The (a+ib) derivative of f(x)

[dimension10]

Is there anyway to calculate successive derivatives of the form

\frac{{d}^{a+ib}}{d{x}^{a+ib}} [f(x)]

Thanks.

[pwsnafu]

If we are assuming f:\mathbb{R}\rightarrow \mathbb{R} this is precisely the RL-fractional (http://en.wikipedia.org/wiki/Riemann%E2%80%93Liouville_integral) derivative.

Find a book on fractional calculus and the most of the result transfer to complex orders directly.