title: Python numpy - Reproducibility of random numbers
body: <p>We have a very simple program (single-threaded) where we we do a bunch of random sample generation. For this we are using several calls of the <code>numpy</code> random functions (like <code>normal</code> or <code>random_sample</code>). Sometimes the result of one random call determines the number of times another random function is called.</p>
  
  <p>Now I want to set a seed in the beginning s.th. multiple runs of my program should yield the same result. For this I'm using an instance of the <code>numpy</code> class <code>RandomState</code>. While this is the case in the beginning, at some time the results become different and this is why I'm wondering.</p>
  
  <p>When I am doing everything correctly, having no concurrency and thereby a linear call of the functions AND no other random number generator involded, why does it not work?</p>