#!/usr/bin/python

import time

try:
   import psutil
except ImportError:
   print "Cannot import psutil module - this is needed for this application.";
   print "Exiting..."
   sys.exit();
# end if


try:
   import matplotlib.pyplot as plt;   # Needed for plots
except:
   print "Cannot import matplotlib module - this is needed for this application.";
   print "Exiting..."
   sys.exit();
# end if


def column(matrix, i):
    return [row[i] for row in matrix]
# end def


# ===================
# Main Python section
# ===================
#
if __name__ == '__main__':

    # Main dictionary
    d = {};

    # define interval and add to dictionary
    interv = 0.5;
    d['interval'] = interv;

    # Number of cores:
    N = psutil.cpu_count();
    d['NCPUS'] = N;

    cpu_percent = [];
    epoch_list = [];
    for x in range(140):   # hard coded as an example
        cpu_percent_local = [];
        epoch_list.append(time.time());

        cpu_percent_local=psutil.cpu_percent(interval=interv,percpu=True);
        cpu_percent.append(cpu_percent_local);
    # end for

    # Normalize epoch to beginning
    epoch_list[:] = [x - epoch_list[0] for x in epoch_list];

    # Plots

    for i in range(N):
        A = column(cpu_percent, i);
        plt.plot(epoch_list, A);
    # end if
    plt.xlabel('Time (seconds)');
    plt.ylabel('CPU Percentage');
    plt.show();
# end if