I need to compute the upper incomplete gamma function $$\Gamma(0,i\pi K)$$ where $i=\sqrt{-1}$ and K is real.
I have some basic idea about what this "special function" is, but am not used to using it. I am confused because MATLAB refuses to compute this for me - I get an error message says that inputs must be real.
The CAS wxMaxima computes it no problem with or without complex or inputs. How can I implement this in MATLAB?
In MATLAB the command I am using is 1 - gammainc(a,z)
In wxMaxima the command is gamma_incomplete(a,z)
or gamma_incomplete_regularized(a,z)
.
EDIT: What I mean to say here is that, in MATLAB, I want to get the same result that gamma_incomplete(a,z) gives in wxMaxima. For example, in wxMaxima the command gamma_incomplete(0,%i*%pi);
gives the output 0.28114072518757*%i-0.073667912046426
Now what do I have to do in MATLAB to get the same result?