a function to apply cross-validation to select tuning parameter by minimizing SSE
cv.tuning.selection(data, lambda.seq, mu.seq, alpha_L = 0.25, nfold = 5)
a list of object, including
the grid of lamdbas and mus
final selected tuning parameter for sparse
final selected tuning parameter for low rank
a n by p dataset matrix
a numeric vector, indicates the sequence of tuning parameters of sparse components
a numeric vector, the sequence of tuning parameters of low rank components
a positive numeric value, indicating the constraint space of low rank components
a positive integer, the number of folds for cv