RankGauss A data pre-processing technique for input normalization. Steps: take a column argsort it normalize the argsorted array to [-1, 1] range apply erfinv on it References: https://www.kaggle.com/c/porto-seguro-safe-driver-prediction/discussion/44629#250927 http://fastml.com/preparing-continuous-features-for-neural-networks-with-rankgauss/