  Aggregative games have many industrial applications, and computing an
equilibrium in those games is challenging when the number of players is large.
In the framework of atomic aggregative games with coupling constraints, we show
that variational Nash equilibria of a large aggregative game can be
approximated by a Wardrop equilibrium of an auxiliary population game of
smaller dimension. Each population of this auxiliary game corresponds to a
group of atomic players of the initial large game. This approach enables an
efficient computation of an approximated equilibrium, as the variational
inequality characterizing the Wardrop equilibrium is of smaller dimension than
the initial one. This is illustrated on an example in the smart grid context.
