Add a comment, and fix macro name.
Add a comment, and fix macro name.

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