This function adds the linked information to a GP or DGP emulator if the information is not provided
when the emulator is constructed by gp() or dgp().
Usage
set_linked_idx(object, idx)
Value
An updated object with the information of idx incorporated.
Arguments
object
an instance of the S3 class gp or dgp.
idx
same as the argument linked_idx of gp() and dgp().