BUG: Make ravel function return 1-D arrays for matrix argument.

This is a backward compatibility hack to avoid breaking scipy.sparse
after fixing ravel to respect subtypes. Subtypes are still respected
except in the case of matrices and subclasses of matrices.

2 files changed, 13 insertions, 8 deletions

diff --git a/numpy/core/fromnumeric.py b/numpy/core/fromnumeric.py
index da61fc187..2a527a4a4 100644
--- a/numpy/core/fromnumeric.py
+++ b/numpy/core/fromnumeric.py
@@ -1376,8 +1376,10 @@ def ravel(a, order='C'):
     Returns
     -------
     y : array_like
-        Array of the same type as `a`, and of shape ``(a.size,)``
-        or ``(1, a.size)`` for matrices.
+        If `a` is a matrix, y is a 1-D ndarray, otherwise y is an array of
+        the same subtype as `a`. The shape of the returned array is
+        ``(a.size,)``. Matrices are special cased for backward
+        compatibility.
 
     See Also
     --------
@@ -1435,7 +1437,10 @@ def ravel(a, order='C'):
     array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11])
 
     """
-    return asanyarray(a).ravel(order)
+    if isinstance(a, np.matrix):
+        return asarray(a).ravel(order)
+    else:
+        return asanyarray(a).ravel(order)
 
 
 def nonzero(a):
diff --git a/numpy/matrixlib/tests/test_defmatrix.py b/numpy/matrixlib/tests/test_defmatrix.py
index 93843c55c..f3a8e72ca 100644
--- a/numpy/matrixlib/tests/test_defmatrix.py
+++ b/numpy/matrixlib/tests/test_defmatrix.py
@@ -409,7 +409,7 @@ class TestShape(TestCase):
 
     def test_numpy_ravel(self):
         assert_equal(np.ravel(self.a).shape, (2,))
-        assert_equal(np.ravel(self.m).shape, (1, 2))
+        assert_equal(np.ravel(self.m).shape, (2,))
 
     def test_member_ravel(self):
         assert_equal(self.a.ravel().shape, (2,))
@@ -426,10 +426,10 @@ class TestShape(TestCase):
         assert_equal(np.ravel(x.T), [1, 4, 2, 5, 3, 6])
         assert_equal(np.ravel(x.T, order='A'), [1, 2, 3, 4, 5, 6])
         x = matrix([[1, 2, 3], [4, 5, 6]])
-        assert_equal(np.ravel(x), [[1, 2, 3, 4, 5, 6]])
-        assert_equal(np.ravel(x, order='F'), [[1, 4, 2, 5, 3, 6]])
-        assert_equal(np.ravel(x.T), [[1, 4, 2, 5, 3, 6]])
-        assert_equal(np.ravel(x.T, order='A'), [[1, 2, 3, 4, 5, 6]])
+        assert_equal(np.ravel(x), [1, 2, 3, 4, 5, 6])
+        assert_equal(np.ravel(x, order='F'), [1, 4, 2, 5, 3, 6])
+        assert_equal(np.ravel(x.T), [1, 4, 2, 5, 3, 6])
+        assert_equal(np.ravel(x.T, order='A'), [1, 2, 3, 4, 5, 6])
 
     def test_matrix_ravel_order(self):
         x = matrix([[1, 2, 3], [4, 5, 6]])