Bulirsch-Stoer constructor question

[kartikkumar]

I'm not able to track this down in the documentation, nor really parse it out of the reference text (Hairer et al.).

I was wondering if someone can shed light on what the factor_x and factor_dxdt terms are. They are set in this example in bulirsch_stoer.cpp to 0.0 and in elliptic_functions.cpp to 1.0 and 0.0 respectively.

Any insights would be greatly appreciated.

[mariomulansky]

Great question. Those variables are not actually used in the algorithm at the moment (which means they are implicitly set to 1). They are part of the interface already, but we never got around to pass them through into the algorithm. I'm not sure about their actual meaning either at this point.