graph_utils.py 文件源码

def refine_to_chain(g, from_attr, to_attr):
    '''can be used to refine basic blocks into blocks - the dual of contract_chains()
    assume g.node[n][attr] is a list
    returns a graph whose nodes are the refinement of the lists into paths
    the elements of the lists are held as to_attr
    the nodes become tuples (node_index, list_index)'''
    paths = []
    for n in g.nodes_iter():
        block = g.node[n][from_attr]
        size = len(block)
        path = nx.path_graph(size, create_using=nx.DiGraph())
        nx.relabel_nodes(path, mapping={x:(n, x) for x in path.nodes()}, copy=False)
        path.add_edges_from(((n, size - 1), (s, 0)) for s in g.successors_iter(n))
        paths.append(path)
    values = {(n, x): block
              for n in g.nodes_iter()
              for x, block in enumerate(g.node[n][from_attr])}
    res = nx.compose_all(paths)
    nx.set_node_attributes(res, to_attr, values)
    return res