CyRK's CySolver does not allow for complex-valued dependent variables.

[jrenaud90]

CyRK's CySolver only allows np.float64 y0 and dydt. This is due to limitations between fused types (used in cyrk_ode) and cython cdef classes.

A workaround is to convert your N-dimensional complex system of ODEs into a 2N-dimensional floating point system of ODEs. Pass this onto CySolver, and then convert the output back into complex values.

[jrenaud90]

I don't think we will support this; at least not any time soon. The work around of using 2x doubles instead of double complex is easy for the user compared with implementing a more generic type throughout CyRK.

If anything, it might be worth revisiting this if/when we ever want to add support for higher precision numbers.