On Thu, 18 Jun 2009, Klein, Christoph wrote: Thanks! One comment: maybe I'm getting confused here, but I think the first modification should be old: if (!starting(p)) { return aux_any_node(p); --- new: if (!(starting(p) && r->t != VEC)) { return aux_any_node(p); while you had new: if (!(starting(p) || r->t == VEC)) { return aux_any_node(p); My thinking is that you want to _prevent_ this function from returning right away, if the "genr" is autoregressive and the 'r' node contains a series ('VEC') -- since you want it to be evaluated one observation at a time. Allin.