title: Scikit-learn dataset maker not accepting command-line arguments
body: <p>I'm working through a tutorial in Scikit-learn, and one section creates a dataset. This:</p>
  
  <pre><code>#Generate the example datapoints, red and blue.
  X, t = sklearn.datasets.make_circles(n_samples=100, shuffle=False, factor=0.3, noise=0.1)
  T = np.zeros((100,2))
  T[t==1,1] = 1
  T[t==0,0] = 1
  
  #Seperate the datapoints by color.
  x_red = X[t==0]
  x_blue = X[t==1]
  print ('shape of X: {}'.format(X.shape))
  print ('shape of T: {}'.format(T.shape))
  
  #Plotstuff
  plt.plot(x_red[:,0], x_red[:,1], 'ro', label='class red')
  plt.plot(x_blue[:,0], x_blue[:,1], 'bo', label='class blue')
  plt.grid()
  plt.legend(loc=1)
  plt.xlabel('$x_1$', fontsize=15)
  plt.ylabel('$x_2$', fontsize=15)
  plt.axis([-1.5, 1.5, -1.5, 1.5])
  plt.title('red vs. blue classes in the input space')
  plt.show()
  </code></pre>
  
  <p>Makes a completely normal <a href="http://i.stack.imgur.com/8Ygfd.png" rel="nofollow">chart</a>. </p>
  
  <p>However, when I change it to accept command line inputs:</p>
  
  <pre><code>    try:
          in1 = (int(float(sys.argv[1])))
          in2 = (int(float(sys.argv[2])))
          in3 = (int(float(sys.argv[3])))
          in4 = (int(float(sys.argv[4])))
      except IndexError:
          print(
          "The program is run as: program.py a b c d \n"
          "a = Random seed\n"
          "b = Number of samples\n"
          "c = Factor\n"
          "d = Noise\n"
          "Example: python JISIDF-[01].py 1 100 0.3 0.1")
          raise SystemExit
  
      np.random.seed(seed=in1)
      #Generate the example datapoints, red and blue.
      X, t = sklearn.datasets.make_circles(n_samples=in2, shuffle=False, factor=in3, noise=in4)
  </code></pre>
  
  <p>Even when the inputs are the same:</p>
  
  <pre><code>don@don-DELL:~/Code/Tutorials/Peterrolelant$ python3 PeterNet-17.py 1 100 0.3 0.1
  </code></pre>
  
  <p>I get an error:</p>
  
  <pre><code>    Traceback (most recent call last):
        File "PeterNet-17.py", line 27, in &lt;module&gt;
          X, t = sklearn.datasets.make_circles(n_samples=in2, shuffle=False, factor=in3, noise=in4)
        File "/usr/local/lib/python3.4/dist-packages/sklearn/datasets/samples_generator.py", line 625, in make_circles
          X += generator.normal(scale=noise, size=X.shape)
        File "mtrand.pyx", line 1902, in mtrand.RandomState.normal (numpy/random/mtrand/mtrand.c:17755)
      ValueError: scale &lt;= 0
  </code></pre>
  
  <p>This has been a problem before. How can I fix this?</p>