Be more careful with conjugate(f(x)) -> f(conjugate(x)).

[ginac.git] / ginac / power.cpp

diff --git a/ginac/power.cpp b/ginac/power.cpp
index 4349ab7a59a47959d0d600607e7148dc13084a74..d24c969a2145d5a755d574c475a4ea57fd05d139 100644 (file)
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -667,12 +667,23 @@ ex power::eval_ncmul(const exvector & v) const
 
 ex power::conjugate() const
 {
-       ex newbasis = basis.conjugate();
-       ex newexponent = exponent.conjugate();
-       if (are_ex_trivially_equal(basis, newbasis) && are_ex_trivially_equal(exponent, newexponent)) {
-               return *this;
+       // conjugate(pow(x,y))==pow(conjugate(x),conjugate(y)) unless on the
+       // branch cut which runs along the negative real axis.
+       if (basis.info(info_flags::positive)) {
+               ex newexponent = exponent.conjugate();
+               if (are_ex_trivially_equal(exponent, newexponent)) {
+                       return *this;
+               }
+               return (new power(basis, newexponent))->setflag(status_flags::dynallocated);
+       }
+       if (exponent.info(info_flags::integer)) {
+               ex newbasis = basis.conjugate();
+               if (are_ex_trivially_equal(basis, newbasis)) {
+                       return *this;
+               }
+               return (new power(newbasis, exponent))->setflag(status_flags::dynallocated);
        }
-       return (new power(newbasis, newexponent))->setflag(status_flags::dynallocated);
+       return conjugate_function(*this).hold();
 }
 
 ex power::real_part() const