cl = get_clust(matrix, ids, ndomain, noc_parms);

matrix: input pairwise Sc score matrix

treefit

(domain, ndomain, cl[i], &score, &rms, &length, &nfit, Pij,
		 Dij, dist, Pijp, 1, 0, parms)

cl[i]: cluster i
score: ? (scalar)
rms: 
length 
nfit
These are all scalars:
Pij
Dij
dist
Pijp