to the length of the left-hand side or target. With that check, clustAnalytics fails its CRAN checks with:

Error: sugar operands have different lengths (2 and 34)

In FOMD_Rcpp(), com_size is allocated with n (the number of vertices) but indexed by community, and then divided into FOMD, which has n_com elements. Old Rcpp read only the first n_com entries, so results were correct. The sibling functions out_degree_fractions_Rcpp() and TPR_coms_Rcpp() already allocate with n_com.

Change

Allocate com_size with n_com.

Testing

R CMD check on the patched package passes against both the current Rcpp branch and released Rcpp 1.1.2.