title: Training and Testing alphabets don't match issue, in making MaxEnt using Mallet
body: <p>I am new to Mallet and using it for making a MaxEnt model. What I want to achieve is I wanted to classify a text in some categories. (Using sample names for categories) I have my training data in a folder named as <code>fruits_training_data</code> which have 4 files:</p>
  
  <pre><code>apples.txt
  bananas.txt
  oranges.txt
  mangoes.txt
  </code></pre>
  
  <p>First I imported this data in mallet using this command.</p>
  
  <pre><code>bin\mallet import-dir --input fruits_training_data --output fruits_training.mallet
  </code></pre>
  
  <p>I had also test data for each category in separate folder and in separate files. It's hierarchy is also same. Folder name is <code>fruits_testing_data</code>. It has same file names as training folder. Same thing I did with test data.</p>
  
  <pre><code>bin\mallet import-dir --input fruits_testing_data --output fruits_testing.mallet
  </code></pre>
  
  <p>Then I am making MaxEnt model using this command.</p>
  
  <pre><code>bin\mallet train-classifier --training-file fruits_training.mallet --testing-file fruits_testing.mallet --trainer MaxEnt --report test:accuracy
  </code></pre>
  
  <p>This is giving me an error as:</p>
  
  <blockquote>
    <p>Training and testing alphabets don't match!
    at cc.mallet.classify.tui.Vectors2Classify.main(Vectors2Classify.java:27
    5)</p>
  </blockquote>
  
  <p>I searched this and did not find any help until now. Can someone help me to figure out at which step I am doing mistake? Will be thankful to you.</p>