Initializes rodeo's built-in ODE solver. This method must be called
prior to using step.
invisible(NULL)
Name(s) of fortran source file(s) where a module with the
fixed name 'functions' is implemented. This module must contain all
user-defined functions referenced in process rates or
stoichiometric factors. Can be NULL, the name of a single file, or
a vector of file names if the Fortran code is split over several files.
Name of a the solver. Currently, 'rk5' is the only supported value (Runge-Kutta method of Cash and Karp).
To perform integration with the solvers from package
deSolve use compile instead of this
method.