Internal report, Dept. of Mathematics, Univ. of California at Berkeley, 1987

Abstract: We describe an algorithm to calculate the incomplete gamma function for complex arguments. The algorithm combines a power series with a continued fraction, in order to converge quickly for a wide range of argument values. In principle, arbitrary precision may be obtained. Such an algorithm is convenient since several well known functions are special cases of the incomplete gamma function. We include a double precision complex FORTRAN 77 implementation.