Compilation error fix.
Compilation error fix.

ranjan1990/mlpack,BookChan/mlpack,ranjan1990/mlpack,darcyliu/mlpack,theranger/mlpack,trungda/mlpack,ajjl/mlpack,bmswgnp/mlpack,chenmoshushi/mlpack,datachand/mlpack,palashahuja/mlpack,ersanliqiao/mlpack,thirdwing/mlpack,trungda/mlpack,palashahuja/mlpack,stereomatchingkiss/mlpack,erubboli/mlpack,BookChan/mlpack,erubboli/mlpack,theranger/mlpack,palashahuja/mlpack,ranjan1990/mlpack,minhpqn/mlpack,ajjl/mlpack,theranger/mlpack,ersanliqiao/mlpack,thirdwing/mlpack,ersanliqiao/mlpack,chenmoshushi/mlpack,chenmoshushi/mlpack,datachand/mlpack,bmswgnp/mlpack,lezorich/mlpack,thirdwing/mlpack,darcyliu/mlpack,lezorich/mlpack,stereomatchingkiss/mlpack,darcyliu/mlpack,minhpqn/mlpack,minhpqn/mlpack,Azizou/mlpack,ajjl/mlpack,datachand/mlpack,BookChan/mlpack,Azizou/mlpack,Azizou/mlpack,erubboli/mlpack,lezorich/mlpack,stereomatchingkiss/mlpack,trungda/mlpack,bmswgnp/mlpack