Merge pull request #7511 from lesteve/fix-power-with-zero-exponent

jaimefrio · jaimefrio · commit b7a83d6f67be · 2016-04-05T17:24:18.000+02:00
numpy.power(0, 0) should return 1
diff --git a/numpy/core/src/umath/loops.c.src b/numpy/core/src/umath/loops.c.src
@@ -917,14 +917,14 @@ NPY_NO_EXPORT void
         @type@ in2 = *(@type@ *)ip2;
         @type@ out;
 
+        if (in2 == 0) {
+          *((@type@ *)op1) = 1;
+          continue;
+        }
         if (in2 < 0 || in1 == 0) {
             *((@type@ *)op1) = 0;
             continue;
         }
-        if (in2 == 0) {
-            *((@type@ *)op1) = 1;
-            continue;
-        }
 
         out = in2 & 1 ? in1 : 1;
         in2 >>= 1;
diff --git a/numpy/core/tests/test_umath.py b/numpy/core/tests/test_umath.py
@@ -430,6 +430,10 @@ def test_integer_power(self):
         b = a ** a
         assert_equal(b, [437893890380859375, 437893890380859375])
 
+    def test_integer_power_with_zero_exponent(self):
+        arr = np.arange(-10, 10)
+        assert_equal(np.power(arr, 0), np.ones_like(arr))
+
 
 class TestLog2(TestCase):
     def test_log2_values(self):
