complex solutions in ode23s

Hi,

Can anyone tell me what situation ode23s sover will give complex solutions?

I am solving diffrential equations that have connection to series functions.

Because my solution for odes23s, x is supposed to be just double numbers,however, mine is giving

complex double x solutions. I'm trying to fix the problems, but I cannot immagine what could be resulting the complex solutions.

Thanks a lot in advance

Answer 1

[Torsten]

I guess there exist some operation in the calculation of your time derivatives that gives a complex result (e.g. sqrt of a negative number, logarithm of a negative number, x^a where x is negative ...)