title: Scikit Learn GridSearchCV without cross validation (unsupervised learning)
body: <p>Is it possible to use GridSearchCV without cross validation? I am trying to optimize the number of clusters in KMeans clustering via grid search, and thus I don't need or want cross validation. </p>
  
  <p>The <a href="http://scikit-learn.org/stable/modules/generated/sklearn.model_selection.GridSearchCV.html" rel="noreferrer">documentation</a> is also confusing me because under the fit() method, it has an option for unsupervised learning (says to use None for unsupervised learning). But if you want to do unsupervised learning, you need to do it without cross validation and there appears to be no option to get rid of cross validation.</p>