edge2 = Edge(3, node2, node3) edge3 = Edge(2, node3, node4) edge4 = Edge(-6, node2, node4) edge5 = Edge(4, node1, node4) node1.adjacenciesList.append(edge1) node1.adjacenciesList.append(edge5) node2.adjacenciesList.append(edge4) node2.adjacenciesList.append(edge2) node3.adjacenciesList.append(edge3) vertexList = [node1, node2, node3, node4] edgeList = [edge1, edge2, edge3, edge4, edge5] algorithm = Algorithm() algorithm.calculateShortestPath(vertexList, edgeList, node1) algorithm.getShortestPathTo(node4) """ neg cycle proof edge1= Edge(5,node1,node2) edge2= Edge(3,node2,node3) edge3= Edge(2,node3,node4) edge4= Edge(-6,node4,node2) edge5= Edge(4,node1,node4) node1.adjacenciesList.append(edge1) node1.adjacenciesList.append(edge5) node2.adjacenciesList.append(edge2) node3.adjacenciesList.append(edge3) node4.adjacenciesList.append(edge4)
edge9 = Edge(5, vertexE, vertexH) edge10 = Edge(4, vertexE, vertexF) edge11 = Edge(20, vertexE, vertexG) edge12 = Edge(9, vertexD, vertexG) edge13 = Edge(3, vertexC, vertexD) edge14 = Edge(11, vertexC, vertexG) edge15 = Edge(1, vertexF, vertexC) edge16 = Edge(13, vertexF, vertexG) # define the relation between the edges and vertices vertexA.neighbourList.append(edge1) vertexA.neighbourList.append(edge2) vertexA.neighbourList.append(edge3) vertexB.neighbourList.append(edge4) vertexB.neighbourList.append(edge5) vertexB.neighbourList.append(edge6) vertexH.neighbourList.append(edge7) vertexH.neighbourList.append(edge8) vertexE.neighbourList.append(edge9) vertexE.neighbourList.append(edge10) vertexE.neighbourList.append(edge11) vertexD.neighbourList.append(edge12) vertexC.neighbourList.append(edge13) vertexC.neighbourList.append(edge14) vertexF.neighbourList.append(edge15) vertexF.neighbourList.append(edge16) # apply dijkstra's algorithm dijkstra = Algorithm() dijkstra.calculateShortestPath(vertexA) dijkstra.getShortestPathTo(vertexF)
vertexC.neighbourList.append(edge13)
vertexC.neighbourList.append(edge14)
vertexF.neighbourList.append(edge15)
vertexF.neighbourList.append(edge16)
vertexList = [
vertexA, vertexB, vertexC, vertexD, vertexE, vertexF, vertexG, vertexH
]
edgeList = [
edge1, edge2, edge3, edge4, edge5, edge6, edge7, edge8, edge9, edge10,
edge11, edge12, edge13, edge14, edge15, edge16
]
# apply Bellman-Ford algorithm
bellmanFord = Algorithm()
bellmanFord.calculateShortestPath(vertexList, edgeList, vertexA)
bellmanFord.getShortestPathTo(vertexG)
# to try a cycle example uncomment the code given below
# edge1 = Edge(1, vertexA, vertexB)
# edge2 = Edge(1, vertexB, vertexC)
# edge3 = Edge(1, vertexC, vertexD)
# edge4 = Edge(-15, vertexC, vertexB)
# edge5 = Edge(300, vertexA, vertexD)
#
# vertexA.neighbourList.append(edge1)
# vertexA.neighbourList.append(edge2)
# vertexB.neighbourList.append(edge3)
# vertexC.neighbourList.append(edge4)
# vertexC.neighbourList.append(edge5)
#
