I am using boost::numeric::odeint ODE solvers and have a question about them. The instructions says bulirsch_stoer is a Stepper with step size and order control. Besides, the order is a variable the user could change. I look at the header file but didn't get a idea? Does anyone have any solution?
both, the order and the stepsize, are adjusted by the bulirsch-stoer method internally by a rather complicated algorithm. The user has no way to influence the order manually.
If you want a stepper with a specific order, you should consider a multi-step method like Adams-Bashforth, where you specify the order up-front. However, there the order can not be changed during the integration.