* Li2_do_sum_Xn: Optimize (avoid repeated multiplication).

diff --git a/ginac/inifcns_nstdsums.cpp b/ginac/inifcns_nstdsums.cpp
index 16f09691082cb52d0ddb50b50839566d72cf62d0..94d0fb0c1d3af9442977375b4f90120c972a0b1f 100644 (file)
--- a/ginac/inifcns_nstdsums.cpp
+++ b/ginac/inifcns_nstdsums.cpp
@@ -257,12 +257,13 @@ cln::cl_N Li2_do_sum_Xn(const cln::cl_N& x)
        std::vector<cln::cl_N>::const_iterator xend = Xn[0].end();
        cln::cl_N u = -cln::log(1-x);
        cln::cl_N factor = u * cln::cl_float(1, cln::float_format(Digits));
        std::vector<cln::cl_N>::const_iterator xend = Xn[0].end();
        cln::cl_N u = -cln::log(1-x);
        cln::cl_N factor = u * cln::cl_float(1, cln::float_format(Digits));

-       cln::cl_N res = u - u*u/4;
+       cln::cl_N uu = cln::square(u);
+       cln::cl_N res = u - uu/4;

        cln::cl_N resbuf;
        unsigned i = 1;
        do {
                resbuf = res;
        cln::cl_N resbuf;
        unsigned i = 1;
        do {
                resbuf = res;

-               factor = factor * u*u / (2*i * (2*i+1));
+               factor = factor * uu / (2*i * (2*i+1));

                res = res + (*it) * factor;
                i++;
                if (++it == xend) {
                res = res + (*it) * factor;
                i++;
                if (++it == xend) {