S(0,p,x) now evaluates numerically

diff --git a/ginac/inifcns_nstdsums.cpp b/ginac/inifcns_nstdsums.cpp
index 3b7fc556892398c64180d6ffc78f4cdf4d242593..ec9586ed9367160fcd3b5a97fb5a3dda4db84ebf 100644 (file)
--- a/ginac/inifcns_nstdsums.cpp
+++ b/ginac/inifcns_nstdsums.cpp
@@ -939,9 +939,8 @@ numeric S_num(int n, int p, const numeric& x)
        else if (!x.imag().is_rational())
                prec = cln::float_format(cln::the<cln::cl_F>(cln::imagpart(value)));
 
-
        // [Kol] (5.3)
-       if (cln::realpart(value) < -0.5) {
+       if ((cln::realpart(value) < -0.5) || (n == 0)) {
 
                cln::cl_N result = cln::expt(cln::cl_I(-1),p) * cln::expt(cln::log(value),n)
                                   * cln::expt(cln::log(1-value),p) / cln::factorial(n) / cln::factorial(p);
@@ -1029,6 +1028,10 @@ static ex S_eval(const ex& n, const ex& p, const ex& x)
                        return S_num(ex_to<numeric>(n).to_int(), ex_to<numeric>(p).to_int(), ex_to<numeric>(x));
                }
        }
+       if (n.is_zero()) {
+               // [Kol] (5.3)
+               return pow(-log(1-x), p) / factorial(p);
+       }
        return S(n, p, x).hold();
 }