#!/usr/bin/env python
"""
Routes to LANL from 186 sites on the Internet.
This uses Graphviz for layout so you need PyGraphviz or PyDotPlus.
"""
# Author: Aric Hagberg (hagberg@lanl.gov)
# Copyright (C) 2004-2016
# Aric Hagberg <hagberg@lanl.gov>
# Dan Schult <dschult@colgate.edu>
# Pieter Swart <swart@lanl.gov>
# All rights reserved.
# BSD license.
def lanl_graph():
""" Return the lanl internet view graph from lanl.edges
"""
import networkx as nx
try:
fh = open('lanl_routes.edgelist' , 'r')
except IOError:
print("lanl.edges not found")
raise
G = nx.Graph()
time = {}
time[0] = 0 # assign 0 to center node
for line in fh.readlines():
(head, tail, rtt) = line.split()
G.add_edge(int(head), int(tail))
time[int(head)] = float(rtt)
# get largest component and assign ping times to G0time dictionary
G0 = sorted(nx.connected_component_subgraphs(G), key = len, reverse=True)[0]
G0.rtt = {}
for n in G0:
G0.rtt[n] = time[n]
return G0
if __name__ == '__main__':
import networkx as nx
import math
try:
import pygraphviz
from networkx.drawing.nx_agraph import graphviz_layout
except ImportError:
try:
import pydotplus
from networkx.drawing.nx_pydot import graphviz_layout
except ImportError:
raise ImportError("This example needs Graphviz and either "
"PyGraphviz or PyDotPlus")
G=lanl_graph()
print("graph has %d nodes with %d edges"\
%(nx.number_of_nodes(G), nx.number_of_edges(G)))
print(nx.number_connected_components(G), "connected components")
import matplotlib.pyplot as plt
plt.figure(figsize=(8, 8))
# use graphviz to find radial layout
pos = graphviz_layout(G, prog="twopi", root=0)
# draw nodes, coloring by rtt ping time
nx.draw(G, pos,
node_color=[G.rtt[v] for v in G],
with_labels=False,
alpha=0.5,
node_size=15)
# adjust the plot limits
xmax = 1.02 * max(xx for xx,yy in pos.values())
ymax = 1.02 * max(yy for xx,yy in pos.values())
plt.xlim(0, xmax)
plt.ylim(0, ymax)
plt.savefig("lanl_routes.png")
