  In complex dynamical systems, the detection of coupling and its direction
from observed time series is a challenging task. We study coupling in coupled
Duffing oscillator systems in regular and chaotic dynamical regimes. By
observing the conditional mutual information (CMI) based on the Shannon
entropy, we successfully infer the direction of coupling for different system
regimes. Moreover, we show that in the weak coupling limit the values of CMI
can be used to infer the coupling parameters by computing the derivative of the
conditional mutual information with respect to the coupling strength, called
the information susceptibility. The complete numerical implementation is
available at https://repo.ijs.si/mbresar/duffing-cmi.
