Python Graph.get_density方法代码示例

# 需要导入模块: from Graph import Graph [as 别名]
# 或者: from Graph.Graph import get_density [as 别名]

#.........这里部分代码省略.........
                    self.A[j].append(v)

    def complement_lists(self, l1, l2):
        ''' Elements of l1 not in l2 '''
        s2 = set(l2)
        l3 = [val for val in l1 if val not in s2]
        return l3

    def find_witnesses(self, i, vs, path):
        witnesses = {}
        for v in vs:
            w = self.find_witness(i, v, path)
            witnesses[v] = w

        return witnesses

    def find_witness(self, i, v, path):
        w = path[v]

        if w in self.A[i]:
            return w
        else:
            return self.find_witness(i, w, path)

    def find_dists(self, i_val):

        if i_val == self.k:
            delta = {}
            for v in self.v:
                delta[v] = np.inf

            return delta

        # Add source vertex
        self.g.add_vertex('s')
        for w in self.A[i_val]:
            self.g.add_edge('s', w, 0)

        # Elements not in A[i]
        subset = self.complement_lists(self.A[0], self.A[i_val])

        # Find witnesses
        delta, path = Dijkstra(self.g.get_graph(), 's')
        # witnesses = self.find_witnesses(i, subset, path)

        # Cleanup the graph
        self.g.remove_vertex('s')

        return delta

    def grow_shortest_tree(self, ai, delta):
        subset = self.complement_lists(self.A[ai], self.A[ai + 1])
        for w in subset:
            new_delta, path = Dijkstra(self.g.get_graph(), w, limit=delta[ai + 1])
            for p in path:
                source = p
                target = path[p]

                weight = self.g.get_edge_weight(source, target)
                self.spanner.add_edge(source, target, weight)

    def get_spanner(self):
        return self.spanner

    def find_stretch(self):
        already_iterated = set()
        stretch = 0.0
        for source in self.g.get_graph().iterkeys():
            for target in already_iterated:
                if target != source:
                    graph_dijk_distance, graph_dijk_preds = Dijkstra(self.g, source)
                    spanner_dijk_distance, spanner_dijk_preds = Dijkstra(self.spanner, source)

                    found_stretch = spanner_dijk_distance[target] / graph_dijk_distance[target]

                    if found_stretch > stretch:
                        stretch = found_stretch

            already_iterated.add(source)
        return stretch

    def get_csv_metrics(self, runtime):
        metrics = ",".join([self.spanner.get_cum_weight().__str__(),
                            self.spanner.get_density().__str__(),
                            self.spanner.get_highest_degree().__str__(),
                            runtime.__str__(),
                            self.find_stretch().__str__()])

        return metrics

    def nonrand_partition(self):
        V = self.g.get_vertices()

        self.A = {}
        self.A[0] = copy.deepcopy(V)
        self.A[1] = ['1', '2', '3', '4']
        self.A[2] = ['1', '2']
        self.A[3] = ['1']
        self.A[4] = ['1']
        self.A[5] = []

# 需要导入模块: from Graph import Graph [as 别名]
# 或者: from Graph.Graph import get_density [as 别名]
class Greedy(object):
    def __init__(self, org_graph, r):
        """

        :param Graph graph: is the graph of which we want to find a spanner
        :param int r: is the dialation factor, it is the maximum stretch
        :return:
        """

        self.org_graph = org_graph
        self.sorted_edges = self.to_sorted_edges()
        self.r_factor = r
        self.spanner = Graph()
        self.make_spanner()

    def make_spanner(self):

        for edge, weight in self.sorted_edges:
            v, u = edge
            if not self.spanner.has_vertex(v):
                self.spanner.add_vertex(v)
            if not self.spanner.has_vertex(u):
                self.spanner.add_vertex(u)

            dijk = Dijkstra(self.spanner, v)
            if not u in dijk[0] or (self.r_factor * weight) < dijk[0][u]:
                self.spanner.add_edge(v, u, weight)

    def to_sorted_edges(self,):
        """
        Fetches graph and parses it into edges
        :param {} graph_dict:
        :return:
        """
        edges = {}
        for source_entry, entries in self.org_graph.get_graph().iteritems():
            for target_entry, weight in entries.iteritems():
                # We don't want to add matching edge going in the other direction
                if not (edges.has_key((source_entry, target_entry)) or edges.has_key((target_entry, source_entry))):
                    edges[(source_entry, target_entry)] = weight
        sorted_edges = sorted(edges.items(), key=operator.itemgetter(1))
        return sorted_edges



    def get_csv_metrics(self, runtime):
        metrics = ",".join([self.spanner.get_cum_weight().__str__(),
                            self.spanner.get_density().__str__(),
                            self.spanner.get_highest_degree().__str__(),
                            runtime.__str__(),
                            self.find_stretch().__str__()])
        return metrics

    def get_spanner(self):
        return self.spanner

    def find_stretch(self):
        already_iterated = set()
        stretch = 0.0
        for source in self.org_graph.get_graph().iterkeys():
            for target in already_iterated:
                if target != source:
                    graph_dijk_distance, graph_dijk_preds = Dijkstra(self.org_graph, source)
                    spanner_dijk_distance, spanner_dijk_preds = Dijkstra(self.spanner, source)

                    found_stretch = spanner_dijk_distance[target] / graph_dijk_distance[target]

                    if found_stretch > stretch:
                        stretch = found_stretch

            already_iterated.add(source)
        return stretch