title: mnist dataset Lenet training
body: <p>I am new to caffe. To train Lenet with mnist dataset,I downloaded the data to the data/mnist in caffe. 
  When trying to convert to lmdb, using <code>./examples/mnist/create_mnist.sh</code> ,  I get error as :</p>
  
  <pre><code> Creating lmdb...
  F0225 16:39:23.937786 23330 convert_mnist_data.cpp:45] Check failed: image_file Unable to open file data/mnist/train-images-idx3-ubyte
  *** Check failure stack trace: ***
      @     0x7f5d0f0e8daa  (unknown)
      @     0x7f5d0f0e8ce4  (unknown)
      @     0x7f5d0f0e86e6  (unknown)
      @     0x7f5d0f0eb687  (unknown)
      @           0x4045df  convert_dataset()
      @           0x402943  main
      @     0x7f5d0de99ec5  (unknown)
      @           0x40298c  (unknown)
      @              (nil)  (unknown)
  Aborted (core dumped)
  F0225 16:39:24.025714 23334 convert_mnist_data.cpp:45] Check failed: image_file Unable to open file data/mnist/t10k-images-idx3-ubyte
  *** Check failure stack trace: ***
      @     0x7faa1af57daa  (unknown)
      @     0x7faa1af57ce4  (unknown)
      @     0x7faa1af576e6  (unknown)
      @     0x7faa1af5a687  (unknown)
      @           0x4045df  convert_dataset()
      @           0x402943  main
      @     0x7faa19d08ec5  (unknown)
      @           0x40298c  (unknown)
      @              (nil)  (unknown)
  Aborted (core dumped)
  Done.
  </code></pre>
  
  <p>Can somebody help me with this? What exactly could be the issue?</p>