# I am searching for a C++ code implementing the complex polygamma function

I googled about some code on the complex polygamma function especially C++ code, but can't find anything. Does anyone know where to find such code?

The complex digamma function does exist but not the complex polygamma function.

Looking at what the python scipy library does for its special functions, the polygamma is found by returning the digamma if the zeroth derivative is requested, otherwise return $(-1)^{n+1}\Gamma(n+1)\zeta(n+1,z)$ where $\Gamma$ is the gamma function and $\zeta$ the two argument Riemann zeta function. Assuming that this identity holds for the complex numbers, it may explain why you can't find any explicit code.