ABSTRACT
In parallel with theoretical studies, problems of location, dependence on parameters and branching of periodic trajectories of dynamical systems have been extensively inves-tigated numerically for some time. Several computer codes have been developed for this purpose [DK,HK,KKLN,K] some of which are distributed commercially at present. In most of the underlying algorithms the orbit is represented by one or several of its points. A substantial part of the algorithm consists in continuation: some of the parameters of the system are changed in small steps and, knowing a point on a periodic orbit for some value of the parameter (or, a sequence of such points for several values of the parameter) a nearby point on a periodic orbit for the next value of the parameter is found.
