calculate Pseudo-R2 for BRT
pseudo_r2_brt.RdUsed as part of eval_brt. From Camrin Brawn (WHOI): https://zenodo.org/records/7971532. Included with CVA2.0 package to ensure functionality.
pseudo_r2_brt.RdUsed as part of eval_brt. From Camrin Brawn (WHOI): https://zenodo.org/records/7971532. Included with CVA2.0 package to ensure functionality.