  We examine the stability issue in the inverse problem of determining a scalar
potential appearing in the stationary Schr{\"o}dinger equation in a bounded
domain, from a partial elliptic Dirichlet-to-Neumann map. Namely, the Dirichlet
data is imposed on the shadowed face of the boundary of the domain and the
Neumann data is measured on its illuminated face. We establish a log log
stability estimate for the L2-norm (resp. the H minus 1-norm) of bounded (resp.
L2) potentials whose difference is lying in any Sobolev space of order positive
order.
