title: Is np.set_printoptions() just for display purposes?
body: <p>I have the following code:</p>
  
  <pre><code>import numpy as np
  
  float_number_1 = -0.09115307778120041
  float_number_2 = -0.41032475233078003
  print(float_number_1)                              #-0.09115307778120041
  print(float_number_2)                              #-0.41032475233078003
  
  my_array= np.array([[float_number_1, float_number_2]], dtype=np.float64)
  for number in my_array:
      print(number)                                           #[-0.09115308 -0.41032475]
  </code></pre>
  
  <p>Now when I add the following:</p>
  
  <pre><code>np.set_printoptions(precision=50)
  </code></pre>
  
  <p>and print <strong>my_array</strong> again I get the full numbers:</p>
  
  <pre><code>[-0.09115307778120041 -0.41032475233078003]
  </code></pre>
  
  <p>Is set_printoptions  just for display purposes or does this affect the actual precision of the numbers held in the numpy array?
  I need to keep the precision for calculation purposes.</p>
  
  <p>Also, what is the maximum precision I can set for float64?</p>