  A variety of electrostatic phenomena, including the structure of electric
double layers and the aggregation of charged colloids and proteins, are
affected by nonuniform electric permittivity. These effects are frequently
ignored in analytical and computational studies, and particularly difficult to
handle in situations where multiple dielectric contrasts are present, such as
in colloids that are heterogeneous in permittivity. We present an extension to
the Iterative Dielectric Solver developed by Barros and Luijten [Phys. Rev.
Lett. 113, 017801 (2014)] that makes it possible to accurately compute the
polarization of anisotropic particles with multiple dielectric contrasts. This
efficient boundary-element method-based approach is applicable to geometries
that are not amenable to other solvers, opening the possibility of studying
collective phenomena of dielectrically anisotropic particles. We provide
insight into the underlying physical reasons for this efficiency.
