# Re: error function erf(z) with complex z

On Wed, Sep 07, 2005 at 12:03:28PM +0200, Thomas Weber wrote:
> Hello,
>
> > >>> from scipy.special import erf
> > >>> erf(2+3j)
> > (-20.829461428577808+8.6873182710560588j)
> Yes, thanks. Unfortunately, the library used for this is Fortran, so I'm
> still open for other suggestions.
>
>
It is not in Debian, but Matpack has an implementation for the Faddeeva
function:
w(z) = exp(-z^2)*erfc(-i*z),
where erfc is the complementary error function.
I extracted the "stand-alone" code, containing that function and adding the
plasma zeta function Z(z) = i*sqrt{pi} w(z), in which I was really interested.
I made C++ (Matpack is written in C++) and Octave versions, but I don't know
if it's ok to redistribute it, as it is basically the same code, with a few
lines commented to make faddeeva(z) independent of the rest of Matpack code.
>From the copyright notice:
"The software may be modified for your own purposes, but modified versions
may not be distributed without prior consent of the author."
Does extracting a single function from the code constitute a "modified
version"? What about translating an algorithm to another language?
Regards,
Victor

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