  We present a self-consistent, real-space calculation of the Wannier functions
of Si and GaAs within density functional theory. We minimize the total energy
functional with respect to orbitals which behave as Wannier functions under
crystal translations and, at the minimum, are orthogonal. The Wannier functions
are used to calculate the total energy, lattice constant, bulk modulus, and the
frequency of the zone-center TO phonon of the two semiconductors with the
accuracy required nowadays in ab-initio calculations. Furthermore, the centers
of the Wannier functions are used to compute the macroscopic polarization of Si
and GaAs in zero electric field. The effective charges of GaAs, obtained by
finite differentiation of the polarization, agree with the results of linear
response theory.
