title: What does the delayed() function do (when used with joblib in Python)
body: <p>I've read through the <a href="https://pythonhosted.org/joblib/parallel.html" rel="noreferrer">documentation</a>, but I don't understand what is meant by:
   <code>The delayed function is a simple trick to be able to create a tuple (function, args, kwargs) with a function-call syntax.</code></p>
  
  <p>I'm using it to iterate over the list I want to operate on (allImages) as follows:</p>
  
  <pre><code>def joblib_loop():
      Parallel(n_jobs=8)(delayed(getHog)(i) for i in allImages)
  </code></pre>
  
  <p>This returns my HOG features, like I want (and with the speed gain using all my 8 cores), but I'm just not sure what it is actually doing. </p>
  
  <p>My Python knowledge is alright at best, and it's very possible that I'm missing something basic. Any pointers in the right direction would be most appreciated</p>