Faddeeva function (FFT based)

Faddeeva function, aka plasma dispersion function

W = FADDEEVA(Z) is the Faddeeva function, aka the plasma dispersion function, for each element of Z. The Faddeeva function is defined as:

w(z) = exp(-z^2) erfc(-jz)

where erfc(x) is the complex complementary error function.

This code is a modified version of the code listed in:

J.A.C. Weideman, "Computation of the Complex Error Function," SIAM J. Numerical Analysis, pp. 1497-1518, No. 5, Vol. 31, Oct., 1994 Available Online: http://www.jstor.org/stable/2158232