GitLab

* bfs, dfs and topological traversal

* dfs and test cases

* Conflicts:
	python/dgl/graph.py
	src/graph/graph.cc
	src/graph/graph_op.cc

* documentation

* requested changes

* Conflicts:
	Jenkinsfile
	examples/pytorch/gcn/gcn.py
	examples/pytorch/gcn/gcn_spmv.py
	python/dgl/graph.py
	python/dgl/graph_index.py
	src/graph/graph.cc
	src/graph/graph_op.cc

* Conflicts:
	Jenkinsfile
	python/dgl/graph_index.py

* fix lint errors

* fix lint errors

* fix lint errors

* fix test cases

* requested changes

* traversal interface

* [Bug] fixed a typo that caused syntax error (#120)

* WIP

* bfs nodes generator works

* topological traversal

* WIP: dfs_edges

* dfs edges

* dfs labeled edges

* utest for traversal

* fix lint

* fix utest

* code clean

* changes as requested

* multigraph support on graph index

* more tests

* multigraph flag, bugfix on clear & copy

* networkx interfaces

* including graph index tests in Jenkins

* node subgraph test

* edge subgraphs

* removing duplicates in pred/succ

* more explicit test and doc

* query source and destination from edge id

* subgraphindex

* renaming has_edge to has_edge_between, apply_edges adding eid

* send_on and send_and_recv_on

* DGLGraph edge subgraph

* merged send_on and send_and_recv_on

* change request

* removing hashmap

* creating multigraph by flag; mingw support

* changes per request

* reverting networkx auto multigraph discovery

* notes on send/send_and_recv on multigraphs

* changing test reducer from sum to max

* added a fixme note in spmv scheduler