Largest eigenvalue of \((X'X + \lambda I)^{-1}\), that is \(1 / (\lambda_{min}(X'X) + \lambda)\). Smaller is better. It uses the training set only. When X has more columns than rows, \(X'X\) is singular and the score is \(1/\lambda\) for every training set.
Details
See criteria for the list of criteria and the package website for one page per criterion.
References
Akdemir, D., & Isidro-Sanchez, J. (2019). Design of training populations for selective phenotyping in genomic prediction. Scientific Reports, 9, 1446. <doi:10.1038/s41598-018-38081-6>
Examples
data(geno)
eopt_score(geno[1:50, ])
#> [1] 404