Nice piece of Smath.

ODE rkfixed Orbit.sm (10 KiB) downloaded 164 time(s).

Hello Jean,

Thank you for your continuing contributions

By the way, did you use rkfixed() on purpose. As usual, did you try to use, say, Rkadapt() or any other solver different than rkfixed(). As we mentioned many times - rkfixed() is not the solver of choice anyway.

Regards,
Radovan

Wrote

Hello Jean,

Thank you for your continuing contributions

By the way, did you use rkfixed() on purpose. As usual, did you try to use, say, Rkadapt() or any other solver different than rkfixed(). As we mentioned many times - rkfixed() is not the solver of choice anyway.

Regards,
Radovan

Hello Radovan:

Rkadapt represents a pure Newton stable ellipse in this work sheet.
"rkfixed" is a much different story wrt launching satellites.
Some systems have possibly "stiff" solvers, some none directly in Smath
... visit Valery "forced rkfixed".

Cheers Radovan, Jean

ODE rkfixed Orbit.sm (36 KiB) downloaded 62 time(s).
ODE Van der Pol.sm (36 KiB) downloaded 55 time(s).
ODE RK Unsolved [Valery].sm (45 KiB) downloaded 51 time(s).