  We are commenting on the article Phys. Rev. {\bf B 65}, 155112 (2002) by G.
Biroli and G. Kotliar in which they make a comparison between two cluster
techniques, the {\it Cellular Dynamical Mean Field Theory} (CDMFT) and the {\it
Dynamical Cluster Approximation} (DCA). Based upon an incorrect implementation
of the DCA technique in their work, they conclude that the CDMFT is a faster
converging technique than the DCA. We present the correct DCA prescription for
the particular model Hamiltonian studied in their article and conclude that the
DCA, once implemented correctly, is a faster converging technique for the
quantities averaged over the cluster. We also refer to their latest response to
our comment where they argue that instead of averaging over the cluster, local
observables should be calculated in the bulk of the cluster which indeed makes
them converge much faster in the CDMFT than in the DCA. We however show that in
their original work, the authors themselves use the cluster averaged quantities
to draw their conclusions in favor of using the CDMFT over the DCA.
