  We present a cross-language C++/Python program for simulations of quantum
mechanical systems with the use of Quantum Monte Carlo (QMC) methods. We
describe a system for which to apply QMC, the algorithms of variational Monte
Carlo and diffusion Monte Carlo and we describe how to implement theses methods
in pure C++ and C++/Python. Furthermore we check the efficiency of the
implementations in serial and parallel cases to show that the overhead using
Python can be negligible.
