Merge pull request #4989 from juliantaylor/percentile-fix

juliantaylor · juliantaylor · commit 3f5ae6d9e783 · 2014-08-24T19:14:05.000+02:00
BUG: don't overwrite input percentile arrays
diff --git a/numpy/lib/function_base.py b/numpy/lib/function_base.py
@@ -3036,7 +3036,7 @@ def percentile(a, q, axis=None, out=None,
     array([ 3.5])
 
     """
-    q = asarray(q, dtype=np.float64)
+    q = array(q, dtype=np.float64, copy=True)
     r, k = _ureduce(a, func=_percentile, q=q, axis=axis, out=out,
                     overwrite_input=overwrite_input,
                     interpolation=interpolation)
diff --git a/numpy/lib/tests/test_function_base.py b/numpy/lib/tests/test_function_base.py
@@ -1865,6 +1865,14 @@ def test_percentile_no_overwrite(self):
         np.percentile(a, [50])
         assert_equal(a, np.array([2, 3, 4, 1]))
 
+    def test_no_p_overwrite(self):
+        p = np.linspace(0., 100., num=5)
+        np.percentile(np.arange(100.), p, interpolation="midpoint")
+        assert_array_equal(p, np.linspace(0., 100., num=5))
+        p = np.linspace(0., 100., num=5).tolist()
+        np.percentile(np.arange(100.), p, interpolation="midpoint")
+        assert_array_equal(p, np.linspace(0., 100., num=5).tolist())
+
     def test_percentile_overwrite(self):
         a = np.array([2, 3, 4, 1])
         b = np.percentile(a, [50], overwrite_input=True)
