title: error with SAlib library for Sensitivity analysis in python
body: <p>I am trying to perform sensitivity analysis using Sobol`s method. I always get an error which i can not solve. the code and the result are below. the input variable ranges are identified in problem and the output of the model are saved in sens_out.txt</p>
  
  <pre><code>from SALib.sample import saltelli
  from SALib.analyze import sobol
  from SALib.test_functions import Ishigami
  import numpy as np
  import subprocess
  
  problem = {
      'num_vars': 30,
      'names': ['x1', 'x2', 'x3', 'x4', 'x5', 'x6', 'x7', 'x8', 'x9', 'x10',
                'x11', 'x12', 'x13', 'x14', 'x15', 'x16', 'x17', 'x18', 'x19',
                'x20', 'x21', 'x22', 'x23', 'x24', 'x25', 'x26', 'x27', 'x28',
                'x29', 'x30'],
      'bounds': [[2, 6],
                 [20, 30],
                 [600, 900],
                 [800, 1300],
                 [0.01, 0.05],
                 [0.1, 0.2],
                 [30, 35],
                 [0.0015, 0.003],
                 [0.001, 0.0015],
                 [0.50, 0.70],
                 [0.50, 0.70],
                 [0.50, 0.70],
                 [0.25, 0.50],
                 [0.0, 0.25],
                 [0.4, 0.5],
                 [0.5, 0.7],
                 [0.5, 0.7],
                 [0.5, 0.7],
                 [0.55, 0.7],
                 [0.6, 0.7],
                 [0.013, 0.017],
                 [0.027, 0.032],
                 [0.17, 0.21],
                 [0.007, 0.012],
                 [0.01, 0.016],
                 [0.02, 0.04],
                 [0.8, 1.2],
                 [2.0, 2.5],
                 [8, 12],
                 [90, 110]]
  }
  
  param_values = saltelli.sample(problem, 1000, calc_second_order=True)
  
  #np.savetxt("/home/omar/Desktop/param_values.txt", param_values)
  
  Y = np.loadtxt("/home/omar/Desktop/sens_out.txt", float)
  
  Si = sobol.analyze(problem, Y, print_to_console=True)
  </code></pre>
  
  <hr>
  
  <h2>Result = error message</h2>
  
  <pre><code>    Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/lib/python2.7/dist-packages/spyderlib/widgets/externalshell/sitecustomize.py", line 540, in runfile
      execfile(filename, namespace)
    File "/home/omar/Desktop/untitled0.py", line 58, in &lt;module&gt;
      Si = sobol.analyze(problem, Y, print_to_console=True)
    File "/home/omar/SALib/SALib/analyze/sobol.py", line 81, in analyze
      A,B,AB,BA = separate_output_values(Y, D, N, calc_second_order)
    File "/home/omar/SALib/SALib/analyze/sobol.py", line 164, in separate_output_values
      AB[:, j] = Y[(j + 1):Y.size:step]
  ValueError: could not broadcast input array from shape (1000,14) into shape (14000)
  </code></pre>