Beispiel #1
0
def johnson_algorithm(graph: DirectedGraph) -> list:
    if graph.repr_type != RepresentationType.ADJACENCY_MATRIX:
        graph.to_adjacency_matrix()

    g = graph.repr

    # add vertex to graph and add edges of value 0 from this vertex to the rest
    g.append([0])
    for i in range(len(g) - 2):
        g[len(g) - 1].append(0)

    for i in range(len(g)):
        g[i].append(None)

    graph.to_adjacency_list()
    edges = bellman_ford(graph, len(g))
    edges.pop(len(g))
    graph.to_adjacency_matrix()

    new_g = [[0 for x in range(len(g) - 1)] for y in range(len(g) - 1)]

    for i in range(len(new_g)):
        for j in range(len(new_g[i])):
            if g[i][j] is not None:
                new_g[i][j] = (g[i][j] + edges[i + 1] - edges[j + 1])

    graph.repr.pop()
    for i in range(len(graph.repr)):
        graph.repr[i].pop()

    graph_for_dijkstra = Graph()
    data = get_graph_with_probability(len(graph.repr), 0.5)
    graph_for_dijkstra.load_data(
        data=data,
        representation_type=RepresentationType.ADJACENCY_MATRIX_WITH_WEIGHTS)

    for i in range(len(graph.repr)):
        for j in range(len(graph.repr[i])):
            graph_for_dijkstra.repr[i][j] = new_g[i][j]

    dist_matrix = []
    for s in range(len(graph_for_dijkstra.repr)):
        print(f"For node [{s+1}]:")
        from_point = find_shortest_path(
            G=graph_for_dijkstra.get_weighted_adjacency_list(),
            start=s + 1,
            verbose=True)
        dist_matrix.append([])
        for node in from_point:
            dist_matrix[s].append(from_point[node])
        print()
    return dist_matrix
import os, sys

currentdir = os.path.dirname(os.path.realpath(__file__))
parentdir = os.path.dirname(currentdir)
sys.path.append(parentdir)

from utils.Graph import Graph, RepresentationType
from utils.graph_generators import gen_random_conn_graph_weighted
from utils.graph_plotter import GraphPlotter
from algorithms.dijkstra import find_shortest_path

if __name__ == "__main__":
    random_conn_graph = gen_random_conn_graph_weighted(10)

    G = Graph()
    G.load_data(
        data=random_conn_graph,
        representation_type=RepresentationType.ADJACENCY_MATRIX_WITH_WEIGHTS)
    print(G)
    GraphPlotter.plot_graph(G, draw_wages=True)

    s = 1
    print(50 * '-')
    print("START: s = {0}".format(s))

    print(
        find_shortest_path(G=G.get_weighted_adjacency_list(),
                           start=s,
                           verbose=True))

    # print(G.get_weighted_adjacency_list())