.. _pylab_examples-system_monitor:

pylab_examples example code: system_monitor.py
==============================================



.. plot:: /home/tcaswell/src/p/matplotlib/doc/mpl_examples/pylab_examples/system_monitor.py

::

    import time
    import matplotlib.pyplot as plt
    import numpy as np
    
    
    def get_memory(t):
        "Simulate a function that returns system memory"
        return 100 * (0.5 + 0.5 * np.sin(0.5 * np.pi * t))
    
    
    def get_cpu(t):
        "Simulate a function that returns cpu usage"
        return 100 * (0.5 + 0.5 * np.sin(0.2 * np.pi * (t - 0.25)))
    
    
    def get_net(t):
        "Simulate a function that returns network bandwidth"
        return 100 * (0.5 + 0.5 * np.sin(0.7 * np.pi * (t - 0.1)))
    
    
    def get_stats(t):
        return get_memory(t), get_cpu(t), get_net(t)
    
    fig, ax = plt.subplots()
    ind = np.arange(1, 4)
    
    # show the figure, but do not block
    plt.show(block=False)
    
    
    pm, pc, pn = plt.bar(ind, get_stats(0))
    pm.set_facecolor('r')
    pc.set_facecolor('g')
    pn.set_facecolor('b')
    ax.set_xticks(ind)
    ax.set_xticklabels(['Memory', 'CPU', 'Bandwidth'])
    ax.set_ylim([0, 100])
    ax.set_ylabel('Percent usage')
    ax.set_title('System Monitor')
    
    start = time.time()
    for i in range(200):  # run for a little while
        m, c, n = get_stats(i / 10.0)
    
        # update the animated artists
        pm.set_height(m)
        pc.set_height(c)
        pn.set_height(n)
    
        # ask the canvas to re-draw itself the next time it
        # has a chance.
        # For most of the GUI backends this adds an event to the queue
        # of the GUI frameworks event loop.
        fig.canvas.draw_idle()
        try:
            # make sure that the GUI framework has a chance to run its event loop
            # and clear any GUI events.  This needs to be in a try/except block
            # because the default implementation of this method is to raise
            # NotImplementedError
            fig.canvas.flush_events()
        except NotImplementedError:
            pass
    
    stop = time.time()
    print("{fps:.1f} frames per second".format(fps=200 / (stop - start)))
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)