Nice piece of Smath.

ODE rkfixed Orbit.sm (10.33 KiB) downloaded 966 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 (36.62 KiB) downloaded 864 time(s).
ODE Van der Pol.sm (36.97 KiB) downloaded 793 time(s).
ODE RK Unsolved [Valery].sm (45.22 KiB) downloaded 678 time(s).