  We implement the Wang-Landau algorithm to sample with equal probabilities the
static configurations of a model granular system. The "non-interacting rigid
arch model" used is based on the description of static configurations by means
of splitting the assembly of grains into sets of stable arches. This technique
allows us to build the entropy as a function of the volume of the packing for
large systems. We make a special note of the details that have to be considered
when defining the microstates and proposing the moves for the correct sampling
in these unusual models. We compare our results with previous exact
calculations of the model made at moderate system sizes. The technique opens a
new opportunity to calculate the entropy of more complex granular models.
