old_contents: #!/usr/bin/env python
  """
  Routes to LANL from 186 sites on the Internet.
  
  """
  __author__ = """Aric Hagberg (hagberg@lanl.gov)"""
  #    Copyright (C) 2004-2008
  #    Aric Hagberg <hagberg@lanl.gov>
  #    Dan Schult <dschult@colgate.edu>
  #    Pieter Swart <swart@lanl.gov>
  #    Distributed under the terms of the GNU Lesser General Public License
  #    http://www.gnu.org/copyleft/lesser.html
  
  
  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=nx.connected_component_subgraphs(G)[0]   
      G0.rtt={}
      for n in G0:
          G0.rtt[n]=time[n]
  
      return G0
  
  if __name__ == '__main__':
  
      import networkx as nx
      import math
  
      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"
  
      try: # drawing
          import matplotlib.pyplot as plt
          plt.figure(figsize=(8,8))
          # use graphviz to find radial layout
          pos=nx.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)
          plt.savefig("lanl_routes.png")
          print "Wrote lanl_routes.png"
      except:
          print "This example could not find either matplotlib or pygraphviz."
          pass
  
new_contents: #!/usr/bin/env python
  """
  Routes to LANL from 186 sites on the Internet.
  
  """
  __author__ = """Aric Hagberg (hagberg@lanl.gov)"""
  #    Copyright (C) 2004-2008
  #    Aric Hagberg <hagberg@lanl.gov>
  #    Dan Schult <dschult@colgate.edu>
  #    Pieter Swart <swart@lanl.gov>
  #    Distributed under the terms of the GNU Lesser General Public License
  #    http://www.gnu.org/copyleft/lesser.html
  
  
  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=nx.connected_component_subgraphs(G)[0]   
      G0.rtt={}
      for n in G0:
          G0.rtt[n]=time[n]
  
      return G0
  
  if __name__ == '__main__':
  
      import networkx as nx
      import math
  
      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"
  
      try: # drawing
          import matplotlib.pyplot as plt
          plt.figure(figsize=(8,8))
          # use graphviz to find radial layout
          pos=nx.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(xx for xx,yy in pos.values())
          plt.xlim(0,xmax)
          plt.ylim(0,ymax)
          plt.savefig("lanl_routes.png")
          print "Wrote lanl_routes.png"
      except:
          print "This example could not find either matplotlib or pygraphviz."
          pass
  
subject: adjust lanl_routes plot limits