  The high energy radiation emitted by black hole X-ray binaries originates in
an accretion disk, hence the variability of the lightcurves mirrors the
dynamics of the disc. We study the time evolution of the emitted flux in order
to find evidences, that low dimensional non-linear equations govern the
accretion flow. Here we test the capabilities of our novel method to find
chaotic behaviour on the two numerical time series describing the motion of a
test particle around a black hole surrounded by a thin massive disc, one being
regular and the other one chaotic.
