[Help-gsl] ODE solver: oscillation around expected value

[Jeroen Meidam]

Hi,

I'm using the gsl ode solver to solve a system of 4 coupled differential 
equations. I've done the exact same thing in python, but needed to 
rewrite it in c. There is one component of the plotted solutions that 
shows an unexpected oscillatory behaviour around the value that python 
gives as aresult.
I have no idea what could cause this. I have tried all the available 
stepping functions and none appear to get rid of this oscillation.

Also, I would expect more differences between the different solving 
methods. If I plot for example the rk2 , rk4, rkf45 and rk8pd solutions 
in one graph, I can't see the slightest bit of difference. Is that to be 
expected?