title: Speedup MatchIt
body: <p>I am running a matching procedure in R, using the MatchIt package. I use propensity score match, that is: estimate treatment selection by logit, and pick the nearest match. </p>
  
  <p>The dataset is huge (4million rows), is there no way to speed it up?</p>
  
  <p>To make it clear what I have done:</p>
  
  <pre><code>require(MatchIt)
  m.out &lt;- matchit(treatment ~ age + agesq + male + income + ..., data = data, metod = "nearest")
  </code></pre>