def kosaraju_strongly_connected_components(G,source=None):
"""Return nodes in strongly connected components of graph.
Parameters
----------
G : NetworkX Graph
An directed graph.
Returns
-------
comp : list of lists
A list of nodes for each component of G.
The list is ordered from largest connected component to smallest.
See Also
--------
connected_components
Notes
-----
Uses Kosaraju's algorithm.
"""
components=[]
post=nx.dfs_postorder(G,source=source,reverse_graph=True)
seen={}
while post:
r=post.pop()
if r in seen:
continue
c=nx.dfs_preorder(G,r)
new=[v for v in c if v not in seen]
seen.update([(u,True) for u in new])
components.append(new)
components.sort(key=len,reverse=True)
return components
def kosaraju_strongly_connected_components(G,source=None):
"""Return nodes in strongly connected components of graph.
Parameters
----------
G : NetworkX Graph
An directed graph.
Returns
-------
comp : list of lists
A list of nodes for each component of G.
The list is ordered from largest connected component to smallest.
See Also
--------
connected_components
Notes
-----
Uses Kosaraju's algorithm.
"""
components=[]
post=nx.dfs_postorder(G,source=source,reverse_graph=True)
seen={}
while post:
r=post.pop()
if r in seen:
continue
c=nx.dfs_preorder(G,r)
new=[v for v in c if v not in seen]
seen.update([(u,True) for u in new])
components.append(new)
components.sort(key=len,reverse=True)
return components
def restrict_to_target(self, target):
revgraph = self.graph.reverse()
nodes = nx.dfs_postorder(revgraph, target)
new_graph = self.graph.subgraph(nodes)
new_pipeline = Pipeline()
new_pipeline.graph = new_graph
new_pipeline.env = self.env
return new_pipeline
def restrict_to_target(self, target):
revgraph = self.graph.reverse()
nodes = nx.dfs_postorder(revgraph, target)
new_graph = self.graph.subgraph(nodes)
new_pipeline = Pipeline()
new_pipeline.graph = new_graph
new_pipeline.env = self.env
return new_pipeline
def test_postorder(self):
assert_equal(nx.dfs_postorder(self.G,source=0),[3, 4, 2, 1, 0])
def test_postorder(self):
assert_equal(nx.dfs_postorder(self.G, source=0), [3, 4, 2, 1, 0])
