  We consider a system of particles interacting via a purely repulsive,
soft-core potential recently introduced to model effective pair interactions
between dendrimers, which is expected to lead to the formation of crystals with
multiple occupancy of the lattice sites. The phase diagram is investigated by
density-functional theory (DFT) without making any a priori assumption on the
functional form of the density profile or on the type of crystal lattice. As
the average density $\rho$ is increased, the system displays first a transition
from a fluid to a bcc phase, and subsequently to hcp and fcc phases. In the
inhomogeneous region, the behavior is that found in previous investigations of
this class of cluster-forming potentials. Specifically, the particles arrange
into clusters strongly localized at the lattice sites, and the lattice constant
depends very weakly on $\rho$, leading to an occupancy number of the sites
which is a nearly linear function of $\rho$. These results are compared to
those predicted by the more widespread approach, in which the DFT minimization
is carried out by representing the density profile by a given functional form
depending on few variational parameters. We find that for the model potential
studied here, the latter approach recovers most of the predictions of the
unconstrained minimization.
