Hi, Please, correct me if I am wrong. Is PyDSTool a package which aims at providing the functionalities of, say, XPP (http://www.math.pitt.edu/~bard/xpp/xpp.html)? That would be great. Although it is true that much can already be done with the existing SciPy functions, it would be very helpful to have some wrapper or some integrated environment (using ipython, matplotlib, NumPy/Scipy) for the analysis of nonlinear systems. But perhaps this is not exactly what the developers of PyDSTool have in mind. If this is the case, I would appreciate to hear any suggestion about possible Numpy/Scipy-based packages (or tips) that allow users to play (plotting trajectories with different initial conditions, changing parameters, drawing bifurcation diagrams, etc) with nonlinear systems in an interactive and easy way. Best, M.