The Faddeeva function (also called the Kramp function) is defined by $$w(z)=e^{-z^2} \left( 1 + \dfrac{2i}{\sqrt{\pi}} \displaystyle\int_0^x e^{t^2} dt \right)=e^{-z^2} \left[ 1 + \mathrm{erf}(iz)\right]=e^{-z^2} \mathrm{erfc}(-iz),$$ where $\mathrm{erf}$ denotes the error function and $\mathrm{erfc}$ denotes the complementary error function.