Finally, the machine learning implementations for RF and GBT were accomplished in python 3, by using scikit-learn package  on a machine powered by intel® Core i7® at 3.2 GHz with 128 GB of memory (for cross validation). As long as the scikit-learn package includes multi-output regressor which is based on concatenation of individual regressors, the implementation of MOR was carried out with a package in R, called Multivariate Random Forest .