[Bug] DGLSubGraph.map_to_subgraph_nid error in v0.3

[mindlack]

Hello,

The method map_to_subgraph_nid from DGLSubGraph seems to malfunction.

The following example code:
import dgl
g=dgl.DGLGraph()
g.add_nodes(10)
h=g.subgraph([0,1,2,5,8])
h.map_to_subgraph_nid([0,8,2])

produces the following error chain:
File “.../python3.6/dist-packages/dgl/subgraph.py”, line 139, in map_to_subgraph_nid
return map_to_subgraph_nid(self._graph,utils.toindex(parent_vids)).tousertensor()
File “.../python3.6/dist-packages/dgl/graph_index.py”, line 1137, in map_to_subgraph_nid
return utils.toindex(_CAPI_DGLMapSubgraphNID(subgraph.induced_nodes.todgltensor(),
AttributeError: ‘GraphIndex’ object has no attribute ‘induced_nodes’

This bug does not occur in version 0.2 . The main difference I have found was that in v0.2 (in my code), type(h._graph) was
<class ‘dgl.graph_index.SubGraphIndex’>, instead of
<class ‘dgl.graph_index.GraphIndex’> as it is in v0.3 .

Am I using the library incorrectly? Is this behavior intended? If so, is there a replacement for the method?
Or is it a bug?

Thanks!

[jermainewang]

Thanks for reporting. Bug confirmed.

[lgalke]

Hey @jermainewang, is there a way I could contribute to fix this issue? This issue prevents me from upgrading beyond 0.2