如何使用networkx绘制社区

时间:2017-04-21 11:17:56

标签: python graph networkx

如何使用python networkx绘制带有社区的图形,如下图所示:

enter image description here

image url

1 个答案:

答案 0 :(得分:8)

networkx.draw_networkx_nodesnetworkx.draw_networkx_edges的文档说明了如何设置节点和边缘颜色。可以通过找到每个社区的节点位置然后绘制包含所有位置(然后是一些位置)的补丁(例如matplotlib.patches.Circle)来制作界定社区的补丁。

硬位是图形布局/设置节点位置。 AFAIK,在networkx中没有例程来实现所需的图形布局"开箱即用"。你想要做的是以下几点:

1)相对于彼此定位社区:创建一个新的加权图,其中每个节点对应一个社区,权重对应于社区之间的边数。使用您喜欢的图形布局算法(例如spring_layout)获得合适的布局。

2)定位每个社区内的节点:对于每个社区,创建一个新图。找到子图的布局。

3)在1)和3)中组合节点位置。例如。规模社区位置在1)中计算10倍;将这些值添加到该社区内所有节点的位置(如2中计算)。

我一直希望实现这一点。我可能会在今天晚些时候或周末这样做。

编辑:

瞧。现在你只需要在节点周围(后面)绘制你最喜欢的补丁。

Output of test()

import numpy as np
import matplotlib.pyplot as plt
import networkx as nx

def community_layout(g, partition):
    """
    Compute the layout for a modular graph.


    Arguments:
    ----------
    g -- networkx.Graph or networkx.DiGraph instance
        graph to plot

    partition -- dict mapping int node -> int community
        graph partitions


    Returns:
    --------
    pos -- dict mapping int node -> (float x, float y)
        node positions

    """

    pos_communities = _position_communities(g, partition, scale=3.)

    pos_nodes = _position_nodes(g, partition, scale=1.)

    # combine positions
    pos = dict()
    for node in g.nodes():
        pos[node] = pos_communities[node] + pos_nodes[node]

    return pos

def _position_communities(g, partition, **kwargs):

    # create a weighted graph, in which each node corresponds to a community,
    # and each edge weight to the number of edges between communities
    between_community_edges = _find_between_community_edges(g, partition)

    communities = set(partition.values())
    hypergraph = nx.DiGraph()
    hypergraph.add_nodes_from(communities)
    for (ci, cj), edges in between_community_edges.items():
        hypergraph.add_edge(ci, cj, weight=len(edges))

    # find layout for communities
    pos_communities = nx.spring_layout(hypergraph, **kwargs)

    # set node positions to position of community
    pos = dict()
    for node, community in partition.items():
        pos[node] = pos_communities[community]

    return pos

def _find_between_community_edges(g, partition):

    edges = dict()

    for (ni, nj) in g.edges():
        ci = partition[ni]
        cj = partition[nj]

        if ci != cj:
            try:
                edges[(ci, cj)] += [(ni, nj)]
            except KeyError:
                edges[(ci, cj)] = [(ni, nj)]

    return edges

def _position_nodes(g, partition, **kwargs):
    """
    Positions nodes within communities.
    """

    communities = dict()
    for node, community in partition.items():
        try:
            communities[community] += [node]
        except KeyError:
            communities[community] = [node]

    pos = dict()
    for ci, nodes in communities.items():
        subgraph = g.subgraph(nodes)
        pos_subgraph = nx.spring_layout(subgraph, **kwargs)
        pos.update(pos_subgraph)

    return pos

def test():
    # to install networkx 2.0 compatible version of python-louvain use:
    # pip install -U git+https://github.com/taynaud/python-louvain.git@networkx2
    from community import community_louvain

    g = nx.karate_club_graph()
    partition = community_louvain.best_partition(g)
    pos = community_layout(g, partition)

    nx.draw(g, pos, node_color=partition.values()); plt.show()
    return