This algorithm for the calculation of the complete elliptic
integral (CEI) is presented in papers by Ronald Bulirsch,
Numerical Calculation of Elliptic Integrals and
Elliptic Functions, Numerische Mathematik 7,
78-90 (1965) and Ronald Bulirsch: Numerical Calculation
of Elliptic Integrals and Elliptic Functions III,
Numerische Mathematik 13,305-315 (1969).
If the experiment uses a RungeKuttaIntegration scheme which calculates an internal fractional
error estimate to evolve the Motion equations (not implemented at present in 1.0), then eps is the
allowed fractional error for the step from t to t+dt for a requested time step dt.