Algorithm 926, incomplete gamma functions with negative arguments. An algorithm for accurately computing the lower incomplete gamma function γ(a,t) in the case where a=n+1/2, n∈Z and t<0 is described. Series expansions and analytic continuation are employed to compute the function for certain critical values of n, and these results are used to initiate stable recurrence. The algorithm has been implemented in Fortran 2003, with precompuations carried out in Maple.

This software is also peer reviewed by journal TOMS.

Keywords for this software

Anything in here will be replaced on browsers that support the canvas element