title: Is it required to add mean of original train data to reduced dimension train and test data when using PCA?
body: <p>I have reduced test and train data dimension using PCA. Now I want to use svm for classification. Do  I need to add mean of original train data to pca reduced train and test data by command as follows:</p>
  
  <pre><code>X = bsxfun(@plus, pca_train_out, mean(train_data,1));
  Y = bsxfun(@plus, pca_test_out, mean(train_data,1));
  </code></pre>
  
  <p>Please guide.</p>