Cholesky-based FC sampling
Chol_samp_fun(Chol_vals, p, M, chol_diag, chol_offdiag, Chol_mat_blank)
Matrix of Cholesky factorizations (upper triangular values) for all prior sessions (nN*nM x nChol)
Pivot/reordering applied to FC matrices prior to Cholesky factorization
Number of samples to draw
Indices of diagonal upper triangular elements
Indices of off-diagonal upper triangular elements
A nLxnL matrix indexing the upper triangular elements