reference: https://github.com/martin-marek/score-centering @ fdca22b19793babdf08e33e5ba51537e82cbed2f; rl_score_centering.py sha256 2bbe1aab3583f79a7213afd1520d9f0d2893267f1ab236a22d4d86da53581956; sc_loss.py 0e5553db193feedb15bc86f6617e856eeb3f17ea94974da54332f67d1a6e1a95; common.py 3440f7829a075aa43f6f12d277e6c8309590f7065fdefd21d709cb055452bd55; parity_offline.py 6f56c29ebbe30f8d429ab5c88c23040c45928524c3c3926b513c3f52ec076e01; shared Spindle, no fork