This utility calculates the optimal TB3MS using the analytic solution.
jubilee.optimal_tb3ms(dtb, rs, penalty = c(1, 1, 1))data table, usually this is lm.dtb of the rs object,
with GDP log-return percent (logrp.N, logrp.K) calculated.
the list returned from jubilee.macro_fit.
numeric, the penalty vector for the models.
Default is c(1,1,1).
The data table containing the "optimal.tb3ms" column