basic_walkthrough Basic feature walkthrough caret_wrapper Use xgboost to train in caret library custom_objective Cutomize loss function, and evaluation metric boost_from_prediction Boosting from existing prediction predict_first_ntree Predicting using first n trees generalized_linear_model Generalized Linear Model cross_validation Cross validation create_sparse_matrix Create Sparse Matrix predict_leaf_indices Predicting the corresponding leaves early_stopping Early Stop in training poisson_regression Poisson Regression on count data