Internal function that does the backward step for the stepwise IM function.
backward_step(fit, data, formula, interactive_mode = FALSE,
genes_current = NULL, env_current = NULL, genes_dropped = NULL,
env_dropped = NULL, search = "genes", search_criterion = "AIC",
p_threshold = 0.2, exclude_worse_AIC = TRUE, max_steps = 100,
cv_iter = 5, cv_folds = 10, folds = NULL, Huber_p = 1.345,
classification = FALSE, start_genes = NULL, start_env = NULL,
eps = 0.01, maxiter = 100, family = gaussian, ylim = NULL,
seed = NULL, print = TRUE)
Current best fit.
If TRUE, the initial dataset is empty.
Same parameters as in the stepwise function.
Returns fit, start_genes, start_env and genes_current, genes_dropped if search="genes" or env_current and env_dropped if search="env".