title: scipy.interpolate.spline not working as intended
body: <p>I am a bit stumped on this one. I have used spline to smooth my data successfully, however it is just not working this time. Here is the snippet of the code that is not working. Any pointers would be highly appreciated. </p>
  
  <pre><code>In [46]: x
  
  Out[46]:
  array([  600.,   650.,   700.,   750.,   800.,   850.,   900.,   950.,
          1000.,  1050.,  1100.,  1150.,  1200.,  1250.])
  
  In [47]: y
  
  Out[47]:
  array([ 2.68530481,  3.715443  ,  4.11270841,  2.91720571,  1.49194971,
          0.24770035, -0.64713611, -1.40938122, -2.24634466, -3.04577225,
         -3.73914759, -4.35097303, -4.94702689, -5.56523414])
  
  In [48]: x2=numpy.linspace(x.min(),x.max(),20)
  
  In [49]: spline(x,y,x2)
  
  Out[49]:
  array([ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,
          0.,  0.,  0.,  0.,  0.,  0.,  0.])
  </code></pre>