_arraymethod : fallback when a method is called as MaskedArray.method

2 files changed, 21 insertions, 4 deletions

diff --git a/numpy/ma/core.py b/numpy/ma/core.py
index 29dc82815..14ba3ca8f 100644
--- a/numpy/ma/core.py
+++ b/numpy/ma/core.py
@@ -2124,11 +2124,16 @@ class _arraymethod(object):
     #
     def __call__(self, *args, **params):
         methodname = self.__name__
-        data = self.obj._data
-        mask = self.obj._mask
-        cls = type(self.obj)
+        instance = self.obj
+        # Fallback : if the instance has not been initialized, use the first arg
+        if instance is None:
+            args = list(args)
+            instance = args.pop(0)
+        data = instance._data
+        mask = instance._mask
+        cls = type(instance)
         result = getattr(data, methodname)(*args, **params).view(cls)
-        result._update_from(self.obj)
+        result._update_from(instance)
         if result.ndim:
             if not self._onmask:
                 result.__setmask__(mask)
diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index 1e127abff..3ac4fce9e 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -2272,6 +2272,18 @@ class TestMaskedArrayMethods(TestCase):
         assert_equal(test, a)
         assert_equal(test.data, a.data)
 
+
+    def test_arraymethod(self):
+        "Test a _arraymethod w/ n argument"
+        marray = masked_array([[1, 2, 3, 4, 5]], mask=[0, 0, 1, 0, 0])
+        control = masked_array([[1], [2], [3], [4], [5]],
+                               mask=[0, 0, 1, 0, 0])
+        assert_equal(marray.T, control)
+        assert_equal(marray.transpose(), control)
+        #
+        assert_equal(MaskedArray.cumsum(marray.T, 0), control.cumsum(0))
+
+
 #------------------------------------------------------------------------------