On Sat, 23 Mar 2019, Olasehinde Timmy wrote: Presumably v1, v2 and v12 should be scalars, not series, and the matrix V should be 2 x 2? For e1 and e2 both series, matrix U = {e1;e2} will not work. You can use {e1} and {e2} to convert the series to matrices, and the operator '~' or '|' to stick them together in whatever way makes sense. But what do you intend for the dimensions of U? Note that it (or its transpose) must be conformable for multiplication into inv(V), and the "ll" result must be either a scalar or a vector of length equal to the number of observations. Allin Cottrell