def treeToPlan(tree):
""" given a tree, we compute a shortest open tour
@param tree: Tree, SpacialGraph,RewardGraph"""
odd_nodes = [n for n in tree.nodes() if len(tree.neighbors(n))%2==1
and n<>startnodelabel]
subgraph = tree.copy()
mwgraph = CompletelyConnected(tree.region)
for node in odd_nodes:
mwgraph.add_node(tree.location(node),id=node)
matching = mwgraph.getMinMatching()
marked = dict([(node,False) for node in odd_nodes])
#add the matching to the subtree
for n1,n2 in matching:
if not marked[n1]:
subtree.add_edge(n1,n2)
marked[n1] = marked[n2] = True
else:
print "marked"
#add an edge from the startnode to make the graph eulerian
lastnode = None
for n in subtree.nodes():
if n<>startnodelabel and len(subtree.neighbors(n))%2==1:
lastnode = n
break
if lastnode is not None:
lastedge = subtree.add_edge(startnodelabel,lastnode)
#compute euler tour
tour = subtree.eulerTour(start=startnodelabel)
if tour and lastnode is None:
pdb.set_trace()
#if the last node is first, reverse the tour
if len(tour)>2 and tour[0][1]==lastnode:
tour = tour[::-1]
return tour
def solve(self,graph,startnodelabel):
#compute MST of graph
tree = Tree(graph.toPygraph(),root=startnodelabel)
for node in tree.nodes():
if node<>startnodelabel:
tree.add_node_attribute(node,('reward',1.0))
#compute densest subtree of MST
rettree,retdist,retreward = computeMinSubsidy(startnodelabel,tree)
self.bid = retdist and retreward/retdist or 0
#compute min matching of subtree
subtree = mygraph()
subtree.add_node(startnodelabel)
for n in rettree:
if n<>startnodelabel:
subtree.add_node(n)
for n in rettree:
if n<>startnodelabel:
try:
subtree.add_edge(n,tree.parent(n))
except:
pdb.set_trace()
odd_nodes = [n for n in subtree.nodes() if len(subtree.neighbors(n))%2==1
and n<>startnodelabel]
mwgraph = CompletelyConnected(self.region)
for node in odd_nodes:
mwgraph.add_node(graph.location(node),id=node)
matching = mwgraph.getMinMatching()
marked = dict([(node,False) for node in odd_nodes])
#add the matching to the subtree
for n1,n2 in matching:
if not marked[n1]:
subtree.add_edge(n1,n2)
marked[n1] = marked[n2] = True
#add an edge from the startnode to make the graph eulerian
lastnode = None
for n in subtree.nodes():
if n<>startnodelabel and len(subtree.neighbors(n))%2==1:
lastnode = n
break
if lastnode is not None:
lastedge = subtree.add_edge(startnodelabel,lastnode)
#compute euler tour
tour = subtree.eulerTour(start=startnodelabel)
if tour and lastnode is None:
pdb.set_trace()
#if the last node is first, reverse the tour
if len(tour)>2 and tour[0][1]==lastnode:
tour = tour[::-1]
print rettree
#return the node sequence
#return [n2 for n1,n2,e in tour[:-1]]
return rettree