Helpfunction in update_g(), to calculate solve(FG x t(FG)) x FG
solveFG(TT, S, kg, factor_group, testing = FALSE)list: the number of elements in this list is equal to S (the number of groups). Each of the elements in this list has a number rows equal to the number of group specific factors, and TT columns.
length of time series
number of groups
vector with the estimated number of group specific factors for each group
estimated group specific factors
variable that determines if we are in 'testing phase'; defaults to FALSE (requires Matrix-package if set to TRUE)