BUG: np.ma.mr_['r',...] does not return masked arrays

3 files changed, 17 insertions, 3 deletions

diff --git a/numpy/lib/index_tricks.py b/numpy/lib/index_tricks.py
index cece2b868..dc8eb1c4a 100644
--- a/numpy/lib/index_tricks.py
+++ b/numpy/lib/index_tricks.py
@@ -15,8 +15,6 @@ from .function_base import diff
 from numpy.core.multiarray import ravel_multi_index, unravel_index
 from numpy.lib.stride_tricks import as_strided
 
-makemat = matrixlib.matrix
-
 
 __all__ = [
     'ravel_multi_index', 'unravel_index', 'mgrid', 'ogrid', 'r_', 'c_',
@@ -238,6 +236,8 @@ class AxisConcatenator(object):
     """
     # allow ma.mr_ to override this
     concatenate = staticmethod(_nx.concatenate)
+    makemat = staticmethod(matrixlib.matrix)
+
     def __init__(self, axis=0, matrix=False, ndmin=1, trans1d=-1):
         self.axis = axis
         self.matrix = matrix
@@ -341,7 +341,7 @@ class AxisConcatenator(object):
 
         if matrix:
             oldndim = res.ndim
-            res = makemat(res)
+            res = self.makemat(res)
             if oldndim == 1 and col:
                 res = res.T
         return res
diff --git a/numpy/ma/extras.py b/numpy/ma/extras.py
index 10b9634a3..d55e0d1ea 100644
--- a/numpy/ma/extras.py
+++ b/numpy/ma/extras.py
@@ -1463,6 +1463,10 @@ class MAxisConcatenator(AxisConcatenator):
     """
     concatenate = staticmethod(concatenate)
 
+    @staticmethod
+    def makemat(arr):
+        return array(arr.data.view(np.matrix), mask=arr.mask)
+
     def __getitem__(self, key):
         # matrix builder syntax, like 'a, b; c, d'
         if isinstance(key, str):
diff --git a/numpy/ma/tests/test_extras.py b/numpy/ma/tests/test_extras.py
index 7de21ff59..4b7fe07b6 100644
--- a/numpy/ma/tests/test_extras.py
+++ b/numpy/ma/tests/test_extras.py
@@ -308,6 +308,16 @@ class TestConcatenator(TestCase):
     def test_matrix_builder(self):
         assert_raises(np.ma.MAError, lambda: mr_['1, 2; 3, 4'])
 
+    def test_matrix(self):
+        actual = mr_['r', 1, 2, 3]
+        expected = np.ma.array(np.r_['r', 1, 2, 3])
+        assert_array_equal(actual, expected)
+
+        # outer type is masked array, inner type is matrix
+        assert_equal(type(actual), type(expected))
+        assert_equal(type(actual.data), type(expected.data))
+
+
 class TestNotMasked(TestCase):
     # Tests notmasked_edges and notmasked_contiguous.