GitLab

* add neighbor sampler.

* fix sampler.

* handle non-existing nodes differently in MapParentIdToSubgraphId.

* fix sampling tests.

* parallelize sampling.

* add more tests.

* fix a bug in subgraph loader.

* get number of sampled nodes directly.

* load mxnet CSR to DGLGraph directly.

* create graph from mxnet csr array directly.

* use subgraph loader in SSE.

* fix a bug in sampling.

* output framework tensor.

* fix.

* remove unnecessary code.

* fix tests.

* add SSE README.

* move to contrib.

* address comments.

* add tests.

* pretty printer

* Conflicts:
	python/dgl/data/sbm.py

* refined line_graph implementation

* fix broken api calls

* small fix to trigger CI

* requested change

* add immutable graph index.

* update ImmutableGraphIndex.

* add benchmarks of subgraph generation.

* fix node_subgraphs.

* use scipy synthetic data in immutable graph.

* create immutable_graph.

* use spmv in gcn.

* fix immutable graph index.

* update graph index.

* create ImmutableSubgraphIndex.

* return subgraph node and edge mapping.

* fix benchmark.

* add mapping to subgraph nid.

* test in_edges and out_edges.

* update benchmark.

* Fix immutable subgraph.

* complete in_edges and out_edges.

* fix benchmarks.

* add test on node_subgraphs

* add sse.

* construct subgraphs in parallel.

* add in/out degree(s).

* make immutable graph index backend-specific.

* implement has_edge(s) and edge_id(s).

* Revert "use spmv in gcn."

This reverts commit 9cfed5f5fb3dd2ed9b98745348b1c0e9731ed7f7.

* implement node_subgraphs in GraphIndex.

* fix sse.

* address comments.

* address comments.

* Update mxnet docker.