The Best Rank Correlation Buys 0.24 Nanometres: Six Rhodopsin Wavelength Models on One FLIP2 Split
On the 184 held-out rows of the FLIP2 Rhomax by_wild_type split, with a frozen encoder and a fixed alpha-10 train-only ridge head and no tuning, the configuration with the best rank correlation (+0.42 Spearman, amino-acid composition) beats a constant training-mean prediction by 0.24 nm of mean absolute error, 95% paired cluster bootstrap over reconstructed background groups [−0.45, −0.05], which is below the 2 nm reporting threshold. The endpoint is peak absorption wavelength in nanometres and nothing else.
