Hi all, Lewis thank you for your help. Michael, I do agree with you. As you can read in my other last post "NLP modeling strategy",  I am trying to report some experiments that I've made. But on three reports I've just got one comment. When I have a doubt (I am not a NLP PRO, I mean I worked as an engineer and NLP is for fun) I ask a question (even if I do have my own point of view), hoping that somebody would be kind enough to share is point of view with me and potential reader. Sincerely JPG