DEP: Deprecate single-argument np.ma.m(in|ax)imum

This shorthand is just inconsistent with `np.maximum`, and just makes the
distinction between `np.ma.max` and `np.ma.maximum` even more confusing.

Also adds names to these objects, since 1) they're there in core, and 2) they
make the warning message more helpful.

4 files changed, 27 insertions, 13 deletions

diff --git a/numpy/ma/core.py b/numpy/ma/core.py
index 8861a3464..c3f80ea27 100644
--- a/numpy/ma/core.py
+++ b/numpy/ma/core.py
@@ -5673,10 +5673,7 @@ class MaskedArray(ndarray):
             "`mini` is deprecated; use the `min` method or "
             "`np.ma.minimum.reduce instead.",
             DeprecationWarning, stacklevel=2)
-        if axis is None:
-            return minimum(self)
-        else:
-            return minimum.reduce(self, axis)
+        return minimum.reduce(self, axis)
 
     def max(self, axis=None, out=None, fill_value=None, keepdims=np._NoValue):
         """
@@ -6371,9 +6368,18 @@ class _extrema_operation(object):
 
     """
 
+    @property
+    def __name__(self):
+        return self.ufunc.__name__
+
     def __call__(self, a, b=None):
         "Executes the call behavior."
         if b is None:
+            # 2016-04-13, 1.13.0
+            warnings.warn(
+                "Single-argument form of np.ma.{0} is deprecated. Use "
+                "np.ma.{0}.reduce instead.".format(self.__name__),
+                DeprecationWarning, stacklevel=2)
             return self.reduce(a)
         return where(self.compare(a, b), a, b)
 
diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index f807fc8ae..f20c9ba52 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -1049,8 +1049,8 @@ class TestMaskedArrayArithmetic(TestCase):
         xr = np.ravel(x)
         xmr = ravel(xm)
         # following are true because of careful selection of data
-        assert_equal(max(xr), maximum(xmr))
-        assert_equal(min(xr), minimum(xmr))
+        assert_equal(max(xr), maximum.reduce(xmr))
+        assert_equal(min(xr), minimum.reduce(xmr))
 
         assert_equal(minimum([1, 2, 3], [4, 0, 9]), [1, 0, 3])
         assert_equal(maximum([1, 2, 3], [4, 0, 9]), [4, 2, 9])
@@ -1060,12 +1060,12 @@ class TestMaskedArrayArithmetic(TestCase):
         y[0] = masked
         assert_equal(minimum(x, y), where(less(x, y), x, y))
         assert_equal(maximum(x, y), where(greater(x, y), x, y))
-        assert_(minimum(x) == 0)
-        assert_(maximum(x) == 4)
+        assert_(minimum.reduce(x) == 0)
+        assert_(maximum.reduce(x) == 4)
 
         x = arange(4).reshape(2, 2)
         x[-1, -1] = masked
-        assert_equal(maximum(x), 2)
+        assert_equal(maximum.reduce(x), 2)
 
     def test_minimummaximum_func(self):
         a = np.ones((2, 2))
diff --git a/numpy/ma/tests/test_deprecations.py b/numpy/ma/tests/test_deprecations.py
index d66980031..6b3c30e04 100644
--- a/numpy/ma/tests/test_deprecations.py
+++ b/numpy/ma/tests/test_deprecations.py
@@ -37,5 +37,13 @@ class TestArgsort(TestCase):
 		return self._test_base(np.ma.MaskedArray.argsort, np.ma.MaskedArray)
 
 
+class TestMinimumMaximum(TestCase):
+    def test_minimum(self):
+        assert_warns(DeprecationWarning, np.ma.minimum, np.ma.array([1, 2]))
+
+    def test_maximum(self):
+        assert_warns(DeprecationWarning, np.ma.maximum, np.ma.array([1, 2]))
+
+
 if __name__ == "__main__":
     run_module_suite()
diff --git a/numpy/ma/tests/test_old_ma.py b/numpy/ma/tests/test_old_ma.py
index 2ea53683d..51fa6ac36 100644
--- a/numpy/ma/tests/test_old_ma.py
+++ b/numpy/ma/tests/test_old_ma.py
@@ -182,8 +182,8 @@ class TestMa(TestCase):
         xmr = ravel(xm)
 
         # true because of careful selection of data
-        self.assertTrue(eq(max(xr), maximum(xmr)))
-        self.assertTrue(eq(min(xr), minimum(xmr)))
+        self.assertTrue(eq(max(xr), maximum.reduce(xmr)))
+        self.assertTrue(eq(min(xr), minimum.reduce(xmr)))
 
     def test_testAddSumProd(self):
         # Test add, sum, product.
@@ -444,8 +444,8 @@ class TestMa(TestCase):
         y[0] = masked
         assert_(eq(minimum(x, y), where(less(x, y), x, y)))
         assert_(eq(maximum(x, y), where(greater(x, y), x, y)))
-        assert_(minimum(x) == 0)
-        assert_(maximum(x) == 4)
+        assert_(minimum.reduce(x) == 0)
+        assert_(maximum.reduce(x) == 4)
 
     def test_testTakeTransposeInnerOuter(self):
         # Test of take, transpose, inner, outer products