def makeGraphFromDict(name, dict):
"""
Updates this graph to be equal to a dictionary representation of a graph.
Essentially a secondary constructor using a dict
:param dict: Dictionary representation of a graph
:return: Graph object that is equivalent to dict
"""
graph = Graph(name)
communities = []
nodes = []
for nodeID, nodeValues in dict.items():
c = Community(nodeValues[1])
n = Node(nodeID)
if n not in nodes:
nodes.append(n)
for node in nodes:
if node == n:
n = node
for neighborID, arcWeight in nodeValues[0].items():
n2 = Node(neighborID)
if n2 not in nodes:
nodes.append(n2)
for node in nodes:
if node == n2:
n2 = node
e = Edge(n, n2, arcWeight)
if e not in graph.getEdges():
graph.addEdge(e)
n.addConnection(e)
n2.addConnection(e)
if c not in communities:
communities.append(c)
for comm in communities:
if c == comm:
c = comm
c.addMemberNode(n)
for node in nodes:
graph.addNode(node)
for c in communities:
graph.addCommunity(c)
return graph
def phaseTwo(graph):
"""
Consolidates communities toa single supernode, and adds edges to that node based on sum of weights between nodes from those communities.
Nodes will have self-edges with a weight equal to the number of edges between nodes in the community as described in the paper.
:param graph: A graph object
:return: A version of input graph corresponding to phase two of the blondel algorithm.
"""
newNodes = {}
newEdges = set()
newCommunities = []
# Create all supernodes, one per community
for community in graph.getCommunities():
id = community.getID()
node = Node(id)
id = community.getID()
c = Community(id)
c.addMemberNode(node)
newNodes[id] = node
newCommunities.append(c)
# Create all edges between supernodes
# Outer for loop will correspond to a supernode
for community in graph.getCommunities():
# This dictionary will store communityID as the key (these are same as supernode nodeID)
# and a numerical value representing the weight between two supernodes
newEdgeDict = {}
# This for loop corresponds to the edges between each supernode
for node in community.getMemberNodes():
neighborList = node.getNeighborCommunities()
# This loop calculates the weight of each new edge
for edge in node.getConnections():
otherNode = edge.getOtherNode(node)
nCommID = otherNode.getCommunity().getID()
if node == otherNode:
newEdgeDict[nCommID] = newEdgeDict.get(
nCommID, 0) + edge.getWeight()
elif nCommID == node.getCommunity().getID():
newEdgeDict[nCommID] = newEdgeDict.get(
nCommID, 0) + edge.getWeight() / 2
else:
newEdgeDict[nCommID] = newEdgeDict.get(
nCommID, 0) + edge.getWeight()
for key, weight in newEdgeDict.items():
n1 = newNodes[community.getID()]
n2 = newNodes[key]
e1 = Edge(n1, n2, weight)
e2 = Edge(n2, n1, weight)
if e1 not in newEdges and e2 not in newEdges:
n1.addConnection(e1)
n2.addConnection(e1)
newEdges.add(e1)
for nodeID, node in newNodes.items():
node.computeSumEdgeWeights()
for community in newCommunities:
community.computeInCommunityWeight()
p2graph = Graph(graph.getName(),
nodes=newNodes,
edges=newEdges,
communities=newCommunities)
return p2graph
