Computes optimal \(\lambda\) for cross-validation output.
getmin_cpp(lambda, cvm, cvsd, which_lambda)
(vec) vector of \(\lambda\) parameters.
(vec) vector of cv error curve.
(vec) vector of standard errors for cv error curve.
which optimal \(\lambda\) to select; 0 - min of cv error curve, 1 - 1se min of cv error curve.