def dijkstra(gr, s):
dist = {}
paths = {}
for u in gr.getNodes():
dist[u.name] = sys.maxint
paths[u.name] = pathlist.pathlist()
#dist[s] = 0
nodeQ = gr.getNodes()
nodeQ.remove(gr.getNode(s))
print nodeQ
while nodeQ:
#nd = min(dist,key = lambda m: dist.get(m))
nd = getNodeWithMinDist(dist)
print nd
u = gr.getNode(nd)
print u
nodeQ.remove(u)
for v in u.getNeighbours():
alt = dist[u.name] + gr.operations.getEdgeBetween(u.name, v).weight
if alt < dist[v]:
dist[v] = alt
if not paths[u].getPaths():
p = path.path([v])
paths[v].addPath(p)
for p in paths[u].getPaths():
q = path.path(p.append(v))
paths[v] = paths[v].addPath(q)
elif alt == dist[v]:
p = path.path(paths[u.name].append(v))
paths[v] = paths[v].addPath(p)
return dist
def bfsBasedShortestPaths(gr, nd, allsp = False):
paths = {}
bfsqueue = []
for v in gr.getNodes():
paths[v.name] = pathlist.pathlist()
bfsqueue.append(nd)
paths[nd].addPath(path.path([nd]))
while bfsqueue:
u = bfsqueue.pop(0)
u = gr.getNode(u)
u.visited = True
for v in u.getNeighbours():
v = gr.getNode(v)
if not v.visited:
if not allsp:
v.visited = True
plen = sys.maxint
if paths[v.name].getPathList():
plen = paths[v.name].getPath().getPathLength()
for p in paths[u.name].getPathList():
if p.getPathLength() >= plen:
break
q = []
for n in p.getPathString().split():
q.append(n)
q.append(v.name)
paths[v.name].addPath(path.path(q))
if v.name not in bfsqueue:
bfsqueue.append(v.name)
paths[nd].reset()
del paths[nd]
gr.resetNodeVisitedFlags()
return paths
def bellmanFord(gr, s, sponly = True, allsp = False):
dist = {}
paths = {}
for u in gr.getNodeList():
dist[u] = sys.maxint/2
paths[u] = pathlist.pathlist()
dist[s] = 0
paths[s].addPath(path.path([s], weight = dist[s]))
nodes = gr.getNodes()
edges = gr.getEdges()
for i in range(gr.getNumNodes()):
for ed in edges:
u = ed.head
v = ed.tail
if sponly == False:
altPaths(v, paths[u], paths[v])
if not gr.directed:
u = ed.tail
v = ed.head
altPaths(v, paths[u], paths[v])
else:
alt = dist[u] + ed.weight
if alt < dist[v]:
relaxEdge(alt, v, dist, paths[u], paths[v])
if allsp:
if alt == dist[v]:
altPaths(v, paths[u], paths[v])
if not gr.directed:
u = ed.tail
v = ed.head
alt = dist[u] + ed.weight
if alt < dist[v]:
relaxEdge(alt, v, dist, paths[u], paths[v])
if allsp:
if alt == dist[v]:
altPaths(v, paths[u], paths[v])
paths[s].reset()
del paths[s]
if sponly:
for ed in edges:
u = ed.head
v = ed.tail
if not gr.directed:
if dist[v] > dist[u] + ed.weight and dist[u] > dist[v] + ed.weight:
print "Error: Graph contains a negative cycle!"
else:
if dist[v] > dist[u] + ed.weight:
print ed.name
print "Error: Graph contains a negative cycle!"
return paths
def __loadXml(self, in_buildXmlFilePath):
try:
document = xml.dom.minidom.parse(in_buildXmlFilePath)
except:
self.logError(
"load document failed " + in_buildXmlFilePath + " " +
str(sys.exc_value), True)
return
self.logMessage("")
self.__pathList = pathlist.pathlist(document, self)
self.__builderList = builderlist.builderlist(document, self)
self.__actionList = actionlist.actionlist(document, self)
def getAPSP(gr, allsp = False):
apsp = {}
nodes = gr.getNodeList()
for nd in nodes:
apsp[nd] = pathlist.pathlist()
paths = None
if not gr.weighted:
for nd in nodes:
paths = bfsbased.bfsBasedShortestPaths(gr, nd, allsp = False)
for v in paths.values():
for p in v.getPathList():
apsp[nd].addPath(p)
else:
for nd in nodes:
paths = bellman_ford.bellmanFord(gr, nd, allsp = False)
for v in paths.values():
for p in v.getPathList():
apsp[nd].addPath(p)
#apsp[nd] = paths
return apsp