Fixed some warnings
Fixed some warnings

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