title: scikit-learn clustering: predict(X) vs. fit_predict(X)
body: <p>In scikit-learn, some clustering algorithms have both <code>predict(X)</code> and <code>fit_predict(X)</code> methods, like <em>KMeans</em> and <em>MeanShift</em>, while others only have the latter, like <em>SpectralClustering</em>. According to the doc:</p>
  
  <pre><code>fit_predict(X[, y]):    Performs clustering on X and returns cluster labels.
  predict(X): Predict the closest cluster each sample in X belongs to.
  </code></pre>
  
  <p>I don't really understand the difference between the two, they seem equivalent to me.</p>