Merge pull request #1 from smichr/sachin1

3532: Pow.is_real fix for base = -1
sympy · Nov 25, 2012 · c870c5c · c870c5c
2 parents 9bb61ed + b0edda5
commit c870c5c
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diff --git a/sympy/core/power.py b/sympy/core/power.py
@@ -217,6 +217,8 @@ def _eval_is_real(self):
                   self.base in [S.ImaginaryUnit, -S.ImaginaryUnit]):
                 return True
         if real_b and im_e:
+            if self.base is S.NegativeOne:
+                return True
             c = self.exp.coeff(S.ImaginaryUnit)
             if c:
                 ok = (c*C.log(self.base)/S.Pi).is_Integer

diff --git a/sympy/core/tests/test_assumptions.py b/sympy/core/tests/test_assumptions.py
@@ -613,3 +613,10 @@ def test_inconsistent():
     # cf. issues 2696 and 2446
     raises(InconsistentAssumptions, lambda: Symbol('x', real=True,
            commutative=False))
+
+
+def test_issue_3532():
+    assert ((-1)**(I)).is_real is True
+    assert ((-1)**(I*2)).is_real is True
+    assert ((-1)**(I/2)).is_real is True
+    assert ((-1)**(I*S.Pi)).is_real is True