Remove comment that is wrong. The remove0 op don't sort the indices.

theano/sparse/basic.py

@@ -2357,8 +2357,7 @@ def vstack(blocks, format=None, dtype=None):
 
 
 class Remove0(gof.Op):
-    """Remove explicit zeros from a sparse matrix, and
-    resort indices.
+    """Remove explicit zeros from a sparse matrix.
 
     :param x: Sparse matrix.
 

theano/sparse/tests/test_basic.py

@@ -1865,10 +1865,14 @@ class Remove0Tester(utt.InferShapeTester):
             ('csr', scipy.sparse.csr_matrix), ]
 
         for format, matrix_class in configs:
-            (x,), (mat,) = sparse_random_inputs(format, (3, 4),
+            for zero, unsor in [(True, True), (True, False),
+                              (False, True), (False, False)]:
+                (x,), (mat,) = sparse_random_inputs(format, (6, 8),
                                             out_dtype=config.floatX,
-                                        explicit_zero=True)
-            assert 0 in mat.data
+                                            explicit_zero=zero,
+                                            unsorted_indices=unsor)
+                assert 0 in mat.data or not zero
+                assert not mat.has_sorted_indices or not unsor
 
                 # the In thingy has to be there because theano has as rule not
                 # to optimize inputs
@@ -1894,6 +1898,12 @@ class Remove0Tester(utt.InferShapeTester):
                 mat.eliminate_zeros()
                 msg = 'Matrices sizes differ. Have zeros been removed ?'
                 assert result.size == target.size, msg
+                if unsor:
+                    assert not result.has_sorted_indices
+                    assert not target.has_sorted_indices
+                else:
+                    assert result.has_sorted_indices
+                    assert target.has_sorted_indices
 
     def test_infer_shape(self):
         mat = (numpy.arange(12) + 1).reshape((4, 3))