  We study the simulation of charged systems in the presence of general
boundary conditions in a local Monte Carlo algorithm based on a constrained
electric field. We firstly show how to implement constant-potential, Dirichlet,
boundary conditions by introducing extra Monte Carlo moves to the algorithm.
Secondly, we show the interest of the algorithm for studying systems which
require anisotropic electrostatic boundary conditions for simulating planar
geometries such as membranes.
