fixed subgraph edge_feat

pgl/graph.py

@@ -589,17 +589,12 @@ class Graph(object):
         if eid is None and edges is None:
             raise ValueError("Eid and edges can't be None at the same time.")
 
+        sub_edge_feat = {}
         if edges is None:
             edges = self._edges[eid]
         else:
             edges = np.array(edges, dtype="int64")
 
-        sub_edges = graph_kernel.map_edges(
-            np.arange(
-                len(edges), dtype="int64"), edges, reindex)
-
-        sub_edge_feat = {}
-        if edges is None:
         if with_edge_feat:
             for key, value in self._edge_feat.items():
                 if eid is None:
@@ -609,6 +604,10 @@ class Graph(object):
         else:
             sub_edge_feat = edge_feats
             
+        sub_edges = graph_kernel.map_edges(
+            np.arange(
+                len(edges), dtype="int64"), edges, reindex)
+
         sub_node_feat = {}
         if with_node_feat:
             for key, value in self._node_feat.items():