Python & NetworkX

1. Python & NetworkX 2013. 3 Youn-Hee Han LINK@KOREATECH http://link.koreatech.ac.kr

2. Why Python? • Python has been considered as a “godsend” to all developers. • It miraculously combines all the good things we always wanted • It is incredibly fast • It makes it easy to develop complex yet robust enterprise-level systems • It is designed to maintain clarity as development expands. • It enables “exploratory programming” LINK@KOREATECH

3. Installing Python 2.7 & NetworkX 1.7 LINK@KOREATECH

4. VirtualBox and Python 2.7.2 • Environment Recommendation  Ubuntu in VirtualBox • In this material… • Ubuntu 11.10 • Python 2.7.2 LINK@KOREATECH

5. iPython • iPython (http://ipython.org) • It is an enhanced Python shell and an architecture for interactive parallel computing. • It has everything to make your Python life much easier, from tab completion to inline code inspection and interactive debugging. • In addition, IPython has a special pylab mode for matplotlib. • Terminal • Qt Console • HTML Notebook • Just run: • easy_install ipython LINK@KOREATECH

6. NetworkX • NetworkX (http://networkx.lanl.gov/) • It is a Python language software package for the creation, manipulation, and study of the structure, dynamics, and functions of complex networks. • Just run: • easy_install networkx LINK@KOREATECH

7. numpy and matplotlib • numpy (http://networkx.lanl.gov/) • It is the fundamental Python package for scientific computing with Python. • It contains among other things: • a powerful N-dimensional array object • sophisticated (broadcasting) functions • tools for integrating C/C++ and Fortran code • useful linear algebra, Fourier transform, and random number capabilities • matplotlib (http://matplotlib.org/) • It is a python 2D plotting library which produces publication quality figures in a variety of hardcopy formats and interactive environments across platforms. • Just run: • easy_install numpy • easy_install matplotlib LINK@KOREATECH

8. numpy and matplotlib • Graphic Library  backend control • http://stackoverflow.com/questions/7534453/matplotlib-does-not-show-my-drawings-although-i-call-pyplot-show • Location of “matplotlibrc” file • /usr/local/lib/python2.7/dist-packages/matplotlib-1.2.0-py2.7-linux-i686.egg/matplotlib/mpl-data/matplotlibrc • Just run • easy_install PyGTK • [Note] In MAC OS, you use X11 • #backend : Agg • backend : GTK3Agg LINK@KOREATECH

9. Test Code • Simple Test Code • ipython simple.py simple.py • import networkx as net • import matplotlib.pyplot as plt • g=net.Graph() • g.add_edge('a','b') • net.draw(g) • plt.show() LINK@KOREATECH

10. Test Code basic_animation.py • Basic Animation • import numpy as np • import matplotlib.pyplot as plt • import matplotlib.animation as animation • def update_line(num, data, line): • line.set_data(data[...,:num]) • return line, • fig1 = plt.figure() • data = np.random.rand(2, 25) • l, = plt.plot([], [], 'r-') • plt.xlim(0, 1) • plt.ylim(0, 1) • plt.xlabel('x') • plt.title('test') • line_ani = animation.FuncAnimation(fig1, update_line, 25, fargs=(data, l), • interval=50, blit=True) • #line_ani.save('lines.mp4') • fig2 = plt.figure() • x = np.arange(-9, 10) • y = np.arange(-9, 10).reshape(-1, 1) • base = np.hypot(x, y) • ims = [] • for add in np.arange(15): • ims.append((plt.pcolor(x, y, base + add, norm=plt.Normalize(0, 30)),)) • im_ani = animation.ArtistAnimation(fig2, ims, interval=50, repeat_delay=3000, blit=True) • #im_ani.save('im.mp4', metadata={'artist':'Guido'}) • plt.show() LINK@KOREATECH