import numpy as np
import matplotlib.pyplot as plt
import sys

if (not len(sys.argv) == 2):
  print("Please give the data file as the only argument for this program")
  sys.exit()

file_name = sys.argv[1]
data = np.loadtxt(file_name, delimiter = " ")

plt.figure()
plt.plot(data[:,0], data[:,1], '-bo')
if (np.shape(data)[1] == 3):
  plt.plot(data[:,0], data[:,1]/data[:,2]*100.0, '-r', linewidth=2)
  plt.legend(['Series','Analytical value'], loc = 4)
plt.grid()
plt.xlabel("i")
plt.ylabel("value")
plt.show()