[Bugfix] MX utest traversal memory corruption (dmlc#312)

* WIP

* temp fix mx traversal memory crash bug

python/dgl/traversal.py

@@ -40,8 +40,8 @@ def bfs_nodes_generator(graph, source, reversed=False):
     [tensor([0]), tensor([1]), tensor([2, 3]), tensor([4, 5])]
     """
     ghandle = graph._graph._handle
-    source = utils.toindex(source).todgltensor()
-    ret = _CAPI_DGLBFSNodes(ghandle, source, reversed)
+    source = utils.toindex(source)
+    ret = _CAPI_DGLBFSNodes(ghandle, source.todgltensor(), reversed)
     all_nodes = utils.toindex(ret(0)).tousertensor()
     # TODO(minjie): how to support directly creating python list
     sections = utils.toindex(ret(1)).tonumpy().tolist()
@@ -80,8 +80,8 @@ def bfs_edges_generator(graph, source, reversed=False):
     [tensor([0]), tensor([1, 2]), tensor([4, 5])]
     """
     ghandle = graph._graph._handle
-    source = utils.toindex(source).todgltensor()
-    ret = _CAPI_DGLBFSEdges(ghandle, source, reversed)
+    source = utils.toindex(source)
+    ret = _CAPI_DGLBFSEdges(ghandle, source.todgltensor(), reversed)
     all_edges = utils.toindex(ret(0)).tousertensor()
     # TODO(minjie): how to support directly creating python list
     sections = utils.toindex(ret(1)).tonumpy().tolist()
@@ -161,8 +161,8 @@ def dfs_edges_generator(graph, source, reversed=False):
     [tensor([0]), tensor([1]), tensor([3]), tensor([5]), tensor([4])]
     """
     ghandle = graph._graph._handle
-    source = utils.toindex(source).todgltensor()
-    ret = _CAPI_DGLDFSEdges(ghandle, source, reversed)
+    source = utils.toindex(source)
+    ret = _CAPI_DGLDFSEdges(ghandle, source.todgltensor(), reversed)
     all_edges = utils.toindex(ret(0)).tousertensor()
     # TODO(minjie): how to support directly creating python list
     sections = utils.toindex(ret(1)).tonumpy().tolist()
@@ -232,10 +232,10 @@ def dfs_labeled_edges_generator(
     (tensor([0]), tensor([0]), tensor([0]), tensor([0]), tensor([0]), tensor([2]))
     """
     ghandle = graph._graph._handle
-    source = utils.toindex(source).todgltensor()
+    source = utils.toindex(source)
     ret = _CAPI_DGLDFSLabeledEdges(
             ghandle,
-            source,
+            source.todgltensor(),
             reversed,
             has_reverse_edge,
             has_nontree_edge,

tests/mxnet/test_propagate.py

@@ -23,7 +23,7 @@ def test_prop_nodes_bfs():
     assert np.allclose(g.ndata['x'].asnumpy(),
             np.array([[2., 2.], [4., 4.], [6., 6.], [8., 8.], [9., 9.]]))
 
-def _test_prop_edges_dfs():
+def test_prop_edges_dfs():
     g = dgl.DGLGraph(nx.path_graph(5))
     g.register_message_func(mfunc)
     g.register_reduce_func(rfunc)
@@ -69,6 +69,5 @@ def test_prop_nodes_topo():
 
 if __name__ == '__main__':
     test_prop_nodes_bfs()
-    #TODO(zhengda): the test leads to segfault in MXNet on Ubuntu 16.04.
-    #_test_prop_edges_dfs()
+    test_prop_edges_dfs()
     test_prop_nodes_topo()

tests/mxnet/test_traversal.py

@@ -84,7 +84,7 @@ def tensor_topo_traverse():
     assert all(toset(x) == toset(y) for x, y in zip(layers_dgl, layers_spmv))
 
 DFS_LABEL_NAMES = ['forward', 'reverse', 'nontree']
-def _test_dfs_labeled_edges(n=1000, example=False):
+def test_dfs_labeled_edges(n=1000, example=False):
     dgl_g = dgl.DGLGraph()
     dgl_g.add_nodes(6)
     dgl_g.add_edges([0, 1, 0, 3, 3], [1, 2, 2, 4, 5])
@@ -123,5 +123,4 @@ def combine_frontiers(sol):
 if __name__ == '__main__':
     test_bfs()
     test_topological_nodes()
-    #TODO(zhengda): the test leads to segfault in MXNet on Ubuntu 16.04.
-    #_test_dfs_labeled_edges()
+    test_dfs_labeled_edges()