title: Caffe layer registry error
body: <p>I'm new to Caffe and I have a problem running the Caffe mnist example. The error message is as follows:</p>
  
  <pre><code>I0607 00:24:12.260156  3593 net.cpp:67] Memory required for data: 0
  I0607 00:24:12.260167  3593 layer_factory.hpp:75] Creating layer mnist
  F0607 00:24:12.260180  3593 layer_factory.hpp:79] Check failed: registry.count(type) == 1 (0 vs. 1) Unknown layer type: Data (known types: )
  *** Check failure stack trace: ***
      @     0x7fe7f99a1ea4  (unknown)
      @     0x7fe7f99a1deb  (unknown)
      @     0x7fe7f99a17bf  (unknown)
      @     0x7fe7f99a4a35  (unknown)
      @           0x494fb5  caffe::LayerRegistry&lt;&gt;::CreateLayer()
      @           0x49725a  caffe::Net&lt;&gt;::Init()
      @           0x499c35  caffe::Net&lt;&gt;::Net()
      @           0x4a9d8b  caffe::Solver&lt;&gt;::InitTrainNet()
      @           0x4aa3b0  caffe::Solver&lt;&gt;::Init()
      @           0x4aa5a6  caffe::Solver&lt;&gt;::Solver()
      @           0x420af0  caffe::GetSolver&lt;&gt;()
      @           0x418b25  train()
      @           0x41465b  main
      @     0x7fe7f76c4a40  (unknown)
      @           0x415ac9  _start
      @              (nil)  (unknown)
  Aborted (core dumped)
  </code></pre>
  
  <p>I've searched for solutions and tried linking against dynamic library as suggested in <a href="https://stackoverflow.com/questions/30325108/caffe-layer-creation-failure">this post</a>. However it does not work. I can see the known layers is empty. What could be the cause? Please help me out. Thanks. I'm using Ubuntu 15.04.</p>