I'm continuing the research of a former Ph.D. student in my group requiring the solution of a system of ODEs. On a technical note, they wrote:

> 
> The system of Boltzmann equations behaves numerically stiff. This means that it is advisable to use an implicit method for its numerical solution to achieve acceptable step sizes (and hence acceptable execution times and numerical errors). Here CVODE with its backward differentiation formula with Newton iteration was used as ODE solver. The full Jacobian was computed analytically in every external step.
> 
> 
> 

I don't have access to their code and I'm new in C/C++, so I wonder if

1. Could you recommend a simpler ODE solver to start with?
2. Is there a tutorial/book/example to learn how to use CVODE? I have looked at the official documentation but I'm afraid it is too high-level for me yet.

More details can be provided if needed. Thanks!