File:Barabasi Albert model.gif
Summary
| Description |
English: The evolution of a network by the Barabasi–Albert model. In every step, one new node appears, and in this case there is two new edges from the new node to the old ones.
Magyar: Egy hálózat fejlődése a Barabási–Albert modell szerint. Minden lépésben egy új csúcs jelenik meg, és ebben a változatban minden új csúcsból két él mutat a régi csúcsokhoz. |
| Date | |
| Source | Created by the NetworkX module of the Python |
| Author | Horváth Árpád |
The code is (using the python-networkx and python-matplotlib packages on Ubuntu GNU/Linux distribution):
#! /usr/bin/python
# coding: utf-8
import networkx
#import pylab
from pylab import pi, cos, sin, linspace, array
import matplotlib.pyplot as plt
import os
node_number = 20
initial_nodes = 2
animation = False
animation = True
G=networkx.barabasi_albert_graph(node_number, initial_nodes)
# pos=networkx.graphviz_layout(G, prog="dot")
type="shell4"
pos=networkx.shell_layout(G)
#pos=networkx.graphviz_layout(G,prog='twopi',args=)
print pos
dir=os.path.join("images", type)
if not os.path.isdir(dir):
os.mkdir(dir)
Ge = networkx.empty_graph(node_number)
#networkx.draw(GG,pos, node_color="w")
for i in range(initial_nodes,node_number):
nodes = range(i+1)
GG = G.subgraph(nodes)
plt.figure(figsize=(8,8))
networkx.draw(GG,pos, node_color="w", alpha=0.5, node_color="blue", node_size=20, with_labels=False, hold=False)
#networkx.draw(Ge,pos, node_color="w", alpha=0.5, node_color="blue", node_size=20, with_labels=False, hold=True)
#nx.draw(G,pos,node_size=20,alpha=0.5,node_color="blue", with_labels=False)
xmax=max(xx for xx,yy in pos.values())
xmin=min(xx for xx,yy in pos.values() + [(0,0)])
ymax=max(yy for xx,yy in pos.values())
ymin=min(yy for xx,yy in pos.values() + [(0,0)])
dx = xmax - xmin
ddx=0.1*dx
dy = ymax - ymin
ddy=0.1*dy
plt.xlim(xmin-ddx,xmax+ddx)
plt.ylim(ymin-ddy,ymax+ddy)
plt.savefig("%s/barabasi_%s%02d.png" % (dir, type, i))
if animation:
input = os.path.join(dir, "*.png")
output = os.path.join(dir, "barabasi_albert.gif")
os.system("convert -delay 100 -loop 0 %s %s" % (input, output))
(If someone knows how to eliminate the frame around the network, write to me, please.)
Licensing
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Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License. |
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