Graph Traversals

TODO: Expand this into a more detailed description of graph traversals

See pygrgl.get_bfs_order(), pygrgl.get_dfs_order(), and pygrgl.get_topo_order(). These methods take as input a list of seed nodes to start traversing from, and emit a node ordering for all nodes reachable from those seeds.

When the pygrgl.GRG.nodes_are_ordered property is True, the NodeIDs themselves provide a topological order of the graph. That is, iterating from 0...(grg.num_nodes-1) gives you a bottom-up topological order of the entire graph, and iterating from (grg.num_nodes-1)...0 gives you the top-down topological order. This property should be True for any GRG that has been read from disk (until it is modified).

In the Python API, often using pygrgl.matmul() is significantly faster than performing a traversal (even if you do not need to traverse the entire graph). See the next section for details on the dot product and when it is applicable.