  We present a computer simulation model that is a one-to-one copy of an
experimental realization of Wheeler's delayed choice experiment that employs a
single photon source and a Mach-Zehnder interferometer composed of a 50/50
input beam splitter and a variable output beam splitter with adjustable
reflection coefficient $R$ (V. Jacques {\sl et al.}, Phys. Rev. Lett. 100,
220402 (2008)). For $0\le R\le 0.5$, experimentally measured values of the
interference visibility $V$ and the path distinguishability $D$, a parameter
quantifying the which-path information WPI, are found to fulfill the
complementary relation $V^2+D^2\le 1$, thereby allowing to obtain partial WPI
while keeping interference with limited visibility. The simulation model that
is solely based on experimental facts, that satisfies Einstein's criterion of
local causality and that does not rely on any concept of quantum theory or of
probability theory, reproduces quantitatively the averages calculated from
quantum theory. Our results prove that it is possible to give a particle-only
description of the experiment, that one can have full WPI even if D=0, V=1 and
therefore that the relation $V^2+D^2\le 1$ cannot be regarded as quantifying
the notion of complementarity.
