Fix bug introduced in previous commits.
Fix bug introduced in previous commits.

erubboli/mlpack,ajjl/mlpack,ranjan1990/mlpack,darcyliu/mlpack,erubboli/mlpack,lezorich/mlpack,lezorich/mlpack,ersanliqiao/mlpack,ajjl/mlpack,palashahuja/mlpack,ersanliqiao/mlpack,ranjan1990/mlpack,ranjan1990/mlpack,palashahuja/mlpack,stereomatchingkiss/mlpack,theranger/mlpack,erubboli/mlpack,darcyliu/mlpack,lezorich/mlpack,theranger/mlpack,stereomatchingkiss/mlpack,theranger/mlpack,stereomatchingkiss/mlpack,darcyliu/mlpack,ajjl/mlpack,BookChan/mlpack,BookChan/mlpack,BookChan/mlpack,ersanliqiao/mlpack,palashahuja/mlpack