The SINDCLUS algorithm for fitting the ADCLUS and INDCLUS models deals
with a parameter matrix that occurs twice in the model by considering
the two occurrences as independent parameter matrices. This procedure
has been justified empirically by the observation that upon convergen
ce of the algorithm to the global optimum, the two independently treat
ed parameter matrices turn out to be equal. In the present paper, resu
lts are presented that contradict this finding, and a modification of
SINDCLUS is presented which obviates the need for independently treati
ng two occurrences of the same parameter matrix.