<p>Dropout is used in unsupervised learning. For example:</p>

<blockquote>
  <p>Shuangfei Zhai, Zhongfei Zhang: Dropout Training of Matrix Factorization and Autoencoder for Link Prediction in Sparse Graphs (<a href="http://arxiv.org/abs/1512.04483" rel="nofollow">arxiv</a>, 14 Dec 2015)</p>
</blockquote>
Why isn't DropOut used in Unsupervised Learning?
<p>All or nearly all of the papers using dropout are using it for supervised learning. It seems that it could just as easily be used to regularize deep autoencoders, RBMs and DBNs. So why isn't dropout used in unsupervised learning?</p>