Creates a recency-frequency matrix for the holdout period.
dc.MakeRFmatrixHoldout(holdout.cbt)holdout period frequency customer-by-time matrix. This is a matrix consisting of a row per customer and a column per time period. It should contain the number of transactions each customer made per time period.
recency-frequency matrix for the holdout period, with three columns: frequency ("x.star"), recency ("t.x.star"), number of transaction opportunities in the holdout period ("n.star"), and the number of customers with each frequency-recency combination ("custs").