svrep 0.6.4

• Fix issue #32: stack_replicate_designs() would only accept designs with types known to the 'survey' package. Fixed to allow other design types such as the random-groups jackknife.

• Added new helper function shuffle_replicates() to randomize the order of the columns of replicate weights. This is useful, for example, when replicates are created independently in each stratum and then combined.

• Added new helper function subsample_replicates() to retain a random subset of replicates and accordingly increase the scale factor used for variance estimation.

• Added new helper function add_inactive_replicates() which allows the user to add "inactive" replicates to a design object, so that the matrix of replicate weights has the desired number of columns.

• The function as_fays_gen_rep_design() now has a default value of mse = TRUE. Setting mse = FALSE will produce a warning message, since Fay's generalized replication method can sometimes produce large underestimates of variance when mse = FALSE.

• The function as_random_group_jackknife_design() now returns an object with class tbl_svy if the input was also an object with class tbl_svy.

• Generalized replication based on the Yates-Grundy estimator is now much faster due to code refactoring.