synced to 1.1 (expand() problem)

[ginac.git] / ginac / power.cpp

diff --git a/ginac/power.cpp b/ginac/power.cpp
index b38b733cb575667e0047fdad10383ccd3b53af0d..a45bf6afaf02aea954ebd6f2d6c0fe44476b3465 100644 (file)
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -839,6 +839,8 @@ ex power::expand_mul(const mul & m, const numeric & n) const
 
        epvector distrseq;
        distrseq.reserve(m.seq.size());
+       bool need_reexpand = false;
+
        epvector::const_iterator last = m.seq.end();
        epvector::const_iterator cit = m.seq.begin();
        while (cit!=last) {
@@ -847,11 +849,22 @@ ex power::expand_mul(const mul & m, const numeric & n) const
                } else {
                        // it is safe not to call mul::combine_pair_with_coeff_to_pair()
                        // since n is an integer
-                       distrseq.push_back(expair(cit->rest, ex_to<numeric>(cit->coeff).mul(n)));
+                       numeric new_coeff = ex_to<numeric>(cit->coeff).mul(n);
+                       if (is_exactly_a<add>(cit->rest) && new_coeff.is_pos_integer()) {
+                               // this happens when e.g. (a+b)^(1/2) gets squared and
+                               // the resulting product needs to be reexpanded
+                               need_reexpand = true;
+                       }
+                       distrseq.push_back(expair(cit->rest, new_coeff));
                }
                ++cit;
        }
-       return (new mul(distrseq, ex_to<numeric>(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated);
+
+       const mul & result = static_cast<const mul &>((new mul(distrseq, ex_to<numeric>(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated));
+       if (need_reexpand)
+               return ex(result).expand();
+       else
+               return result.setflag(status_flags::expanded);
 }
 
 } // namespace GiNaC