Fix bug in inifcns_nstdsums.cpp...

[ginac.git] / ginac / inifcns_nstdsums.cpp

diff --git a/ginac/inifcns_nstdsums.cpp b/ginac/inifcns_nstdsums.cpp
index e2e48bc1eeeba031f67490d1ef6383110bf8e295..482afcd9fb61c963f6811fe4d158377ee1befa37 100644 (file)
--- a/ginac/inifcns_nstdsums.cpp
+++ b/ginac/inifcns_nstdsums.cpp
@@ -605,6 +605,27 @@ ex G_eval(const Gparameter& a, int scale, const exvector& gsyms)
        return pow(-1, x.nops()) * Li(m, x);
 }
 
+// convert back to standard G-function, keep information on small imaginary parts
+ex G_eval_to_G(const Gparameter& a, int scale, const exvector& gsyms)
+{
+       lst z;
+       lst s;
+       for (const auto & it : a) {
+               if (it != 0) {
+                        z.append(gsyms[std::abs(it)]);
+                       if ( it<0 ) {
+                         s.append(-1);
+                       } else {
+                         s.append(1);
+                       }
+               } else {
+                       z.append(0);
+                       s.append(1);
+               }
+       }
+       return G(z,s,gsyms[std::abs(scale)]);
+}
+
 
 // converts data for G: pending_integrals -> a
 Gparameter convert_pending_integrals_G(const Gparameter& pending_integrals)
@@ -844,8 +865,12 @@ ex G_transform(const Gparameter& pendint, const Gparameter& a, int scale,
                return result / trailing_zeros;
        }
 
-       // convergence case or flag_trailing_zeros_only
-       if (convergent || flag_trailing_zeros_only) {
+       // flag_trailing_zeros_only: in this case we don't have pending integrals
+       if (flag_trailing_zeros_only)
+               return G_eval_to_G(a, scale, gsyms);
+
+       // convergence case
+       if (convergent) {
                if (pendint.size() > 0) {
                        return G_eval(convert_pending_integrals_G(pendint),
                                      pendint.front(), gsyms) *