def addEdge(self, line):
(left, right, weight) = line
# see http://stackoverflow.com/a/402704/2243495
if isinstance(left, int):
leftId = left
else:
leftId = self.getOrSetId(left)
if isinstance(right, int):
rightId = right
else:
rightId = self.getOrSetId(right)
if not self.weighted:
# we want to point from left to right with weight 1
weight = -1
if weight > 0:
lib.addEdgeByIds(self.graph, rightId, leftId, weight)
self.addWeight(left, weight)
self.addWeight(right, -weight)
elif weight < 0:
lib.addEdgeByIds(self.graph, leftId, rightId, -weight)
self.addWeight(right, -weight)
self.addWeight(left, weight)
else:
# lets not figure out how to handle this until it happens
raise Exception("zero weight")
return [left, right]
def test_graphCreation(self):
graph = lib.newGraph(4, -1, -1, -1, 1, 0)
ret = lib.addEdgeByIds(graph, 1, 2, 1)
self.assertEqual(ret, 0)
ret = lib.addEdgeByIds(graph, 2, 3, 1)
self.assertEqual(ret, 0)
ret = lib.addEdgeByIds(graph, 1, 3, 1)
self.assertEqual(ret, 0)
ret = lib.addEdgeByIds(graph, 0, 3, 1)
self.assertEqual(ret, 0)
# can't create more than 4 nodes
ret = lib.addEdgeByIds(graph, 3, 4, 1)
self.assertEqual(ret, -1)
self.assertEqual(lib.findNodeById(graph, 4), ffi.NULL)
# nodes have correct data
n = lib.findNodeById(graph, 1)
self.assertEqual(n.outDegree, 2)
self.assertLLValuesById(n.inNodes, [])
n = lib.findNodeById(graph, 2)
self.assertEqual(n.outDegree, 1)
self.assertLLValuesById(n.inNodes, [1])
n = lib.findNodeById(graph, 3)
self.assertEqual(n.outDegree, 0)
self.assertLLValuesById(n.inNodes, [2, 1, 0])
n = lib.findNodeById(graph, 0)
self.assertEqual(n.outDegree, 1)
self.assertLLValuesById(n.inNodes, [])
lib.cleanup(graph)
def test_computePageRank(self):
epsilon = 0.00001
nodeCount = 3
graph = lib.newGraph(nodeCount+10, 1, 0.5, epsilon, 2, 0)
lib.addEdgeByIds(graph, 1, 2, 1)
lib.addEdgeByIds(graph, 1, 3, 1)
lib.addEdgeByIds(graph, 2, 3, 1)
lib.addEdgeByIds(graph, 3, 1, 1)
lib.computeIteration(graph)
# initial pageRank
n = lib.findNodeById(graph, 1)
self.assertTrue(abs(n.pageRank_a - 1.0/graph.weightedSize) < epsilon)
n = lib.findNodeById(graph, 2)
self.assertTrue(abs(n.pageRank_a - 1.0/graph.weightedSize) < epsilon)
n = lib.findNodeById(graph, 3)
self.assertTrue(abs(n.pageRank_a - 1.0/graph.weightedSize) < epsilon)
while graph.converged == 0:
lib.computeIteration(graph)
# one more so both a and b have the converged page rank
lib.computeIteration(graph)
a = lib.findNodeById(graph, 1)
b = lib.findNodeById(graph, 2)
c = lib.findNodeById(graph, 3)
# the examples are not normalized so we must divide by nodeCount
# http://pr.efactory.de/e-pagerank-algorithm.shtml
self.assertTrue(abs(a.pageRank_a - 1.07692308 / nodeCount) < epsilon*10)
self.assertTrue(abs(a.pageRank_b - 1.07692308 / nodeCount) < epsilon*10)
self.assertTrue(abs(b.pageRank_a - 0.76923077 / nodeCount) < epsilon*10)
self.assertTrue(abs(b.pageRank_b - 0.76923077 / nodeCount) < epsilon*10)
self.assertTrue(abs(c.pageRank_a - 1.15384615 / nodeCount) < epsilon*10)
self.assertTrue(abs(c.pageRank_b - 1.15384615 / nodeCount) < epsilon*10)
lib.cleanup(graph)
